JP3327915B2 - Transmission device, reception device, transmission device, transmission method, reception method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transmission apparatus for transmitting a digital signal by modulating a carrier wave.

[0002]

2. Description of the Related Art In recent years, digital transmission devices have been increasingly used in various fields. In particular, the development of digital video transmission technology is remarkable.

[0003] Among them, a digital TV transmission system has recently attracted attention. At present, digital TV transmission devices are only partially used for relaying between broadcasting stations. However, development to terrestrial broadcasting and satellite broadcasting is scheduled in the near future, and studies are being conducted in various countries.

[0004] In order to respond to the demands of increasingly sophisticated consumers, H
It is necessary to improve the quality and quantity of contents of broadcasting services such as DTV broadcasting, PCM music broadcasting, information providing broadcasting and FAX broadcasting in the future. In this case, it is necessary to increase the amount of information in a limited frequency band of TV broadcasting. The amount of information that can be transmitted in this band increases according to the technological limitations of the era. For this reason, it is ideally desirable to change the receiving system according to the times and expand the information transmission amount.

[0005] However, from the viewpoint of broadcasting, publicity is important, and it is important to secure vested rights of all viewers for a long period of time. When starting a new broadcasting service, it is a necessary condition that the existing receiver or receiver can enjoy the service. It can be said that the compatibility of the receiver or the receiver and the compatibility of the broadcasting between the past and present, and the present and future new and old broadcasting services are the most important.

[0006] New transmission standards that will appear in the future, such as the digital TV broadcasting standard, require expandability of the amount of information to meet future social requirements and technological advances, and compatibility and compatibility with existing receiving equipment. Have been.

[0007] Here, transmission systems of TV broadcasting that have been proposed so far will be described from the viewpoint of expandability and compatibility.

First, as a satellite broadcasting system of digital TV, N
A method has been proposed in which a signal obtained by compressing a TSC-TV signal to about 6 Mbps is multiplexed by a TDM method using 4-level PSK modulation and a single transponder broadcasts a TV program of 4 to 20 channels NTSC or one channel of HDTV. As a terrestrial broadcasting method of HDTV, a method of compressing a 1-channel HDTV video signal into data of about 15 Mbps and performing terrestrial broadcasting using a 16 or 32 QAM modulation method is being studied.

First, in the satellite broadcasting system, the currently proposed broadcasting system uses the NTSC frequency band of several channels for one-channel HDTV program broadcasting in order to simply broadcast by the conventional transmission system. For this reason, HDT
There is a problem that the NTSC program of several channels cannot be received and broadcast in the broadcast time zone of the V program. NTSC and H
It can be said that there was no compatibility or compatibility between the receiver and the receiver with the DTV broadcast. It can also be said that the scalability of the amount of information transmission required with future technological advances was not considered at all.

Next, the conventional HDT which is currently under study
V terrestrial broadcasting system uses HDTV signals of 16QAM or 32Q
It merely broadcasts in a conventional modulation scheme such as AM. In the case of the existing analog broadcasting, there is always an area having a bad reception state such as a building shadow, a lowland, or interference from an adjacent TV station even in the broadcasting service area.
In such an area, although the image quality deteriorates in the case of the existing analog broadcasting, the video can be reproduced and the TV program can be viewed. However, the conventional digital TV broadcasting system has a serious problem that no video can be reproduced at all in such an area and that no TV program can be viewed. This involves an essential problem of digital TV broadcasting, and was a problem that could be fatal to the spread of digital TV broadcasting. This is because the signal points of the conventional modulation method such as QAM or the like are arranged at equal positions or at equal intervals. Conventionally, there has been no method of changing or modulating the arrangement of signal points.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and in particular, NTSC in satellite broadcasting.
It is an object of the present invention to provide a transmission apparatus which greatly reduces the compatibility between broadcasting and HDTV broadcasting, and greatly reduces unreceivable areas in a service area for terrestrial broadcasting.

[0012]

To achieve the above object, a transmission apparatus according to the present invention comprises a signal input section, a carrier wave modulated by an input signal from the input section, and an m-value signal on a signal vector diagram. A transmitting device for transmitting data, comprising a modulating unit for generating a point and a transmitting unit for transmitting a modulated signal, an input unit for the transmitting signal, and a signal point of a P value on a vector diagram that can be expressed in a polar coordinate system (r, θ) Modified PSK or Modified APS
It has two configurations: a demodulator that demodulates K modulated waves and a receiving device that has an output unit.

[0013]

With this configuration, a first data sequence and a second data sequence having n-valued data are input as input signals, and the modulator of the transmitting apparatus modifies the m-valued QAM having m-valued signal points on the vector diagram by the modulator of the transmitting device. Create a modulated wave of the system. The m signal points are divided into n sets of signal points, and the signal points are assigned to n data in the first data string, and m / n
Each data of the second data string is allocated to the signal point or the sub-signal point group, trellis-encoded, modulated, and transmitted by the transmitting device. In some cases, the third data can also be transmitted.

Next, in a receiving apparatus having a demodulator having a p-value of p> m, the above-mentioned transmission signal is received, and p signal points are first set to n points on the signal space diagram. , And demodulate and reproduce the signal of the first data string. Next, p / n signal points in the corresponding signal point group are associated with the second data sequence of p / n values and demodulated to demodulate and reproduce the first data and the second data. At this time, the first data string and / or the second data string are trellis-encoded.
In a receiver with p = n, n groups of signal points are reproduced, and only the first data string is demodulated and reproduced with each having an n value.

When the same signal is received from the transmitting device by the above operation, the first data sequence and the second data sequence can be demodulated by the large antenna and the receiver having multi-level demodulation capability.
At the same time, a small antenna and a receiver having a small demodulation capability can receive the first data string. Thus, a compatible transmission system can be constructed. In this case, the first data string is a low-frequency TV such as a low-frequency component of NTSC or HDTV.
In the signal, a second data string is added to a high frequency T such as a high frequency component of an HDTV.
By allocating to the V signal, a receiver having a small demodulation capability with respect to the same radio wave can receive an NTSC signal, and a receiver having a multi-level demodulation capability can receive an HDTV signal. This enables digital broadcasting compatible with NTSC and HDTV.

[0016]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In the embodiment of the present invention, a digital signal such as a digital HDTV signal is transmitted, and a digital signal such as an HDTV signal is recorded on a recording medium such as a magnetic tape or a transmission device comprising a combination of a transmitter and a receiver for receiving. Then, both of the recording / reproducing apparatuses for reproducing will be described.

However, the operation principle of the digital modulation / demodulation unit, the encoder for error correction, the encoder for decoding an image such as an HDTV signal, and the decoder of the present invention is common to the transmission apparatus and the recording / reproducing apparatus. The same technology. Accordingly, in each embodiment, the present invention will be described with reference to a block diagram of one of the transmission device and the recording / reproducing device for efficient description. In addition, the configuration of each embodiment of the present invention is similar to the configuration of Constel such as QAM, ASK, and PSK.
Any multi-level digital modulation scheme that arranges signal points on the Lation can be applied, but a description will be given using one modulation scheme.

FIG. 1 shows an overall system diagram of a transmission apparatus according to the present invention. A transmitter 1 having an input section 2, a separating circuit section 3, a modulator 4 and a transmitting section 5 separates a plurality of multiplexed input signals into first data strings D ₁ and second data strings D
₂ and a third data string, D _3, are output by the modulator 4 as a modulated signal from the transmitter 5, and the modulated signal is transmitted to the artificial satellite 10 by the antenna 6 through the transmission line 7.
This signal is received by the antenna 11 in the artificial satellite 10, amplified by the repeater 12, and transmitted to the earth again by the antenna 13.

The transmission radio waves are transmitted by the first receiver 23, the second receiver 33, and the third receiver 43 through the transmission paths 21, 31, and 41.
Sent to First, in the first receiver 23, input is made from the input unit 24 via the antenna 22, only the first data sequence is demodulated by the demodulator 25, and output from the output unit 26. In this case, the second data string and the third data string have no demodulation ability.

In the second receiver 33, the signal output from the input section 34 via the antenna 32 is converted to the first signal by the demodulator 35.
The data sequence and the second data sequence are demodulated, combined by the combiner 37 into one data sequence, and output from the output unit 36.

In the third receiver 43, the input from the antenna 42 enters the input unit 44 and the first data sequence
The three data strings of the second data string and the third data string are demodulated and combined into one data group by the combiner 47 and output from the output unit 46.

As described above, even if radio waves of the same frequency band are received from the same transmitter 1, the amount of information that can be received is different due to the difference in the performance of the demodulators of the above three receivers. With this feature, it is possible to simultaneously transmit compatible three pieces of information according to the performance to receivers having different performances in one radio band. For example, NTSC and HD of the same program
When transmitting three digital TV signals of a TV and a super-resolution HDTV, a super HDTV signal is separated into a low-frequency component, a high-frequency difference component, and a super-high-frequency difference component, each of which is a first data stream,
Corresponding to the second data string and the third data group, three types of compatible digital TV signals of medium resolution, high resolution, and ultra high resolution can be simultaneously broadcast in the frequency band of one channel.

In this case, an NTSC-TV signal can be demodulated by a small-valued demodulation receiver using a small antenna, an HDTV signal can be demodulated by a medium-size antenna capable of medium-value demodulation, and a multi-level demodulation using a large antenna can be performed. Such a receiver can receive an ultra-high resolution HDTV. To further explain FIG.
A digital transmitter 51 for performing TSC digital TV broadcasting receives only the same data as the first data group from an input unit 52, modulates the data with a modulator 54, and transmits the data to a transmitter 55 and an antenna 5
6, the signal is transmitted to the satellite 10 via the transmission path 57 and transmitted again to the earth via the transmission path 58.

In the first receiver 23, the demodulator 24 demodulates the received signal from the digital transmitter 1 into data corresponding to the first data sequence. Similarly, the second receiver 33 and the third receiver 43 demodulate a data group having the same content as the first data string. In other words, the three receivers are digital general TV
Digital broadcasting such as broadcasting can also be received.

Next, each part will be described. FIG. 2 shows the transmitter 1
It is a block diagram of.

The input signal enters the input section 2 and is separated by a separation circuit 3 into three digital signals of a first data string signal, a second data string signal, and a third data string signal.

For example, when a video signal is input, the low frequency component of the video signal is a first data sequence signal, the high frequency component of the video signal is a second data sequence signal, and the super high frequency component of the video signal is a third data sequence. Assigning to signals is conceivable. 3 isolated
The two signals are input to a modulation input unit 61 inside the modulator 4. Here, there is a signal point position modulation / change circuit 67 that modulates or changes the position of a signal point based on an external signal, and modulates or changes the position of the signal point according to the external signal.
In the modulator 4, amplitude modulation is performed on each of two orthogonal carrier waves to obtain a multilevel QAM signal. The signal from the modulation input unit 61 is sent to the first AM modulator 62 and the second AM modulator 63. one of the carrier from the carrier generator 64 of cos (2πf _c t) are AM modulated by the 1AM modulator 62 is sent to the combiner 65, another carrier sent to the [pi / 2 phase shifter 66 It is 90 ° are phase-shifted, is fed to the 2AM modulator 63 in the form of sin (2πf _c t), after being amplitude-modulated in the multi-level, in the combiner 65 is combined with the first 2AM modulated wave, transmission The signal is output by the unit 5 as a transmission signal. Since this method has been generally implemented conventionally, a detailed description of the operation will be omitted.

FIG. 3 shows a 16-value general QAM signal spectrum.
The operation will be described using the first quadrant of the source diagram. Strange
All signals generated by the modulator 4 are composed of two orthogonal carrier waves.
Acos2πf_ct vector 81 and Bsin2πf_ct vector 82
Can be represented by a composite vector of the two vectors. 0 points
Defining the tip of the combined vector as a signal point, 16 values
For QAM a₁, A_Two, A_Three, A_FourQuaternary amplitude value and b₁,
b_Two, B_Three, B_FourSum of the four amplitude values
16 signal points can be set. In the first quadrant of FIG.
C at point 83₁₁, C at signal point 84₁₂, Signal point 85 C_{twenty two},
C at signal point 86 _{twenty one}There are four signals:

[0030] C ₁₁ is a composite vector of a vector 0-a ₁ and a vector _{0-b 1, C 11 =} a 1 cos2πf c t-b 1 sin2πf
to become _{c t = Acos (2πf c t} + dπ / 2).

Here, 0-a ₁ on the rectangular coordinates in FIG.
A ₁ the distance between, a ₁ -a ₂ between the A _2, 0-b ₁ between the B _1, b
Between ₁ -b ₂ is defined as B _2, shown on the diagram.

As shown in the overall vector diagram of FIG. 4, there are a total of 16 signal points. Therefore, by associating each point with 4-bit information, 4-bit information transmission becomes 1
This is possible during a period, that is, one time slot.

FIG. 5 shows an example of general assignment when each point is expressed in a binary system. Of course, the greater the distance between each signal point, the easier it is for the receiver to distinguish. Therefore, in general, the arrangement is such that the distance between the signal points is as far as possible. If the distance between specific signal points is reduced,
In the receiver, it becomes difficult to distinguish between the two points, and the error rate deteriorates. Therefore, it is generally said that it is desirable to arrange them at equal intervals as shown in FIG. Therefore 16QA
In the case of M, the arrangement of signal points where A1 = A2 / 2 is generally implemented.

In the case of the transmitter 1 of the present invention, first, data is divided into a first data string and a second data string, or a third data string. Then, as shown in FIG. 6, the 16 signal points or signal point groups are divided into four signal point groups, and the four data of the first data string are first allocated to each signal point group. That is, when the first data string is 11, one of the four signal points of the first signal point group 91 in the first data quadrant is transmitted, and when the first data string is 01, the second signal point group 92 in the second quadrant is transmitted. , 00, the third signal point group 93, 10 in the third quadrant
In this case, one signal point is selected from the four signal points in the fourth signal point group 94 in the fourth quadrant according to the value of the second data string and transmitted. Next, in the case of 16 QAM, 2 bits of the second data string, 4-value data, and in the case of 64-value QAM, 4 bits
It, 16-level data is allocated to four signal points or sub-signal point groups in each of the divided signal point groups 91, 92, 93, and 94 as shown in FIG. All quadrants are targeted. Assignment of signal points to 91, 92, 93, and 94 is preferentially determined by 2-bit data of the first data group. Thus, 2 bits of the first data string and 2 bits of the second data string
Can be transmitted completely independently. The first data string can be demodulated even by a 4PSK receiver if the antenna sensitivity of the receiver is equal to or more than a certain value. If the antenna has higher sensitivity, both the first data group and the second data group can be demodulated by the modified 16QAM receiver of the present invention.

FIG. 8 shows an example of allocation of two bits of the first data string and two bits of the second data string.

In this case, the HDTV signal is divided into a low-frequency component and a high-frequency component, and a low-frequency video signal is allocated to the first data sequence and a high-frequency video signal is allocated to the second data sequence.
In the PSK receiving system, the NTSC equivalent video of the first data stream can be reproduced, and in the 16 QAM or 64 QAM receiving system, both the first data stream and the second data stream can be reproduced, and these are added to obtain an HDTV video. be able to.

However, if the distance between signal points is made equal as shown in FIG. 9, there is a threshold distance between the hatched portion in the first quadrant as viewed from the 4PSK receiver. If the threshold distance is A _TO and only 4PSK is sent, the amplitude of A _TO is sufficient. But which is the required amplitude of 3A _TO i.e. 3 times when you send 16QAM while maintaining A _TO.
That is, nine times as much energy is required as when transmitting 4PSK. Sending 4PSK signal points in 16QAM mode without any consideration is inefficient in power use. Regeneration of the carrier wave also becomes difficult. The power available for satellite transmission is limited. Such a system with poor power utilization efficiency is not practical until the transmission power of the satellite increases. 4PSK when digital TV broadcasting starts in the future
It is expected that a large number of receivers will be available. Once spread, it can be said that it is impossible to increase these receiving sensitivities because of the problem of receiver compatibility. Therefore,
The transmission power in the 4PSK mode cannot be reduced. Therefore 16
When transmitting a pseudo 4PSK signal point in the QAM mode, it is expected that a method of lowering the transmission power than the conventional 16QAM is required. Otherwise, transmission will not be possible with limited satellite power.

The features of the present invention are shown in FIG.
The point is that the transmission power of the quasi-4PSK type 16QAM modulation can be reduced by increasing the distance between the 94 divided signal point groups.

Here, in order to clarify the relationship between the receiving sensitivity and the transmission output, returning to FIG. 1, the receiving method of the digital transmitter 51 and the first receiver 23 will be described.

First, the digital transmitter 51 and the first receiver 2
A general transmission device 3 performs data transmission or video transmission including broadcasting. As shown in FIG. 7, the digital transmitter 51 is a 4PSK transmitter, which is obtained by removing the AM modulation function from the multilevel QAM transmitter 1 described in FIG. The input signal is input to the modulator 54 via the input unit 52. In the modulator 54, the modulation input unit 121 divides the input signal into two signals and performs first phase modulation on the reference carrier.
-2 phase modulation circuit 122 and a 2-2 phase modulation circuit 123 for modulating a carrier having a 90 ° phase difference from the reference carrier.
And these phase modulated waves are synthesized by a synthesizer 65,
Transmitted by the transmission unit 55.

FIG. 18 shows a modulated signal space diagram at this time. In general, it is common practice to set four signal points and make the distance between signal points equal to increase the power use efficiency. As an example, a case where signal point 125 is defined as (11), signal point 126 is defined as (01), signal point 127 is defined as (00), and signal point 128 is defined as (10). In this case, in order for the first receiver 23 of 4PSK to receive satisfactory data, the output of the digital transmitter 51 is required to have a certain amplitude value or more. Referring to FIG. 18, the first receiver 23 needs the minimum amplitude value of the transmission signal, ie, 0-a _{1, which} is the minimum necessary for receiving the signal of the digital transmitter 51 at 4PSK.
If the distance between them is defined as A _TO , the first receiver 23 can receive if the signal is transmitted at the minimum amplitude A _{TO of the} transmission limit or more.

Next, the first receiver 23 will be described. First
The receiver 23 receives the transmission signal from the transmitter 1 or the 4PSK transmission signal from the digital transmitter 51 via the repeater 12 of the satellite 10 with the small antenna 22, and the demodulator 24 converts the reception signal into a 4PSK signal. And demodulate. The first receiver 23 is originally a 4P of the digital transmitter 51.
It is designed to receive SK or 2PSK signals and to receive signals such as digital TV broadcasting and data transmission.

FIG. 19 is a block diagram showing the construction of the first receiver. The radio wave from the satellite 12 is received by the antenna 22. After this signal is input from the input unit 24, the carrier recovery circuit 131 and the π / 2 phase shifter 132 A carrier wave and a quadrature carrier wave are reproduced by the first phase detection circuit 133 and the second phase detection circuit 1 respectively.
34, the orthogonal components are detected independently of each other. The timing wave extracting circuit 135 independently detects each component for each time slot. The first and second discriminating circuits 136 and 137 detect two independent components. The demodulated signal is demodulated into a first data string by a first data string reproducing unit 232, and output by an output unit 26.

Here, the received signal will be described with reference to the vector diagram of FIG. The signal received by the first receiver 23 on the basis of the 4PSK transmission radio wave of the digital transmitter 51 is a signal shown in FIG.
It can be represented by four signal points 1 to 154.

However, actually, the noise in the transmission path and the transmission system
The signal points received due to the amplitude distortion and phase distortion of
It is distributed in a certain range around the signal point. From signal point
If it is too far away, it will not be possible to determine
Data gradually increases and data is restored when a certain setting range is exceeded.
become unable. Set error level even in the worst case
To demodulate within the data rate, take the distance between adjacent signal points.
Good. This distance is 2A _ROIs defined. 4PSK limit
When signal input, signal point 151 is | 0-a in FIG._R1| ≧
A_R0, | 0-b_R1| ≧ A_R01st discrimination area 1 indicated by oblique lines
If you set the transmission system to enter 55, then transport
If the waves can be reproduced, they can be demodulated. Set antenna 22
The lowest radius value is r₀, The transmission output exceeds a certain level
, All systems can receive. In FIG.
The amplitude of the transmission signal is the 4PSK minimum reception amplitude of the first receiver 23.
Width value, A_R0Set to be. This transmission minimum amplitude
Value A _T0Is defined. This allows half of the antenna 22
Diameter r₀If it is above, even if the receiving condition is the worst, the first receiver
23 can demodulate the signal of the digital transmitter 51. The present invention
When receiving 16QAM and 64QAM, first reception
It is difficult for the machine 23 to regenerate the carrier. others
As shown in FIG. 25 (a), the transmitter 1 is (π / 4 + nπ /
2) Place 8 signal points at the angle position and transmit.
For example, a carrier wave can be reproduced by the quadrupling method. FIG.
As shown in (b), 16 signals are on the extension of the angle of nπ / 8.
If the signal point is arranged, the carrier recovery circuit 131 will be multiplied by 16
Signal points degenerate by adopting the carrier recovery method of
The carrier of the pseudo 4PSK type 16QAM modulated signal can be easily reproduced.
I can live. In this case A₁/ (A₁+ A_Two) = Tan (π /
8) If the signal point of the transmitter 1 is set and transmitted so that
Good. Here, consider the case of receiving a QPSK signal.
You. The signal point position modulation / change circuit 67 of the transmitter of FIG.
The signal point position is the signal point position of the QPSK signal shown in FIG.
Modulation such as AM can be superimposed on the position. In this case
1 The signal point position demodulation unit 138 of the receiver 23 calculates the position of the signal point.
Demodulate the modulated signal or position change signal by PM, AM, etc.
You. And outputs the first data string and demodulated signal from the transmission signal.
I do.

Next, returning to the transmitter 1, the 16PSK transmission signal of the transmitter 1 will be described with reference to the vector diagram of FIG. 9, as shown in FIG.
₁ larger than 4PSK minimum transmission output A _TO of the digital transmitter 51 of FIG. 18. Then, the signals at the signal points 83, 84, 85 and 86 in the first quadrant of FIG.
It enters the SK receivable area 87. When these signals are received by the first receiver 23, these four signal points fall into the first discrimination area of the reception vector diagram of FIG. Therefore, the first receiver 23 determines that the signal point is the signal point 151 in FIG. 20 regardless of whether any of the signal points 83, 84, 85, and 86 in FIG. 9 is received, and (11)
Is demodulated in this time slot. This data is (11) of the first divided signal point group 91 of the transmitter 1, that is, (11) of the first data string, as shown in FIG. The first data string is similarly demodulated in the second, third, and fourth quadrants. That is, the first receiver 23 demodulates only the 2-bit data of the first data string among the plurality of data strings of the modulation signal from the 16 QAM, 32 QAM, or 64 QAM transmitter 1.
In this case, since the signals of the second data string and the third data string are all included in the first to fourth divided signal point groups 91, the signal of the first data string is not affected. However, it has an effect on the reproduction of the carrier wave, so that the following measures are required.

If there is no limit to the output of the satellite transponder, the conventional signal point equidistant system shown in FIG.
It can be realized by 64QAM. However, as described above, unlike terrestrial transmission, in satellite transmission, the launch cost increases significantly as the weight of the satellite increases. Therefore, the transmission output is restricted by the output limit of the repeater of the main body and the power limit of the solar cell. This situation will continue for some time unless the launch cost of the rocket is reduced by technological innovation. The transmission output is about 20 W for a communication satellite and about 100 W to 200 W for a broadcast satellite. Therefore, the 16QA signal point equidistant method shown in FIG.
When trying to transmit 4PSK at M, the amplitude of 16QAM is 2A ₁ = A ₂ , so 3A _{TO is} required, which is required 9 times in terms of power. 4PSK for compatibility
Requires nine times the power. Also, when trying to make the first receiver of 4PSK also receivable with a small antenna, at present,
It is difficult to obtain such output with the planned satellite. For example, a system of 40 W requires 360 W and cannot be realized economically.

Here, when it is considered that all the receivers have the same size antenna, it is possible to obtain the same area signal point system efficiency with the same transmission power. However, a new transmission system can be configured by considering a system in which receiver groups of antennas having different sizes are combined.

More specifically, 4PSK increases the number of recipients by allowing reception with a simple and low-cost receiving system using a small antenna. Next, 16QAM is a high-performance but high-cost multi-level demodulation receiving system that uses a medium-sized antenna, receives high-value-added services such as HDTV that matches the investment, and limits the target to specific recipients. To establish. In this way, 4PSK and 16QAM, and in some cases, 64DMA can be transmitted hierarchically by slightly increasing the transmission output.

For example, by setting the signal point interval so that A1 = A2 as shown in FIG. 10, the total transmission output can be reduced. Amplitude A (4) for transmitting this case 4PSK can be expressed by a vector 95, the 2A ₁ ² of the square root. The total amplitude A (16) can be represented by a vector 96 (A
₁ + A ₂ ) ² + (B ₁ + B ₂ ) ² .

[0051] ^{| A (4) | 2 =} A 1 2 + B 1 2 = A TO 2 + A TO 2
= 2A _TO ² | A (16) | ² = (A ₁ + A ₂ ) ² + (B ₁ + B ₂ ) ² = 4A
_TO ² +4 A _TO ² = 28 A _{T O} ² | A (16) | / | A (4) | = 2 That is, transmission can be performed with twice the amplitude and four times the transmission energy in the case of transmitting 4PSK. By can not demodulate variations 16 QAM is a common receiver for transmitting at equidistant signal points set in advance the two thresholds A ₁ and A ₂ second
It can be received by the receiver 33. For Figure 10, the shortest distance between the signal points in the first division signal point group 91 is A _1, 4PS
Compared to signal point distance 2A ₁ of K A ₂ / 2A ₁ becomes. A ₁
= From A ₂ becomes the distance between the half of the signal points, in order to obtain a same error rate twice the reception sensitivity of the amplitude, it is necessary to receive sensitivity of four times the energy. To obtain 4 times the receiver sensitivity, if the radius r ₂ of the antenna 32 of the second receiver 33 twice i.e. r ₂ = 2r ₁ as compared to the radius radius r ₁ of the antenna 22 of the first receiver 23 Good. For example, if the antenna of the first receiver 23 has a diameter of 30 cm, this can be realized by setting the antenna diameter of the second receiver 33 to 60 cm. As a result, by demodulating the second data string and allocating it to the high frequency component of HDTV, a new service such as HDTV can be performed on the same channel. Since the service content is doubled, the receiver can receive the service corresponding to the investment of the antenna and the receiver. Therefore, the cost of the second receiver 33 may be higher. Here, since the minimum transmission power is determined for the 4PSK mode reception, A in FIG.
Modification 1 for transmission power of 4PSK by ratio of ₁ and A ₂
The transmission power ratio n _{16 of} 6APSK and the antenna radius r ₂ of the second receiver 33 are determined.

When calculating to measure this optimization, 4
The minimum required transmission energy of PSK is {(A ₁ + A ₂ ) /
A ₁ } ² times If this is defined as n ₁₆ , the distance between signal points when receiving with modified 16-value QAM is A ₂ , the distance between signal points when receiving with 4 PSK is 2A ₁ , and the ratio of the distance between signal points Is A ₂ / 2A, so if the radius of the receiving antenna is r ₂ , the relationship is as shown in FIG. Curve 101 is the transmission energy magnification n ₁₆ and the radius r of the antenna 22 of the second receiver 23.
₂ represents the relationship.

Point 102 is 16QA for equidistant signal points
In the case of transmitting M, the transmission energy is required to be nine times as described above, which is not practical. From FIG. 11, it can be seen from the graph that the antenna radius r ₂ of the second receiver 23 does not become so small even if n ₁₆ is increased by 5 times or more.

In the case of a satellite, the transmission power is limited,
Cannot exceed a certain value. From this, it becomes clear that n16 is desirably 5 times or less. This area is shown by the hatched area 103 in FIG. For example, within this area, for example, the point 104 has transmission energy four times and the antenna radius r ₂ of the second receiver 23 doubles. At the point 105, the transmission energy is doubled, and r ₂ is approximately five times. These are in a range that can be put to practical use.

When the fact that n ₁₆ is smaller than 5 is expressed by A ₁ and A ₂ , n ₁₆ = ((A ₁ + A ₂ ) / A ₁ ) ² ≦ 5 A ₂ ≦ 1.23A ₁ FIG. the distance between 2A (4), when the maximum Fuhaba 2A (16), a (4 ) and a (16) -A (4) are a ₁ and a ₂
Therefore, it is sufficient to set {A (16)} ² ≦ 5 {A (14)} ^2. Next, an example using a modified 64APSK modulation will be described. The third receiver 43 can perform 64-level QAM demodulation.

The vector diagram of FIG. 12 shows a case where the divided signal point group of the vector diagram of FIG. 10 is increased from four values to 16 values. In the first divided signal point group 91 of FIG.
Signal points of 4 × 4 = 16 values starting from 0 are arranged at equal intervals. In this case, the transmission amplitude must be set to A ₁ ≧ A _TO in order to have compatibility with 4PSK.
Assuming that the radius of the antenna of the third receiver 43 is r ₃ ,
The value of r ₃ when defined as output signal n64, when determined in the same manner ^{_{r 3 2 = {6 2 /}} (n-1)} r 1 2 , and the radius r ₃ in FIG. 13 64 value QAM - Output multiple It becomes a graph like n.

However, in the arrangement as shown in FIG. 12, when the signal is received by the second receiver 33, only 2 bits of 4PSK can be demodulated, so that the first, second and third compatibility must be satisfied by the second reception. It is desirable that the device 33 have a function of demodulating the modified 16-level QAM from the modified 64-level QAM modulated wave.

As shown in FIG. 14, the compatibility of the three receivers is established by grouping the signal points of three layers. Explaining only in the first quadrant, it has been stated that the first divided signal point group 91 is assigned 2-bit (11) of the first data string.

Next, the first sub-divided signal point group 181 has the second
2 bits (11) of the data string are allocated. (01) is assigned to the second sub-divided signal point group 182, (00) is assigned to the third sub-divided signal point group 183, and (10) is assigned to the fourth sub-divided signal point group 184. This is equivalent to FIG.

The signal point arrangement of the third data string will be described in detail with reference to the vector diagram of the first quadrant in FIG. 15, for example, the signal points 201, 205, 209, and 213 are (11), and the signal points 202, 206, 210, and 214 to (01), signal point 2
03, 207, 211 and 215 to (00), signal point 20
If 4,208,212,216 is (10), the third
The 2-bit data of the data string can be transmitted independently of the first data and the second data, and the 3-bit 2-bit data can be transmitted independently.

In addition to sending 6-bit data, the present invention is characterized by three levels of different performance receivers.
It is possible to transmit data of different transmission amounts of bit, 4 bits, and 6 bits, and to achieve compatibility between the transmissions of the three layers.

Here, a method of arranging signal points necessary for achieving compatibility during three-layer transmission will be described.

As shown in FIG. 15, first, in order for the first receiver 23 to receive the data of the first data string, A ₁
It has already been mentioned that ≧ A _TO .

Next, the signal point of the second data string, for example, FIG.
The signal point 91 of FIG.
It is necessary to secure a distance between signal points so that the signal points can be distinguished from 3,184 signal points.

FIG. 15 shows a case where the distance is 2/3 A ₂ . In this case the signal between point distance of the internal signal points 201 and 202 of the first sub-division signal point group 181 becomes A _2/6. Third
The reception energy required for reception by the receiver 43 is calculated. In this case, assuming that the radius of the antenna 32 is r ₃ ,
Required transmission energy is 4PSK transmission energy n _{6 4}
When defined as a ^{_{multiplication, r 3 2 = (12r 1}} ) become This graph ² / (n-1) represented by the curve 221 in FIG. 16. For example, in the case of the points 222 and 223, the first, second, and third data are obtained by using the antenna having the radius of 8 times if the transmission energy of 6 times the 4PSK transmission energy is obtained, or by using the antenna of 6 times if the transmission energy is 9 times. It can be seen that the columns can be demodulated.
In this case, the distance between the signal point of the second data string 2 / 3A ₂ to approach for ^{_{r 2 2 = (3r 1)}} 2 / (n-1) becomes the curve 2
It is necessary to slightly increase the size of the antenna 32 of the second receiver 33 as shown in FIG.

In this method, the first data string and the second data string are transmitted while the transmission energy of the satellite is small as of the present time, and the first receiver 23 and the second receiver 23 will be transmitted in the future when the transmission energy of the satellite is greatly increased. The third data stream can be sent without damaging the data received by the second receiver 33 and without any modification, and thus a great effect of both compatibility and developability can be obtained.

In order to explain the reception state, the second receiver 33 will be described first. The above-mentioned first receiver 23 originally has a radius r
The first data column of 4PSK modulation signal and the transmitter 1 of the digital transmitter 51 while is set so as to be demodulated by ₁ small antennas, as shown in FIG. 10 of the transmitter 1, the second receiver 33 16-value signal point, that is, 1 of the second data string
A 2-bit signal of 6QAM can be completely demodulated. A 4-bit signal can be demodulated together with the first data string. In this case, the ratio of A1 and A2 differs depending on the transmitter. This data is set by the demodulation control unit 231 in FIG. 21 and a threshold is sent to the demodulation circuit. This enables AM demodulation.

A block diagram of the second receiver 33 shown in FIG.
The block diagram of the first receiver 23 in FIG. 19 has almost the same configuration. The difference is that first, the antenna 32 has a larger radius r ₂ than the antenna 22. Therefore, a signal having a shorter signal point distance can be discriminated. Next, demodulator 3
5, a demodulation control unit 231 and a first data string reproducing unit 2
32 and a second data string reproducing unit 233. The first identification reproduction circuit 136 has an AM demodulation function for demodulating the modified 16QAM. In this case, each carrier has a quaternary value, and has a zero level and ± a binary threshold. In the case of the present invention,
Because of the modified 16QAM signal, the threshold value differs depending on the transmission output of the transmitter as shown in the signal vector diagram of FIG. Therefore,
When thread hold values were normalized to TH _16, FIG. 22
As apparent from the _{TH 16 = (A 1 + A} 2/2) / (A 1 + A 2).

[0069] demodulation information of the A1, A2 or TH _16, and the multilevel modulation values m, from the transmitter 1, is transmitted included in the first data stream. In addition, there is a method in which the demodulation control unit 231 statistically processes the received signal to obtain demodulation information.

Referring to FIG. 26, shift factor A ₁ / A ₂
A method of determining the ratio of the above will be described. Changing A ₁ / A ₂ changes the threshold. Error accordance A ₁ / A ₂ set at the receiver side moves away from the value of A ₁ / A ₂ set at the transmitter side will increase. The demodulated signal from the second data stream reproducing unit 233 shown in FIG. 26 is fed back to the demodulation control circuit 231 to control the shift factor A ₁ / A ₂ in the direction of decreasing the error rate, so that the third receiver 43 can shift the shift factor. A
_Since it is not necessary to demodulate ₁ / A ₂ , the circuit is simplified. In addition, the transmitter does not need to send A ₁ / A _2, which has the effect of increasing the transmission capacity. This can be used for the second receiver 33. The demodulation control circuit 231 includes a memory 231a
have. When a threshold value different for each TV broadcast channel, that is, a shift ratio, the number of signal points, and a synchronization rule is stored and the channel is received again, recalling this value has an effect that reception is fast and stable.

If the demodulation information is unknown, it becomes difficult to demodulate the second data string. This will be described below with reference to the flowchart of FIG.

Step 3 even if demodulation information cannot be obtained
Thirteen demodulation of 4PSK and the demodulation of the first data string in step 301 can be performed. Therefore, in step 302, the demodulation information obtained by the first data string reproducing unit 232 is
Send to 1. The demodulation control unit 231 determines in step 303 that m is 4
Or 2 if 4PSK or 2PSK in step 313
Is demodulated. If NO, m is 8 or 1 in step 304
If it is 6, go to step 305. If no, step 3
Go to 10. In step 305, calculations of TH8 and TH16 are performed. In step 306, the demodulation control unit 231 sends the threshold value TH16 for AM demodulation to the first identification reproduction circuit 136 and the second identification reproduction circuit 137. In steps 307 and 315, demodulation of the modified 16QAM and reproduction of the second data string are performed. In step 308, the error rate is checked. If the error rate is not good, the process returns to step 313 to perform 4PSK demodulation.

In this case, signal point 85.83 in FIG.
Is on the angle cos (ωt + nπ / 2), but signal point 84.86 is not on this angle. Therefore, the second data stream reproducing unit 233 shown in FIG. 21 sends carrier wave transmission information of the second data stream to the carrier wave reproducing circuit 131 so that the carrier wave is not extracted from the signal at the timing of the signal point 84.86.

The transmitter 1 intermittently sends a carrier timing signal based on the first data sequence on the assumption that the second data sequence cannot be demodulated. Even if the second data string cannot be demodulated by this signal, the signal point 83.
85 is known. Therefore, the carrier can be reproduced by sending the carrier wave transmission information to the carrier reproducing circuit 131.

Next, when a signal of the modified 64QAM as shown in FIG. 23 is transmitted from the transmitter 1, returning to the flowchart of FIG. 24, it is determined at step 304 whether m is not 16 and at step 310, m is 64. Whether or not the following is checked, and if it is not the equidistant signal point method in step 311, the process proceeds to step 312. Here is the TH ₆₄ = the seek distance TH ₆₄ between signal points upon deformation _{64QAM (A 1 + A 2/} 2) / (A 1 + A 2), the same as the TH _16. However, the distance between signal points becomes smaller.

Assuming that the distance between signal points in the first sub-divided signal point group 181 is A ₃ , the first sub-divided signal point group 181
And the distance between the second sub-divided signal point group 182 and (A ₂ -2A ₃ )
When normalized, (A ₂ -2A ₃ ) / (A ₁ + A ₂ ). If this is defined as d ₆₄ , if d ₆₄ is equal to or less than the discrimination capability T ₂ of the second receiver 33, it cannot be discriminated. In this case, determination is made in step 313. If d ₆₄ is out of the allowable range, the process enters the 4PSK mode in step 313. If it is within the discrimination range, the process proceeds to step 305, and 16QAM of step 307 is performed.
Is demodulated. If the error rate is high in step 308, the process enters the 4PSK mode in step 313.

In this case, if the transmitter 1 transmits the modified 8QAM signal of the signal point as shown in FIG. 25A, all the signal points are on the angle of cos (2πf + n · π / 4). By the quadruple circuit, all carriers are degenerated to the same phase, so that the effect of simplifying the reproduction of the carrier is produced. In this case, 2 bits of the first data string can be demodulated even by the 4PSK receiver, which is not considered, and the second receiver 33
Then, the second data string 1b FIGS. 25 (a) and 25 (b)
The signal point arrangement diagram of FIG. 3 shows C-CDM signal points when signal points shifted in the polar coordinate direction (r, θ) are added. The C-CDM in which the signal point is shifted in the orthogonal coordinates, that is, in the XY directions, is referred to as the orthogonal coordinate system C-CDM, and the C-CDM in which the signal points are shifted in the polar coordinate system, that is, the r and θ directions.
Is referred to as a polar coordinate system C-CDM.

First, the signal point arrangement diagram of 8PS-APSK in FIG. 25A is obtained by adding another signal point shifted in the direction of the radius r in the polar coordinates to each of the four signal points of QPSK. Thus, the polar coordinate C-CDM having eight signal points from QPSK as shown in FIG.
APSK is realized. This is the polar (P
ole), and is referred to as SP-APSK for Shortened Pole-APSK because it is an APSK to which a signal point shifted from ole) is added. In this case, it coordinates the definition of the signal point 85 is added to QPSK by using a shift factor S ₁ as shown in FIG. 139. The signal point of 8PS-APSK is a signal point ((S) at a position obtained by shifting the signal point 83 of the standard QPSK polar coordinates (r ₀ , θ ₀ ) by S ₁ r _{0 in the} radius r direction.
₁ +1) r ₀ , θ ₀ ). Thus Q
Sub-channel 2 of 1 bit is added to sub-channel 1 of 2 bits same as PSK.

FIG. 140 shows a constellation diagram.
As shown, the coordinates (r₀, Θ₀), (R₀+ S₁r₀, Θ₀)
Are shifted by S2ro in the radius r direction to the eight signal points
(R)₀+ S_Twor₀,
θ₀) And (r₀+ S₁r₀+ S_Twor ₀, Θ₀) 1-bit message
Number points are added. This is 1b
The subchannel of it is obtained. This is 16PS-A
Called PSK, 2 bit subchannel 1 and 1 bit
Sub-channel 2 and 1-bit sub-channel 3
One. 16-PS-APSK also has θ = 1/4 (2n + 1) π
The normal QPSK described in FIG.
Since the carrier can be recovered by the receiver, the second sub-channel is
Demodulation cannot be performed, but the first subchannel of 2 bits is demodulated.
Wear. The C-CDM method shifting in the polar coordinate direction in this way
The formula is Q, which is the mainstream in PSK, especially in current satellite broadcasting.
Expansion of transmission information volume while maintaining compatibility with PSK receiver
It has the effect of turning off. For this reason, the first generation using PSK
Second generation APS without losing satellite viewers
Compatible with multi-level modulation using K for satellite broadcasting with a large amount of information
Can be expanded while maintaining

The signal point in the case of FIG. 25B is on the angle = π / 8 in polar coordinates. This is limited to four signal quadrants of 16PSK, that is, three signal quadrants out of a total of 16 signal points, that is, 12 signal points. By limiting, when viewed roughly, these three signal points can be regarded as one signal point and can be regarded as four QPSK signal points in total. Thus, QPSK is performed in the same manner as described above.
The first sub-channel can be reproduced using the receiver.

These signal points are θ = π / 4, θ = π / 4
+ Π / 8 and θ = π / 4−π / 8.
That is, a signal point obtained by shifting the signal point of QPSK on the angle π / 4 by ± π / 8 in the angle direction of the polar coordinate is added. Since it is in the range of θ = π / 4 ± π / 8, it can be regarded as substantially one signal point on θ = π / 4 of θPSK. In this case, the error rate slightly deteriorates, but Q shown in FIG.
Since the PSK receiver 23 can discriminate the signal point from the signal points on four angles, it can be demodulated and 2-bit data is reproduced.

In the case of the angle shift C-CDM, the angle is π /
When it is above n, the carrier recovery circuit can recover the carrier by the n-multiplier circuit as in the other embodiments. Also, π / n
If not, the carrier can be reproduced by sending several pieces of carrier information in a certain period as in the other embodiments.

As shown in FIG. 141, if the angle in polar coordinates between the signal points of QPSK or 8-SP-APSK is 2θ ₀ and the primary angle shift factor is P ₁ , the signal point is divided into two points. By shifting by ± P ₁ θ _{0 in the} θ direction, the signal is divided into two signal points of (r ₀ , θ ₀ + P ₁ θ ₀ ) and (r ₀ , θ ₀ −P ₁ θ ₀ ) in the case of QPSK. The number of points is doubled. Thus, a 1-bit sub-channel
3 is added. This is referred to as 8-SP-PSK of P = P _1. As shown in FIG. 142, the one obtained by adding the signal points obtained by shifting the signal points of 8-SP-PSK by S ₁ r ₀ in the radius r direction is called 16-SP-APSK (P, S ₁ type). Subchannel 1.2 can be reproduced by 8PS-PSK having the same phase. Now, return to FIG. 25B. C-CDM using the angle shift of the polar coordinate system is shown in FIG.
Since it can be applied to PSK as in 41, it can also be used for first generation satellite broadcasting. However, the second generation AP
When used in SK satellite broadcasting, the polar coordinate system C-CDM cannot make the intervals between signal points in a group uniform as shown in FIG. Therefore, power use efficiency is poor. On the other hand, C-CDM at the time of rectangular coordinates is not well compatible with PSK.

The method shown in FIG. 25B is compatible with both the rectangular coordinate system and the polar coordinate system. Since the signal points are arranged at an angle of 16 PSK, the signal points can be demodulated by 16 PSK, and since the signal points are grouped, demodulation can be performed by the QPSK receiver. In addition, demodulation can be performed even by 16-SRQAM since the antenna is also arranged on orthogonal coordinates. QPSK, 16P
This is a method that has a great effect that it can be extended while realizing compatibility between the polar coordinate system among the three of SK and 16-SRQAM and the rectangular coordinate system C-CDM. It is possible to play back a total of 3 bits.

Next, the third receiver 43 will be described. FIG.
6 is a block diagram of the third receiver 43, which has almost the same configuration as the second receiver 33 of FIG. The difference is that the third data string reproducing unit 234 is added and that the identification reproducing circuit has eight-level discrimination ability. Radius r _{3 of} antenna 42
Is larger than r _2, so that a signal having a shorter distance between signal points, for example, a 32-level QAM or a 64-level QAM can be demodulated. Therefore, in order to demodulate 64-value QAM, it is necessary for the first discriminating / reproducing circuit 136 to discriminate an 8-level level from the detection signal wave. In this case, there are seven threshold levels. Since one of them is 0, there are three thresholds in one quadrant.

As shown in the signal space diagram of FIG. 27, there are three thresholds in the first quadrant.

As shown in FIG. 27, there are three normalized thresholds, TH1 ₆₄ , TH2 ₆₄ and TH3 ₆₄ .

[0088] _{TH1 64 = (A 1 + A} 3/2) / (A 1 + A 2) TH2 64 = (A 1 + A 2/2) / (A 1 + A 2) TH3 64 = (A 1 + A 2 -A 3 / 2) / (A ₁ + A ₂ ).

By demodulating the received signal subjected to phase detection with this threshold value, the data of the third data sequence is demodulated in the same manner as the first data sequence and the second data sequence described with reference to FIG. As shown in FIG. 23, the third data string is, for example, the first data string.
Four signal points 201 and 20 in sub-divided signal group 181
By discriminating 2, 203 and 204, 4 values, that is, 2 bits
I can take it. Thus, demodulation of 6 bits, that is, modified 64-value QAM is enabled.

At this time, the demodulation control section 231 knows the values of m, A ₁ , A ₂ , and A _{3 from} the demodulation information included in the first data string of the first data string reproducing section 232, and thus the threshold value TH is obtained.
1 ₆₄ and TH2 ₆₄ and TH3 feed ₆₄ and first regenerator circuit 136 calculates the to the second regenerator circuit 137, deformation 64QA
M demodulation can be performed reliably. In this case, since the demodulated information is scrambled, it is possible to make it possible for only a permitted receiver to demodulate 64QAM.
FIG. 28 shows a flowchart of the demodulation control section 231 of the modified 64QAM. Only the differences from the 16-value QAM flowchart of FIG. 24 will be described. Step 304 in FIG.
Then, step 320 is reached. If m = 32, step 322 is reached.
Is demodulated. If NO, m in step 321
= 64 or determined, since A ₃ can not be reproduced from the set value or less in step 323, towards the step 305, the same flow chart as in FIG. 24, demodulates the deformation 16QAM. Here, returning to step 323, if A ₃ is equal to or greater than the set value, the threshold is calculated in step 324, and
At step 25, the three threshold values are sent to the first and second discrimination / reproduction circuits, and at step 326, reproduction of the modified 64QAM is performed.
At 27, the first, second, and third data are reproduced. At step 328, if the error rate is high, the flow proceeds to step 305, and 16QAM demodulation is performed. If the error rate is low, 64QAM demodulation is continued.

Here, a carrier recovery method important for demodulation will be described. The present invention uses modified 16QAM and modified 64QA.
One of the features is that the first data string of M is reproduced by the 4PSK receiver. In this case, when a normal 4PSK receiver is used, it is difficult to reproduce the carrier wave and normal demodulation cannot be performed. To prevent this, some countermeasures are required on the transmitter side and the receiver side.

There are two methods according to the present invention. The first method is intermittent (2n-1)
This is a method of sending signal points on an angle of π / 4. The second method is a method in which substantially all signal points are arranged and transmitted on an angle of nπ / 8.

In the first method, as shown in FIG. 38, the signal points at four angles, π / 4, 3π / 4, 5π / 4, and 7π / 4, for example, the signal points 83 and 85 38, the synchronous time slots 452, 453, 454, and 455, which are intermittently transmitted in the time slot group 451 in the time chart of the transmission signal in FIG. 38, are set based on a certain rule. I do. Then, during this period, one of the eight signal points on the angle is always transmitted. In other time slots, an arbitrary signal point is transmitted. Then, the transmitter 1 arranges the above rule for transmitting the time slot in the data synchronization timing information section 499 shown in FIG. 41 and transmits the data.

The contents of the transmission signal in this case will be described in more detail with reference to FIG.
Time slot group 451 including 453, 454, 455
Form one unit data string 491, Dn.

Since the synchronization time slots are intermittently arranged in this signal based on the rules of the synchronization timing information, if the arrangement rules are understood, the carrier wave can be easily reproduced by extracting the information in the synchronization time slots. it can.

On the other hand, at the beginning of the frame of the data sequence 492, there is a synchronization area 493 indicated by S, which is composed of only synchronization time slots indicated by oblique lines. With this configuration, the amount of extracted information for carrier wave reproduction increases,
There is an effect that the carrier wave of the SK receiver can be surely and quickly reproduced.

The synchronization area 493 includes S1, S2, S3
, 498, 497, 498, etc., which contain a unique word for synchronization and the demodulation information described above. There is also a phase synchronization signal arrangement information section 499 indicated by I _T , which contains information such as information on arrangement intervals of the phase synchronization time slots and information on arrangement rules.

[0098] Since the carrier for the signal point has only a particular phase region of the phase synchronization time slot can be played on 4PSK receiver, since the content of the phase synchronization unit arranged information I _T is capable of reliably reproduce, after the information obtained Can reliably reproduce the carrier.

Next to the synchronization area 493 in FIG. 41, there is a demodulation information section 501, which contains demodulation information relating to a threshold voltage necessary for demodulating a modified multi-level QAM signal.
Since this information is important for demodulation of multi-level QAM, if demodulation information 502 is placed in the synchronization area as in the synchronization area 502 in FIG. 41, the demodulation information can be obtained more reliably.

FIG. 42 is a signal arrangement diagram when a burst signal is transmitted by the TDMA method. The difference from FIG. 41 is that a guard time 521 is provided between the data strings 492 and Dn and other data strings, and no transmission signal is transmitted during this period. A synchronization section 522 for synchronization is provided at the head of the data sequence 492. During this period, only the signal points having the phase of (2n-1) π / 4 are transmitted. Therefore, a carrier wave can be reproduced even by a 4PSK demodulator.
Thus, synchronization and carrier wave reproduction can be performed even in the TDMA system.

Next, the carrier recovery system of the first receiver 23 in FIG. 19 will be described in detail with reference to FIGS. 43 and 44. The received signal input in FIG. 43 enters the input circuit 24,
One of the demodulated signals synchronously detected by the synchronous detection circuit 541 is sent to the output circuit 542 and output, and the first data string is reproduced. The phase synchronization section arrangement information section 499 of FIG. 41 is reproduced by the extraction timing control circuit 543, and it is known at which timing the signal of the (2n-1) π / 4 phase synchronization section comes in. Phase synchronization control signal 56
1 is sent. The demodulated signal is sent to the multiplication circuit 545,
The frequency is multiplied and sent to the carrier recovery control circuit 54. FIG.
The signal 562 includes a signal of the true phase information 563 and a signal other than the signal 562 like the signal 562 of FIG. As shown by hatching in the timing chart 564, a phase synchronization time slot 452 including signal points having a phase of (2n-1) π / 4 is intermittently included. This is sampled by the carrier reproduction control circuit 544 using the phase synchronization control signal 564 to obtain a phase sample signal 565. By sampling and holding this, a predetermined phase signal 566 is obtained. This signal passes through the loop filter 546, and the VCO 5
The carrier wave is sent to 47 and reproduced, and sent to the synchronous detection circuit 541. In this manner, signal points having a phase of (2n-1) π / 4 as shown by oblique lines in FIG. 39 are extracted. Based on this signal, an accurate carrier wave can be reproduced by the quadrupling method. At this time, a plurality of phases are reproduced, but by inserting a unique word into the synchronization section 496 in FIG. 41, the absolute phase of the carrier can be specified.

When transmitting the modified 64QAM signal as shown in FIG. 40, the phase synchronization time slot 452 and the phase synchronization time slot 452 are only applied to signal points in the phase synchronization area 471 indicated by oblique lines having a phase of approximately (2n−1) π / 4. The transmitter sends 452b and the like. For this reason, a carrier cannot be reproduced by a normal 4PSK receiver, but the first receiver 23 of 4PSK has an effect that the carrier can be reproduced by providing the carrier recovery circuit of the present invention.

The above is the case where the carrier recovery circuit of the Costas system is used. Next, a case where the present invention is used in an inverse modulation type carrier recovery circuit will be described.

FIG. 45 shows an inverse modulation type carrier recovery circuit of the present invention. The demodulated signal is reproduced by the synchronous detection circuit 541 from the received signal from the input circuit 24. On the other hand, the input signal delayed by the first delay circuit 591 is input to the four-phase modulator 5.
At 92, the signal is inversely demodulated by the demodulated signal to become a carrier signal. The carrier signal that has passed through the carrier recovery control circuit 544 is sent to the phase comparator 593. On the other hand VCO
The reproduced carrier from 547 is supplied to the second delay circuit 594 by the
The phase is compared with the above-mentioned inversely modulated carrier signal by the phase comparator 593, the phase difference signal is supplied to the VCO 547 through the loop filter 546, and the carrier having the same phase as the received carrier is reproduced. In this case, similarly to the Costas-type carrier recovery circuit of FIG.
43 samples the phase information of only the signal points in the hatched area in FIG.
However, the carrier can be reproduced by the 4PSK modulator of the first receiver 23.

Next, a description will be given of a method of reproducing a carrier by a 16-times multiplication method. Transmitter 1 in FIG. 2 performs modulation and transmission by arranging signal points of modified 16QAM at a phase of nπ / 8 as shown in FIG. First receiver 2 in FIG.
In the case of No. 3, by using a Costas type carrier recovery circuit having a 16 multiplication circuit 661 as shown in FIG.
The carrier can be regenerated. 4 by the 16-multiplier circuit 661.
A signal point having a phase of nπ / 8, such as 6, is degenerated to the first quadrant, so that the carrier can be reproduced by the loop filter 546 and the VCO 541. By arranging the unique word in the synchronization area, the absolute phase can be extracted from the 16 phases.

Next, the configuration of the 16 multiplication circuit will be described. From the demodulated signal, a sum signal,
A difference signal is created and multiplied by a multiplier 664 to obtain cos2θ
Create The multiplier 665 produces sin2θ.
These are multiplied by a multiplier 666 to generate sin4θ.

Similarly, from sum2θ and cos2θ, sum circuit 667 difference circuit 668 and multiplier 670 provide s
Create in8θ. Con8θ is created by the sum circuit 671, the difference circuit 672, and the multiplier. Then, by making sin16θ by the multiplier 674, 16 times multiplication can be performed.

According to the 16-times multiplication method described above, FIG.
There is a great effect that the carrier waves of all the signal points of the modified 16QAM signal having such a signal point arrangement can be reproduced without extracting a specific signal point.

A modified 64Q arranged as shown in FIG.
Although the carrier of the AM signal can be reproduced, some signal points are slightly shifted from the synchronization area 471, so that the error rate during demodulation increases.

As a countermeasure, there are two methods. One is to not transmit a signal at a signal point outside the synchronization area. This has the effect of reducing the amount of information but simplifying the configuration.
Another is to provide a synchronization time slot as described with reference to FIG. By transmitting signal points such as the synchronous phase regions 471 and 471a having a phase of nπ / 8 indicated by oblique lines during a synchronous time slot in the time slot group 451, accurate synchronization can be achieved during this period. Therefore, the phase error is reduced.

As described above, the modified 16QA by the 4PSK receiver has a simple receiver configuration by the 16 multiplication method.
There is a great effect that a carrier wave of a signal of M or modified 64QAM can be reproduced. Further, when a synchronization time slot is further set, an effect of increasing the phase accuracy at the time of carrier reproduction of the modified 64QAM can be obtained.

As described in detail above, by using the transmission apparatus of the present invention, a plurality of data can be simultaneously transmitted in a single radio band in a hierarchical structure.

In this case, by setting three levels of receivers having different reception sensitivities and demodulation capabilities for one transmitter, there is an advantage that the data amount commensurate with the investment of the receiver can be demodulated. First, a human receiver who purchases a small antenna and a low-resolution but low-cost first receiver can demodulate and reproduce the first data string. Next, a receiver who has purchased a medium-sized antenna and a medium-cost high-cost second receiver can reproduce the first and second data strings. A person who has purchased a large-sized antenna and a high-resolution third receiver having a high resolution can demodulate and reproduce all of the first, second, and third data strings.

If the first receiver is a digital satellite broadcast receiver for home use, the receiver can be realized at a low price that can be accepted by many general consumers. Although the second receiver initially requires a large antenna and is expensive, it is not acceptable to consumers in general, but it is meaningful for those who want to watch HDTV. The third receiver requires a rather large industrial antenna until the satellite power increases, and is not practical for home use and is initially suitable for industrial use. For example, if an ultra-high resolution HDTV signal is transmitted and transmitted to various movie theaters by satellite, the movie theater can be digitized by video. In this case, there is also an effect that operating costs of movie theaters and video theaters are reduced.

As described above, when the present invention is applied to TV transmission, there is a great effect that video services of three image quality can be provided in one radio wave frequency band, and that they are compatible with each other. In the embodiment, examples of 4PSK, modified 8QAM, modified 16QAM, and modified 64QAM have been described.
M and 256 QAM can also be realized. Also, the present invention can be applied to a quaternary or octal ASK signal as shown in FIGS. 58 and 68 (a) and (b). Also, 8PSK, 16PS
K, 32PSK can also be implemented. Further, in the embodiment, the example of the satellite transmission has been described, but it goes without saying that the same can be realized by the terrestrial transmission or the wired transmission.

(Embodiment 2) In Embodiment 2, the physical hierarchical structure described in Embodiment 1 is logically further divided by, for example, differentiating the error correction capability, and a logical hierarchical structure is added. In the case of the first embodiment, the respective hierarchical channels have different electric signal levels, that is, different physical demodulation capabilities. On the other hand, the second embodiment differs in logical reproduction capability such as error correction capability. Dividing the data in the hierarchy channel specifically, for example D _1, for example, in two of D _1-1 and D _1-2, error correction capability of one example D _1-1 data of the divided data D
Higher than _1-2 data, than to differentiate the error correction capability, since the error after adjusting capability data D _1-1 and D _{1 -2} in demodulation reproduction are different, lower the C / N value of the transmission signal If the signal level cannot be reproduced by D _1-2 ,
_1-1 means that the original signal can be reproduced within the set error rate. This can be called a logical hierarchical structure.

In other words, by dividing the data of the modulation hierarchical channel and differentiating the magnitude of the inter-code distance for error correction such as the use of an error correction code and a product code, the logical hierarchical structure based on the error correction capability is improved. It is possible to perform additional hierarchical transmission.

[0118] With this, D ₁ channel D _1-1,
Two sub channels D _1-2, D ₂ channel D _2-1, increase to two sub channels D _2-2.

This will be described with reference to FIG. 87 showing the C / N value of the input signal and the hierarchical channel number.
_1-1 can be reproduced with the lowest input signal. This CN value is d
Then, when CN = d, D _1-1 is reproduced, but D _1-2 ,
D _2-1 and D _2-2 are not reproduced. Next, when CN = C or more, _D1-2 is further reproduced. When CN = b, _D2-1 is added, and when CN = a, _D2-2 is added. As described above, as the CN increases, the total number of reproducible hierarchies increases. Conversely, as the CN decreases, the total number of reproducible hierarchies decreases. The transmission distance and the reproducible CN shown in FIG.
This will be described with reference to a value diagram. Generally, as the transmission distance becomes longer as shown by a solid line 861 in FIG. 86, the C / N value of the received signal decreases. The distance from the transmitting antenna at the point where CN = a described in FIG. 85 is La, and when CN = b, Lb, C
Lc when N = C, Ld when CN = d, Le when CN = e
And Sakoi area than the distance from the transmitting antenna Ld only D _1-1 channel, as described in FIG. 85 can be reproduced. Shaded regions 86 a coverage of the D _1-1
Indicated by 2. As is clear from the figure, the _D1-1 channel can be reproduced in the widest area. Similarly, the _D1-2 channel can be reproduced in an area 863 within a distance Lc from the transmitting antenna. Since the area 862 is included in the range within the distance Lc, the D1-1 channel can also be reproduced. Similarly, the area 86
In the area 865, the D _2-1 channel can be reproduced.
_2-2 channel can be played. Thus, C
Hierarchical transmission in which the number of transmission channels that do not accompany the deterioration of the N value gradually decreases can be performed. By separating the data structure into a hierarchical structure and using the multi-level transmission of the present invention, it is possible to achieve a hierarchical transmission in which the data amount gradually decreases as the C / N deteriorates, as in analog transmission. is there.

Next, a specific configuration will be described. Here, an embodiment of two physical layers and two logical layers will be described. FIG. 87 is a block diagram of the transmitter 1. Since this is basically the same as the block diagram of the transmitter of FIG. 2 described in the first embodiment, detailed description is omitted, but the difference is that an error correction code encoder is added. This is abbreviated as ECC encoder. The separation circuit 3 has four outputs of _1-1 , _1-2 , _2-1 and _2-2 , and inputs signals of D1-1, D1-2, D2-1 and D2-2. Separate into two signals and output. Among, D _1-1, D _1-2 signal is first 1EC
The signals are input to the C encoder 871a and sent to the main ECC encoder 872a and the sub ECC encoder 873a, respectively, where they are encoded for error correction.

Here, the main ECC encoder 872a is
It has a stronger error correction capability than the CC encoder 873a. Therefore, as described in the graph of CN- hierarchical channel of FIG. 85, upon demodulation reproduction, D _1-1 channel even at low C / N value than D _1-2 channel D
_1-1 can be reproduced below the reference error rate. D _1-1 is D _1-
It has a logical hierarchical structure that is more resistant to a decrease in C / N than ₂ . Error-corrected D _1-1, D _1-2 signal combiner 874a
Are combined with the D ₁ signal and input to the modulator 4. on the other hand,
The D _2-1 and D _2-2 signals are respectively transmitted to the main encoder 872b and the sub ECC encoder 87 in the second ECC encoder 871b.
3b, and is error-correction-coded by the synthesizer 874b.
_{The two} signals are combined and input by the modulator 4. Main EC
The C encoder 872b has a higher error correction capability than the sub ECC encoder 873b. In this case, the modulator 4 generates a hierarchical modulation signal from the D ₁ signal and the D ₂ signal, and the modulation signal is transmitted from the transmission unit 5. As described above, the transmitter 1 of FIG. 87 has a two-layer physical hierarchical structure of D ₁ and D ₂ by the modulation described in the first embodiment. This description has already been given. Next, _D1-1 and _D1-2 or _D2-1 , D2-1
Each of _2-2 has a logical hierarchical structure of two layers.

Next, the state of receiving this signal will be described.
FIG. 88 is a block diagram of the receiver. The basic configuration of the second receiver 33 that has received the transmission signal of the transmitter of FIG. 87 is substantially the same as that of the second receiver 33 described in FIG. 21 of the first embodiment. The difference is that ECC decoders 876a and 876b are added. In this case, an example of QAM modulation / demodulation is shown. However, the present invention can be applied to an ASK signal such as a quaternary or octal VSB as shown in FIGS. 58 and 68 (a) and (b). Also,
PSK and FSK modulation / demodulation may be used.

In FIG. 88, the received signal is reproduced by the demodulator 35 as D ₁ and D ₂ signals,
a, by 3b, each D _1-1 and D _1-2, D _2-1, 4 of D _2-2
One signal is generated and input to the first ECC decoder 876a and the second ECC decoder 876b. In a 1ECC decoder 876a, D _1-1 signal is mainly ECC decoder 8
The error is corrected by 77a and sent to the combining unit 37. On the other hand, D _1-2 signal is sent to the error-corrected combining unit 37 by sub ECC decoder 878a. Similarly, the second ECC
In the decoder 876b, the D _2-1 signal is used in the main ECC decoder 877b, and the D _2-2 signal is used in the sub ECC decoder 8
The error is corrected at 78b and input to the combining unit 37. The error corrected D _1-1 , D _1-2 , D _2-1 , and D _2-2 signals become one signal in the synthesizing unit 37 and are output from the output unit 36.

In this case, D _1-1 becomes D due to the logical hierarchical structure.
From _1-2, also D _2-1 are as described in FIG. 85 because of high error correction capability than D _2-2, a predetermined error rate can be obtained even at lower state C / N value of the input signal , The original signal can be reproduced.

More specifically, the main ECC decoders 877a and 877b of the High Code Gain and the Low Code
A method of differentiating the error correction capability between the sub ECC decoders 878a and 878b of e Gain will be described. Deputy EC
The ECC decoder of FIG. 165 (b) is added to the C decoder.
In the case of using a standard inter-code distance coding method such as the Reed-Solomon code or the BCH code as shown in the figure, the main ECC decoder uses the product code or the long code of the Reed-Solomon code and the Reed-Solomon code. Method and Fig. 128 (d)
(E) Trellis Decoder 744p, 744 shown in (f)
q, 744r, the error correction capability, namely Cod
e Gain can be differentiated. Thus, a logical hierarchical structure can be realized. Since various methods are known for increasing the inter-code distance, other methods are omitted. The present invention can basically apply any method.

As shown in the block diagrams of FIGS. 160 and 167, an interleaver 744K is provided in the transmission section, and deinterleavers 759K and 936b are provided in the reception section.
According to the Inter leave Table 954 of FIG. 68 (a), by performing interleaving and decoding with the deinterleave RAM 936 × of the deinterleaver 936b, it becomes possible to perform strong transmission against a burst error of the transmission system, and the image is stabilized.

Here, the logical hierarchical structure is represented by C / N in FIG.
This will be described with reference to a relationship diagram between the error rate after error correction. In FIG. 89, a straight line 881 shows the relationship between the C / N of the _D1-1 channel and the error rate, and a straight line 882 shows the D / D
The relationship between the C / N of channel _1-2 and the error rate after correction is shown.

As the C / N value of the input signal decreases, the error rate of the corrected data increases. Below a certain C / N value, the error rate after error correction does not fall below the reference error rate Eth at the time of system design, and the original data is not reproduced normally. Now, C / N can not demodulate the D ₁ channel when: e as gradually indicated when Yuku raising the C / N D _1-1 signal of linear 881 in FIG. 89. Although e ≦ C / N <demodulation when D ₁ channel d may, D _1-1 channel error rate exceeds the Eth, can not be reproduced original data correctly.

When C / N = d, D_1-1Has error correction capability
D_1-2Higher, the error rate after error correction is point 8
85d, it becomes less than Eth, and the data can be reproduced.
Wear. On the other hand, D_1-2Error correction capability is D_1-1Not as high
Error rate after correction is D _1-1Not so low
Error rate after E is E_TwoAnd playback to exceed Eth
I can't. So in this case D_1-1Only can play.

When C / N is improved and C / N = C,
Since the error rate after error correction of D _1-2 reaches Eth, as shown at point 885C, it can be reproduced. This is a point D _2-1, D _2-2, i.e. D ₂ channel demodulation in uncertainty. With the improvement of C / N, D ₂ channel is to reliably demodulated at C / N = b '.

[0131] When the further C / N becomes improved C / N = b, decreased error rate of D _2-1 until Eth as shown in point 885B, D _2-1 will be able to play .
At this time, the error rate of D _2-2 can not be reproduced for greater Eth. C / N = error rate of D _2-2 as shown in the point 885a becomes a is the reduced D _2-2 channel until the Eth becomes possible play.

As described above, by using the error correction capability differentiation, the physical hierarchy D ₁ and D ₂ channels can be further divided into two logical hierarchies and a total of four hierarchies can be transmitted. Can be

In this case, the data structure is changed to a hierarchical structure such that a part of the original signal can be reproduced even if data of a higher hierarchy is lost, and by combining with the multi-level transmission of the present invention, the C / C signal as in analog transmission is obtained. There is an effect that hierarchical transmission in which the data amount gradually decreases with the deterioration of N becomes possible. In particular, image compression technology in recent years is rapidly advancing, so when image compression data is made into a hierarchical structure and combined with hierarchical transmission, video with much higher image quality is transmitted between the same points than analog transmission, and at the same time, analog transmission is performed. As in transmission, it is possible to receive in a wide area while lowering the image quality according to the received signal level in stages. As described above, the effect of hierarchical transmission, which has not been achieved in conventional digital video transmission, can be obtained while maintaining high digital image quality.

The address data of the image segment data, the reference image data at the time of image compression, the descrambling data shown in the rascramble section of FIG. 66, and the data most important for the image expansion of the HDTV signal such as the frame synchronization signal are stored. High Priority Data D
_{As 1-1} , H in FIGS. 88, 133, 170, and 172.
ECC Encorde of high code Gain
r743a, and the high code of the receiver 43 is transmitted.
Received by ECC Decoder 758 of gain. In this method, even if the C / N deteriorates and the error rate of the signal increases, the High Priority Data is used.
Since the error rate of D _1-1 does not increase much, the destruction of the digital video-specific lethal image quality prevented, the effect of Graceful Degradation affect image quality are obtained often. The modulation unit 749 and the demodulation unit 760 in FIGS. 133 and 170 use the above-mentioned 16QAM and 32QAM, and the 4VSB in FIG. 57 and the 8VSB in FIG.
But even 8PSK Graceful Degradat
The effect of ion is obtained.

As shown in FIGS. 133 and 156,
High Priority Data is changed to 2nd da
ECC in ta stream input 744
Encoder 744a and Trellis Encode
er744b performs High code gain error coding, and sets Low Priority data to E
Low code only with CC encoder 743a
By performing error encoding of gain, H
high Priority data and LowPrio
It is possible to make a great difference in the error rate of the data. For this reason, High Priority Data can be received even with a large C / N deterioration in the transmission system, and the C / N is severely deteriorated like a receiver having poor reception conditions such as an automobile TV receiver. Also, with the deterioration of Low Priority Data,
Image quality deteriorates. However, High Priority D
Since the data is reproduced, the arrangement information of the pixel blocks is reproduced, so that an image with reduced resolution and noise can be obtained without destruction of the image, and the viewer can watch the TV program remarkably. The effect is obtained.

(Embodiment 3) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 29 is an overall view of the third embodiment. Embodiment 3 shows an example in which the transmission apparatus of the present invention is used for a digital TV broadcasting system. An input video 402 having an ultra-high resolution is input to an input unit 403 of a first image encoder 401, The data stream is separated into a data stream, a second data stream, and a third data stream, and compressed and output by the compression circuit 405.

The other input images 406, 407, and 408 are compressed and output by the second image encoders 409, 410, and 411 having the same configuration as the first image encoder 401.

[0139] Of these four sets of data, the four sets of signals in the first data string are time-multiplexed by the first multiplexer 413 of the multiplexer 412 according to the TDM method or the like, and are used as the first data string. , To the transmitter 1.

All or a part of the signal group of the second data string is multiplexed by the multiplexer 414 and sent to the transmitter 1 as a second data string. Further, all or a part of the signal group of the third data string is multiplexed by the multiplexer 415,
The data is sent to the transmitter 1 as a data string.

In response to this, the transmitter 1 performs the modulation described in the first embodiment on the three data strings by the modulator 4, and sends it to the satellite 10 by the transmitting unit 5 via the antenna 6 and the transmission path 7 and to the satellite 10 by the repeater 12. , The first receiver 23 and the like.

In the first receiver 23, the signal is received by the small-diameter antenna 22 having the radius r ₁ through the transmission line 21, and only the first data sequence in the received signal is reproduced by the first data sequence reproducing unit 232.
The first image decoder 421 outputs low-resolution video outputs 425 and 4 such as an NTSC signal or a wide NTSC signal.
26 is reproduced and output.

In the second receiver 33, the signal is received by the medium-diameter antenna 32 having a radius of r ₂ ,
The data stream reproducing unit 233 reproduces the first data stream and the second data stream, and the second image decoder 422 reproduces the HDT stream.
A high-resolution video output 427 or a video output 425 or 426 such as a V signal is reproduced and output.

In the third receiver 43, the signal is received by the large-diameter antenna 33 having a radius r ₃ ,
The data stream reproducing unit 233 and the third data stream reproducing unit 234 reproduce the first data stream, the second data stream, and the third data stream, and provide an ultra-high resolution HDTV or the like for a video theater or a movie theater. The video output 428 is output. Video output 4
25, 4266, 427 can also be output. A general digital TV broadcast is broadcast from the digital transmitter 51 and, when received by the first receiver 23, is output as a low-resolution video output 426 such as NTSC.

Next, the configuration will be described in detail based on the block diagram of the first image encoder 401 in FIG. The super high resolution video signal is input to the input unit 403 and sent to the separation circuit 404. The separation circuit 404 separates the signals into four signals by a sub-band coding method. A horizontal low-pass filter 451 and a horizontal high-pass filter 452 such as QMF separate the signal into a horizontal low-frequency component and a horizontal high-frequency component. The components are output by a vertical low-pass filter 455 and a vertical high-pass filter 456, respectively.
_L V _L signal and a horizontal low-vertical high frequency signal is separated into H _L V _H signal for short, the subsampling unit 457 and 458,
The sampling rate is reduced and sent to the compression unit 405.

The horizontal high-frequency component is calculated by the vertical low-pass filter 4.
The 59 and vertical high-pass filter 460, the horizontal high band vertical low frequency signal, for short and _H H V _L signal, the horizontal high band vertical low frequency signal is separated into _H H L _H signal for short, sub-sampling unit 461 , The sampling rate is reduced and sent to the compression unit 405.

[0147] The first performs compression optimal such as DCT in the compression unit 405 in H _L V _L signal of the first compression unit 471 output unit 472
It is output as a first data string.

H_LV_HThe signal is compressed by the second compression unit 473
It is sent to the second output unit 464. H_HV_LThe signal is the third compression
Compressed by 463 and sent to the second output unit 464. H
_HV _HThe signal is separated by a separation circuit 465 into a high-resolution video symbol (H
_HV_H1) and an ultra-high resolution video signal (H_HV_HDivided into 2)
H_HV_H1 is output to the second output unit 464 as H_HV_H2 is 3rd
It is sent to the force unit 468.

Next, the first image decoder 4 will be described with reference to FIG.
21 will be described. The first image decoder 421 receives the output from the first receiver 23 and the first data sequence, that is, D _1, at the input unit 5.
The decompression unit 503 after solving scrambled by de-scrambler 502 and input to 01, the aforementioned H _L V _L signal to change the screen ratio by screen ratio changing circuit 504 and an output section 505 after extension NTSC signal of the image 506, NT
An image 507 of a stripe screen, an image 508 of a full screen of a wide TV, or an image 509 of a side panel screen of a wide TV are output by the SC signal. In this case, two types of scanning lines, non-interlaced or interlaced, can be selected. In the case of NTSC, 525 scanning lines and 1,050 scanning lines by double writing are obtained. In addition, the digital transmitter 5
When a general digital TV broadcast of 4PSK from 1 is received, a TV image can be demodulated and reproduced by the first receiver 23 and the first image decoder 421. Next, the second image decoder will be described with reference to the block diagram of the second image decoder in FIG. First, the D ₁ signal from the second receiver 33 is input from the first input unit 521 and is expanded by the first expansion unit 522.
The sampling rate is doubled by the oversampling unit 523, and H _{L is set} by the vertical low-pass filter 524.
The _VL signal is reproduced. The D ₂ signal is input from the second input unit 530 and separated into three signals by the separation circuit 531.
The second extension part 532, the third extension part 533, and the third extension part 5
34, the sampling rate is doubled by the oversampling units 535, 536, and 537.
38, a vertical low-pass filter 539, and a vertical high-pass filter 540. The _{HL VL} signal and the _HL V _H signal are added by the adder 525, and the
1 and a horizontal low-pass video signal by the horizontal low-pass filter 542, which are sent to the adder 543. H _{H VL} signal and H
_{The H} V _H 1 signal is added by an adder 526, becomes a horizontal high-frequency video signal by an oversampling unit 544 and a horizontal high-pass filter 545, and becomes HDT by an adder 543.
The output unit 546 outputs a high-resolution video signal HD signal such as V, and outputs an image output 547 such as HDTV. In some cases, an NTSC signal is also output.

[0150] Figure 33 is D ₁ signal is a block diagram of a third image decoder D ₂ signal from the first input section 521 HD signal reproduced in the previous step by high-frequency image decoder 527 inputted from the second input unit 530 Is done. D ₃ signal is extended, descrambling, and the synthesized H _H V _H 2 signal is reproduced by the third input from the input unit 551 ultrahigh frequency band image decoder 552. This signal is synthesized with the HD signal by the synthesizer 553 to become an ultra-high resolution TV signal and an S-HD signal, and the output unit 5
An ultra-high resolution video signal 555 is output from 54.

Next, a specific multiplexing method of the multiplexer 401 mentioned in the description of FIG. 29 will be described.

[0152] Figure 34 is a data sequence diagram, the first data stream, D ₁ and the second data string, D ₂ and the third data string D ₃ into six NTSC channel L1, L2, L3, L4, L5,
L6 and six HDTV channels M1 to M6 and six S
-It shows how the HDTV channels H1 to H6 are arranged on the time axis during the period T. Figure 34 is a L1 from L6 to D ₁ signal to the first period T in which to place the time multiplexed by TDM scheme or the like. D ₁ of the domain 6
01 is sent to the H _{L VL} signal of the first channel. Then D is the ₂ signal domain 602 that is difference information M1 between HDTV and NTSC of the first channel in the time domain corresponding to the first channel, the aforementioned H _L V _H signal and _H H V _L signal and _H H V _H
Send one signal. The first is the D ₃ signal domain 603
Super HDTV difference data H1 of the channel, i.e., sends the _H H V _H over 2H1 described in FIG 30.

The case where the TV station of the first channel is selected will be described. First, a general receiver having a small antenna, a first receiver 23 and a first image decoder 421 system can obtain the NTSC or wide NTSC TV signal shown in FIG. Next, a specific receiver having a medium-sized antenna, a second reception transceiver 33 and a second image encoder 422 selects the channel 1 when the first data stream, the domain 60 of D ₁ is selected.
1 and a second data string, HD having the same program content as the NTSC program of the channel 1 signal synthesized and the D ₂ domains 602
Obtain a TV signal.

A large receiver and a third receiver capable of multi-level demodulation
Part of a cinema or the like having the 43 and the third image decoder 423
Is D₁Domain 601 and D_TwoDomain 602
And D _ThreeOf the domain 603 of channel 1
Super-resolution image quality for movie theaters with the same program content as NTSC
Obtain the HDTV signal. Other channels from two to three
It is reproduced in the same way.

FIG. 35 shows the structure of another domain. First, the first channel of NTSC is arranged in L1. Domain of the first time domain of L1 is D ₁ signal 60
In the first part, information S11 including the descrambling information between NTSC and the demodulation information described in the first embodiment is included. Next, the first channel of HDTV is L1 and M
It is divided into ones. M1 is HDTV and NTSC
, And is included in both domain 602 and domain 611 of D ₂ . In this case, 6Mbps NT
When the SC compression signal is adopted and accommodated in L1, the bandwidth of M1 is doubled to 12 Mbps. When L1 and M1 are combined, a band of 18 Mbps can be demodulated and reproduced from the second receiver 33 and the second image decoder 423. On the other hand, using a currently proposed compression method, a HDTV band of about 15 Mbps is used.
A compressed signal can be realized. Therefore, HDTV and NTSC can be simultaneously broadcast on channel 1 in the arrangement shown in FIG. In this case, HDTV cannot be reproduced on channel 2. S21 is HDTV descrambling information. The super HDTV signal is divided into L1, M1, and H1 and broadcast. The difference information of the super HDTV is using the domain 603,612,613 of D _3, 6M an NTSC
When set to bps, a total of 36 Mbps can be sent, and if the compression is increased, a super HDTV signal of about 2,000 scanning lines of movie theater quality can be transmitted.

The arrangement diagram of FIG. 36 shows a case where D ₃ occupies six time domains and transmits a super HDTV signal. When NTSC compressed signal is set to 6Mbps 9
The transmission rate of 54 Mbps can be doubled. Therefore, super HDTV with higher image quality can be transmitted.

The above is the case where one of the horizontal and vertical polarization planes of the radio wave of the transmission signal is used. Here, by using two horizontal and vertical polarization planes, the frequency utilization efficiency is doubled. This will be described below.

[0158] Figure 49 is a horizontal polarization signal D _V1 of the first data stream
And D _V2 and D 2 of the vertical polarization signal D _H1 and the second data string.
_H2, shows a signal arrangement diagram of D _V3 and D _H3 of the third data string. In this case, the vertical polarization signal DV1 of the first data _stream contains a low frequency TV signal such as NTSC, and the horizontal polarization signal _DH1 of the first data stream contains a high frequency TV signal. Therefore, the first receiver 23 having only the vertically polarized antenna has the NTSC
Etc. can be reproduced. On the other hand, the first receiver 23 having the vertical and horizontal polarization antennas is, for example, L ₁
It is possible to obtain the combined HDTV signal M ₁ signal.
That is, when the first receiver 23 is used, NTSC on one side and NTSC and HD on the other side depend on the capability of the antenna.
Since the TV can be reproduced, there is a great effect that the two systems are compatible.

FIG. 50 shows a case where the TDMA system is used. A synchronization section 731 and a card section 741 are provided at the head of each data burst 721. Further, a synchronization information section 720 is provided at the head of the frame. In this case, each time slot group is assigned one channel. For example, in the first time slot 750, NTSC, HDTV, and super HDTV of the same program on the first channel can be transmitted. Each time slot 7
50-750e are completely independent. Therefore, when a specific broadcast station broadcasts in a TDMA system using a specific time slot, there is an effect that NTSC, HDTV, and super HDTV can be broadcast independently of other stations. If the receiving side is also a horizontally polarized antenna and has a first receiver 23, the NTSCTV signal can be converted to an HDTV by using a dual polarized antenna.
Can be played. The second receiver 33 can reproduce a low-resolution super HDTV. With the third receiver 43, the super HDTV signal can be completely reproduced. As described above, a compatible broadcasting system can be constructed. In this case, with the arrangement as shown in FIG. 50, it is possible to perform time multiplexing of continuous signals as shown in FIG. 49 instead of the burst-like TDMA method.
With the signal arrangement shown in FIG. 51, a higher resolution HDTV signal can be reproduced.

As described above, according to the third embodiment, there is a remarkable effect that it is possible to carry out digital TV broadcasting compatible with three signals of an ultra-high resolution type HDTV, HDTV and NTSC-TV. In particular, when transmitted to a movie theater or the like, there is a new effect that images can be digitized.

Here, the modified QAM according to the present invention is
Called AM, a specific error rate will be described.

First, an error rate of 16 SRQAM is calculated. FIG. 99 is a vector diagram of signal points of 16 SRQAM. In the first quadrant, in the case of 16QAM, the intervals between the 16 signal points such as the signal points 83a, 83b, 84a, 85, and 83a are equally spaced, and all are 2δ.

The signal point 83a of 16QAM corresponds to the coordinate axis I.
The axis is at a distance of δ from the Q axis. Here, in the case of 16 SRQAM, if n is defined as a shift value, the signal point 83a shifts and the distance from the coordinate axis is changed to the signal point 8 at the position of nδ.
Move to 3. In this case, n is 0 <n <3. The other signal points 84a, 86a are also shifted to signal points 84, 8
Move to position 6.

When the error rate of the first data string is Pe1,

[0165]

(Equation 1)

When the error rate of the second data string is Pe2

[0167]

(Equation 2)

Is obtained. Next, 36 SRQAM or 32
Calculate the SRQAM error rate. Figure 100 shows 36
It is a signal vector diagram of SRQAM. In the first quadrant, the distance between signal points of 36QAM is defined as 2δ.

The signal point 83a of 36QAM is δ from the coordinate axis.
At a distance. When the signal point 83a reaches 36 SRQAM, the signal point 83a shifts to the position of the signal point 83 and has a distance of nδ from the coordinate axis. Each signal point is shifted to signal points 83, 8
4, 85, 86, 97, 98, 99, 100, 101. A signal point group 90 consisting of nine signal points is regarded as a single signal point, deformation received in 4PSK receiver, the error rate in the case of reproducing the first data column only D ₁ over a Pe1, the signal point group 90 And the error rate when the second data stream D ₂ is reproduced is Pe2.

[0170]

(Equation 3)

Is obtained. In this case, C / N to D in FIG.
The error rate diagram shows the relationship between the error rate Pe and the C / N of the transmission system.
An example of calculating the relationship is shown. Curve 900 is used for comparison.
3 shows an error rate of the conventional 32QAM. Straight line 905
Indicates a straight line having an error rate of 10 to the power of -1.5. Departure
The first case where the shift amount n of the bright SRQAM is 1.5
Tier D ₁Becomes the curve 901a, and the error rate becomes
Rate is 10^-1.5At 32 QAM curve 900
And the C / N value drops by 5 dB₁Is equivalent error level
There is an effect that it can be played back in a format.

[0172] Then n = 1.5 second error rate of the hierarchy D ₂ in the case of the shown by the curve 902a. When the error rate is 10 ^−1.5 , reproduction cannot be performed at the same error rate unless the C / N is increased by 2.5 dB as compared with 32QAM indicated by the curve 900. Curves 901b and 902b have n = 2.
D ₁ and D ₂ in the case of 0 are shown. Curve 902C shows a D _2. To summarize, the error rate is 10 -1.5.
When 22n = 1.5, 2.0, 2.5 in the value of the power,
Compared to 32QAM, D ₁ is improved by 5, 8, and ₁₀ dB, and D ₂ is deteriorated by 2.5 dB.

In the case of 32 SRQAM, when the shift amount n is changed, the first error necessary to obtain a predetermined error rate is obtained.
The C / N values of the data sequence D ₁ and the second data sequence D ₂ are shown in the relationship diagram between the shift amount n and the C / N in FIG. 103. As is clear from FIG. 103, if n is 0.8 or more, a difference in C / N value required for hierarchical transmission, that is, transmission of the first data sequence D ₁ and the second data sequence D ₂ is generated, It can be seen that the effect of the present invention occurs. Therefore, in the case of 32 SRQAM, it is effective under the condition of n> 0.85. The error rate in the case of 16 SRQAM is as shown in the relationship between C / N and error rate in FIG.

In FIG. 102, the curve 900 corresponds to 16QAM.
This shows the error rate of Curves 901a, 901b, 90
1c each first data stream D ₁ of the n = 1.2, 1.5,
It shows the error rate in the case of 1.8. Curve 902a,
902b, 902c each of the second data stream D ₂ n = 1.
The error rates for 2, 1.5 and 1.8 are shown.

The relationship between shift amount n and C / N in FIG. 104 is the first data string D ₁ required to obtain a specific error rate when shift amount n is changed in the case of 16 SRQAM.
If it shows a value of the second data stream D ₂ of the C / N.
As is clear from FIG. 104, in the case of 16 SRQAM, n>
It can be seen that if the ratio is 0.9, the hierarchical transmission of the present invention becomes possible. From the above, if n> 0.9, hierarchical transmission is established.

Here, a specific example in which the SRQAM of the present invention is applied to digital TV terrestrial broadcasting will be described. FIG.
05 shows a relational diagram between the distance between the transmitting antenna and the receiving antenna during terrestrial broadcasting and the signal level. Curve 911 shows the signal level of the receiving antenna when the height of the transmitting antenna is 1250 ft. First, it is assumed that the required error rate of the transmission system required in the digital TV broadcasting system under consideration is 10 −1.5. Region 912
Indicates a noise level, and a point 910 indicates a reception limit point of the conventional 32QAM system at a point where C / N = 15 dB.
Digital HDT at the point of L = 60 miles
V broadcast can be received.

However, the C / N fluctuates temporally in a range of 5 dB due to deterioration of reception conditions such as weather. When the C / N drops in a reception situation where the C / N rank is close to the threshold, the HD
There is a problem that TV reception becomes impossible. In addition, a fluctuation of at least about 10 dB is expected due to the influence of the terrain and the building, and it cannot be received at all points within a radius of 60 miles. In this case, unlike analog, video cannot be transmitted completely in digital. Therefore, the conventional digital T
The service area of the V broadcast system was uncertain.

On the other hand, in the case of 32 SRQAM of the present invention or 8-VSB shown in FIG. 68, as described above, FIG.
With the configuration of FIG. 137, there are three layers. 1st-1st level D
Send an MPEG level low resolution NTSC signal at _1-1 ,
Send resolution TV components in the NTSC or the like at 1-2 hierarchical D ₁ -2, can be in second layer D ₂ sends a high frequency component of HDTV. For example, in FIG. 105, the service area of the first or second layer expands to a 70-mile point as indicated by a point 910a, and the second layer retreats to a 55-mile point as indicated by 910b. The service area diagram of 32 SRQAM in FIG. 106 shows the difference in the area of the service area in this case.
FIG. 106 shows the result of computer simulation, and FIG.
3 is a more specific calculation of the service area diagram. In FIG. 106, regions 708, 703c, 703
a, 703b, 712 are each conventional scheme 32QAM service area of the service area of the 1-1 hierarchies D _1-1, first-
Service area of the two layers D ₁ -2, second service area of the hierarchy D _2, shows the service area of the neighboring analog stations. Among them, the data of the service area of the conventional 32QAM uses the conventionally disclosed data.

In the conventional 32QAM broadcasting method, a service area of nominally 60 miles can be set. But,
In fact, the reception condition was extremely unstable near the reception limit area due to changes in weather and terrain conditions.

However, using 36 SRQAM of the present invention,
The low frequency TV component of MPEG1 grade 1-1 hierarchy D _1-1 sends midrange TV component of NTSC grade 1-2 hierarchy D _1-2, high range HDTV in the second layer D ₂ TV By transmitting the components, the radius of the service area of the high-resolution grade HDTV is reduced by 5 miles as shown in FIG. 106, but the radius of the service area of the medium-resolution grade EDTV is increased by 10 miles or more, and the low-resolution LDTV is reduced. Has the effect of expanding its service area by 18 miles. FIG. 107 shows a shift factor n or s = 1.8.
FIG. 135 shows the service area in FIG. 107 in terms of area.

As a result, first, in the conventional method,
By applying the SRQAM method of the present invention even in an unreceivable area that existed in an area where reception conditions are poor,
At least within the set service area, transmission can be performed so that most receivers can receive TV broadcasts at a medium or low resolution grade. Therefore, the use of the present invention greatly reduces the unreceivable area by using the present invention in the unreceivable area of a building or a low altitude and the area where an adjacent analog station interferes with the ordinary QAM. The number of recipients can be increased.

Secondly, in the conventional digital TV broadcasting system, only a receiver having an expensive HDTV receiver and a receiver can receive a broadcast, so that only a part of the receiver can be viewed in the service area. However, in the present invention, a receiver having a conventional TV receiver of the conventional NTSC, PAL or SECAM system can also increase the digital HDTV broadcast program by NTSC or LDTV grade by adding only a digital receiver. There is an effect that reception becomes possible. Therefore, the receiver can view the program with less economic burden.

At the same time, since the total number of recipients increases, the TV sender side can obtain more viewers, so that a social effect that management as a TV business is more stable is produced.

Third, the area of the receiving area of the middle and low resolution grade is 36% larger than that of the conventional system when n = 2.5. The number of recipients increases with the expansion. Due to the expansion of the service area and the increase in the number of receivers, the business revenue of the TV operator increases accordingly. This is expected to reduce the business risk of digital broadcasting and accelerate the spread of digital TV broadcasting.

As shown in the service area diagram of 32 SRQAM in FIG. 107, the same effect can be obtained when n or s = 1.8. By changing the shift value n, each broadcasting station can be connected to the HDTV receiver and the NTSCTV.
Depending on local conditions and circumstances, such as receiver distribution,
Change the service area 70 of the D ₁ and D ₂ of the SRQAM
By setting 3a and 703b to optimal conditions, the receiver can obtain the maximum satisfaction and the broadcasting station can obtain the maximum number of receivers.

In this case, when n> 1.0, the above effects can be obtained. Therefore, 32SR
In the case of QAM, n is 1 <n <5. Similarly, in the case of 16 SRQAM, n becomes 1 <n <3.

In this case, in the SRQAM system for obtaining the first and second layers by shifting as shown in FIGS. 99 and 100,
If n is 1.0 or more in 16 SRQAM, 32 SRQAM, and 64 SRQAM, the effect of the present invention can be obtained in terrestrial broadcasting.

In the embodiment, the case where the video signal is transmitted has been described. However, the audio signal is divided into a high-frequency part or a high-resolution part and a low-frequency part or a low-resolution part.
When transmitted using the transmission method of the present invention as a data string,
Similar effects can be obtained.

When used for PCM broadcasting, radio, and mobile phones, there is an effect that the service area is expanded.

In the third embodiment, as shown in FIG. 133, a sub-channel based on TDM is provided in combination with a time division multiplexing (TDM) system, and an ECC encoder 74 is provided.
3a and 2 as shown in ECC Encoder 743b.
By differentiating the error correction code gain of one sub-channel, the threshold of each sub-channel can be differentiated to increase the number of multi-level transmission sub-channels. In this case, as shown in FIG.
Code gain of ECC encoder such as Trellis Encoder of 2 subchannels of VSB-ASK signal of 6VSB
You may change s. The detailed description is the same as the description of FIG.

FIG. 131 is a block diagram of a magnetic recording / reproducing apparatus, and FIG. 137 is a block diagram of a transmission apparatus. Up converter of the transmitter of the transmission device; Down of the receiver
By replacing the converters with the magnetic head recording signal amplification circuit and the magnetic head reproduction signal amplification circuit of the magnetic recording / reproducing apparatus, both have completely the same configuration. Therefore, the configuration and operation of the modem are exactly the same. Similarly, it can be seen that the magnetic recording / reproducing system of FIG. 84 has the same configuration as the transmission system of FIG. 156.
If the configuration is to be simplified, the configuration shown in FIG. 157 can be used. If the configuration is to be further simplified, the configuration shown in FIG. 158 can be used.

In the simulation shown in FIG.
1-1 shows a case where with a difference of 5dB Coding Gain between subchannels D _1-1 and a second 1-2 subchannel D _1-2. SRQAM is called “C-CDM” and is a signal point code division multiplexing method (Constellation-Code Division) of the present invention.
Multiplex) is applied to rectangle-QAM. C
-CDM is a multiplexing method independent of TDM and FDM. This is a method of obtaining a sub-channel by dividing a signal point code corresponding to a code. By increasing the number of signal points, expandability of transmission capacity not available in TDM or FDM can be obtained. This is achieved while maintaining almost complete compatibility with conventional equipment. Thus, C-CDM has an excellent effect.

Although the embodiment in which the C-CDM and the TDM are combined is used, the same effect of relaxing the threshold can be obtained by combining the embodiment with the frequency division multiplexing (FDM). For example, when used for TV broadcasting, the frequency distribution of a TV signal shown in FIG. 108 is obtained. Conventional analog broadcasting, for example, a signal of the NTSC system has a frequency distribution like a spectrum 725. The biggest signal is video carrier 7
22. The color carrier 723 and the audio carrier 724 are not so large. In order to avoid mutual interference, there is a method of dividing a digital broadcast signal into two frequencies by FDM. In this case, the first carrier 726 and the second carrier 726 are arranged so as to avoid the image carrier 722 as shown in FIG.
By dividing the signal into carriers 727 and sending the first signal 720 and the second signal 721, interference can be reduced. First signal 7
By transmitting a low-resolution TV signal with a large output by 20 and a high-resolution signal by a small output with the second signal 721, hierarchical broadcasting by FDM is realized while avoiding interference.

FIG. 134 shows a case where the conventional system 32QAM is used. Since the output of the sub-channel A is larger, the threshold value Threshold1 may be smaller by 4 to 5 dB than the threshold value Theshold2 of the sub-channel B. Therefore, a two-layer hierarchical broadcast having a difference of 4 to 5 dB threshold is realized. However, in this case, the level of the received signal is
Below this, all of the hatched signals of the second signal 721a occupying a large amount of information cannot be received at all, and only the first signal 720a having a small amount of information cannot be received.
In the hierarchy, only images with extremely poor image quality can be received.

However, when the present invention is used, first, as shown in FIG. 108, a subchannel 1ofA is added to the first signal 720 using 32 SRQAM obtained by C-CDM. A lower resolution component is added to the sub-channel 1ofA having a lower threshold. 32S of the second signal 721
RQAM is set, and the threshold value of the sub-channel 1ofB is adjusted to the threshold value Thershold2 of the first signal. Then the signal level becomes Th
Even if it drops to reshold-2, it will not be possible to receive. The area is only the second signal portion 721a indicated by oblique lines, and the transmission amount does not decrease so much because the sub-channel 1ofB and the sub-channel A can be received. Therefore, there is an effect that an image with good image quality can be received even at the signal level of Th-2 in the second hierarchy.

By transmitting the normal resolution component to one of the sub-channels, the number of hierarchies is further increased, and the effect that the service area of low resolution is expanded. Audio information or synchronization information is assigned to the sub-channel having the lower threshold value.
By inserting important information such as the header of each data, this important information can be reliably received, so that stable reception is possible. When a similar technique is used for the second signal 721, the number of service area layers increases. When the scanning lines of HDTV are 1050 lines, in addition to 525 lines, C-CDM
This adds 775 service areas.

As described above, when the FDM and the C-CDM are combined, an effect that the service area is expanded is produced. In this case, two sub-channels are provided by FDM, but the frequency may be divided into three and three sub-channels may be provided.

Next, a method of avoiding interference by combining TDM and C-CDM will be described. As shown in FIG. 109, the analog TV signal includes a horizontal retrace unit 732 and a video signal unit 731. The fact that the signal level of the horizontal retrace unit 732 is low and that the signal is not output to the screen during this period is used. By synchronizing the digital TV signal with the analog TV signal, it is possible to send important data, for example, a synchronization signal or the like to the horizontal retrace synchronization slots 733 and 733a during the horizontal retrace section 732, or to transmit a lot of data at a high output. it can.
This has the effect that the amount of data can be increased or the output can be increased without increasing interference. Similar effects can be obtained by providing the vertical retrace synchronization slots 737 and 737a in synchronization with the periods of the vertical retrace units 735 and 735a.

FIG. 110 is a diagram showing the principle of C-CDM.
FIG. 111 shows a code allocation diagram of the 16-QAM extended version C-CDM, and FIG. 112 shows a code allocation diagram of the 32QAM extended version. As shown in FIGS. 110 and 111, 256QAM is the first, second, third and fourth layers 740a and 740.
b, 740c, and 740d, each having 4, 16, 64, and 256 segments. 256QAM signal point codeword 742d of fourth layer 740d
Is 8-bit "11111111". This is 2b
four codewords 741a, 741b, 74
1c, 741d, and the first, second, third, and fourth layers 740
a, 740b, 740c, 740d signal point area 742
a, 742b, 742c, 742d each have "11",
“11”, “11”, and “11” are assigned. Thus,
There are sub-channels of 2 bits, that is, sub-channel 1, sub-channel 2, sub-channel 3, and sub-channel 4. This is called signal point code division multiplexing. FIG. 111 shows a specific code arrangement of an extended version of 16QAM, and FIG. 112 shows an extended version of 36QAM. CC
The DM multiplexing scheme is independent. Therefore, conventional frequency division multiplexing (FDM) and time division multiplexing (TD)
By combining with M), there is an effect that the number of sub-channels can be further increased. Thus, a new multiplexing system can be realized by the C-CDM system. Although C-CDM has been described using Rectangle-QAM, other modulation schemes having signal points, for example, other forms of QAM, PSK, ASK, and the frequency domain can be regarded as signal points, and FSK can be multiplexed similarly.

For example, the error rate of subchannel 1 of the above-mentioned 8PS-APSK is

[0201]

(Equation 4)

The Pe _{2-8 of the} sub-channel 2 is

[0203]

(Equation 5)

The error rate of sub-channel 1 of 16-PS-APSK (PS type) is

[0205]

(Equation 6)

The error rate of sub-channel 2 is

[0207]

(Equation 7)

The error rate of sub-channel 3 is

[0209]

(Equation 8)

[0210] (Embodiment 4) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 37 is an overall system diagram of the fourth embodiment. The fourth embodiment uses the transmission device described in the third embodiment for terrestrial broadcasting, and has almost the same configuration and operation. Example 3
The only difference between FIG. 29 and FIG. 29 is that the transmitting antenna 6a is a terrestrial transmission antenna and that each antenna 21a, 31a, 41a of each receiver is a terrestrial transmission antenna. is there. The other operations are exactly the same, and a repeated explanation will be omitted. Unlike satellite broadcasting, in the case of terrestrial broadcasting, the distance between the transmitting antenna 6a and the receiver is important. A distant receiver receives weaker radio waves, and cannot demodulate a signal simply multi-level QAM-modulated by a conventional transmitter and cannot watch a program.

However, when the transmission apparatus of the present invention is used, the first receiver 23 having the antenna 22a at a long distance as shown in FIG.
The modulated signal is received, demodulated in the 4PSK mode, and the D1 signal of the first data string is reproduced, so that an NTSC TV signal is obtained. Therefore, even if the radio wave is weak, a TV program can be viewed at a medium resolution.

Next, in the second receiver 33 in which the antenna 32a is located at a middle distance, since the arriving radio wave is sufficiently strong, the deformation 16 or 6
The second data string and the first data string can be demodulated from the 4QAM signal, and an HDTV signal can be obtained. Therefore, the same TV program is HD
You can watch on TV.

On the other hand, the third receiver 43, which is located at a short distance or has an antenna 42a of ultra-high sensitivity, has the first, second, and third data strings D1, D2 because the radio waves have sufficient strength to demodulate the modified 64QAM signal. , D3 to obtain an ultra-high resolution HDTV signal. You can watch the same TV program on a super HDTV with the same image quality as a large movie.

The method of arranging frequencies in this case can be explained by replacing the time multiplexing arrangement with the frequency arrangement with reference to FIGS. 34, 35 and 36. As shown in FIG. 34, when frequencies are assigned to channels 1 to 6 D
In one signal, L1 of NTSC is used as the first channel, and the difference information of HDTV is used in M1 of the first channel of the signal D2.
By locating the difference information of the ultra high resolution HDTV in H1 of the first channel of the signal, it is possible to transmit NTSC, HDTV and super resolution HDTV on the same channel. Also, as shown in FIG. 35 and FIG.
If the use of the signal or the D3 signal is permitted, higher-quality HDTV and ultra-high-resolution HDTV can be broadcast.

As described above, there is an effect that three digital TV terrestrial broadcasts compatible with each other can be broadcast using the D2 and D3 signal areas of one channel or another channel. In the case of the present invention, there is an effect that a TV program of the same content on the same channel can be received in a wider area if the resolution is medium.

As digital terrestrial broadcasting, HDTV broadcasting in a 6 MHz band using 16QAM has been proposed.
However, since these systems are not compatible with NTSC, it is premised that a simulcast system in which the same program is transmitted through another NTSC channel is used. Also 16QAM
In the case of, the service area that can be transmitted is expected to be narrow. The use of the present invention for terrestrial broadcasting not only eliminates the need to provide a separate channel, but also has the effect that a broadcast service area is wide because a program can be viewed at a medium resolution even with a distant receiver.

FIG. 52 shows a conventional proposed HDT.
FIG. 5 is a diagram showing a reception interference area diagram for V digital terrestrial broadcasting, in which an HDTV digital broadcasting station 701 using a conventionally proposed system can receive an HDTV from a receivable area 702 and an adjacent analog broadcasting station 711 can receive. An area 712 is shown. In the overlapping portion 713 where the two overlap, it is impossible to stably receive at least HDTV due to radio wave interference of the analog broadcasting station 711.

Next, FIG. 53 is a diagram showing a reception disturbance area when the hierarchical broadcasting system according to the present invention is used. In the present invention, when the transmission power is the same as that of the conventional system, the high-resolution receivable area 703 of the HDTV is slightly narrower than the receivable area 702 of the above-described conventional method because the power use efficiency is low. However, there is a low-resolution receivable area 704 such as digital NTSC which is wider than the receivable area 702 of the conventional system. It consists of the above two areas. In this case, the radio wave interference from the digital broadcasting station 701 to the analog broadcasting station 711 is at the same level as the conventional system shown in FIG.

In this case, in the present invention, the analog broadcasting station 71
There are three areas of interference from one to the digital broadcast station 701. One is a first interference area 705 that cannot receive HDTV or NTSC. The second is disturbed but N
Second jamming area 706 that can receive TSC as before jamming
Is indicated by a single oblique line. Here, the NTSC uses the first data string that can be received even if the C / N is low, so that the influence range of the interference is narrow even if the C / N decreases due to the radio wave interference of the analog station 711.

The third is a third interference area 707 in which HDTV can be received before the interference, but only NTSC can be received after the interference.
Is indicated by double oblique lines.

As described above, H before interference is lower than in the conventional method.
The receiving area of the DTV is slightly narrower, but the receiving range including the NTSC is wider. Further, even in an area where HDTV could not be received by the conventional system due to the interference from the analog broadcasting station 711, the same program as that of the HDTV was transmitted to the NT.
Reception is possible at the SC. Thus, there is an effect that the unreceivable area of the program is greatly reduced. In this case, by slightly increasing the transmission power of the broadcasting station, the receivable area of the HDTV becomes equivalent to the conventional system. Furthermore, programs can be received with NTSCTV quality in distant areas where no programs could be viewed in the conventional system, or in areas where analog stations overlap.

Although the example using the two-layer transmission system has been described, a three-layer transmission system may be used as shown in the time allocation diagram of FIG. By separating HDTV into three levels of images of HDTV, NTSC, and low-resolution NTSC and transmitting them, the receivable area in FIG. 53 expands from two layers to three layers, and the outermost layer becomes a wide area. In the first obstruction area 705, which cannot be received at all, a program can be received with the quality of the low-resolution NTSCTV. The above is an example in which a digital broadcasting station interferes with analog broadcasting.

Next, an embodiment will be described under the condition that digital broadcasting does not interfere with analog broadcasting.
In the system using an empty channel which is currently being studied in the United States and the like, the same channel is used adjacently. For this reason, digital broadcasting that is to be broadcast later must not interfere with existing analog broadcasting. Therefore, it is necessary to lower the transmission level of the digital broadcast as compared with the case where the transmission is performed under the conditions shown in FIG. In this case, in the case of the conventional 16QAM or 4ASK modulation, the receivable area 708 of the HDTV becomes very small because the non-receivable area 713 indicated by double oblique lines is large as shown in the interference state diagram of FIG. . The service area is narrowed, and the number of recipients is reduced correspondingly, so the number of sponsors is reduced. Therefore, it is expected that the broadcasting business is hardly economically established in the conventional system.

Next, FIG. 55 shows a case where the broadcast system of the present invention is used. The HDTV high resolution receivable area 703 is
It is slightly smaller than the receivable area 708 of the conventional method. However, a lower resolution receivable area 704 such as NTSC is obtained in a wider range than the conventional method. The part indicated by a single diagonal line cannot receive the same program at the HDTV level, but the NTSC
Indicates the area that can be received at the level. Among them, the first interference area 705 receives interference from the analog broadcasting station 711, and neither HDTV nor NTSC can be received.

As described above, in the case of the same radio wave intensity, in the hierarchical broadcasting according to the present invention, the area where the HDTV quality can be received is slightly narrowed, but the area where the same program can be received with the NTSCTV quality increases. This has the effect of increasing the service area of the broadcasting station. The effect is that the program can be provided to more recipients. The broadcasting business of HDTV / NTSCTV can be established more economically and stably.
When the ratio of digital broadcasting receivers increases in the future, the interference rules for analog broadcasting are relaxed, so that the radio wave intensity can be increased. At this point, the service area of the HDTV can be enlarged. In this case, by adjusting the interval between the signal points of the first data string and the second data string, FIG.
The digital HDTVINTSC receivable area and the digital NTSC receivable area indicated by 5 can be adjusted. In this case, by transmitting information of this interval to the first data string as described above, reception can be performed more stably.

FIG. 56 is a diagram showing the state of interference when switching to digital broadcasting in the future. In this case, unlike FIG. 52, the adjacent station is a digital broadcasting station 701a that performs digital broadcasting. Since the transmission power can be increased, the high-resolution receivable area 703 such as HDTV can be expanded to a receivable area 702 equivalent to analog TV broadcasting.

The conflict area 71 between the two receivable areas
In No. 4, the program cannot be reproduced in the HDTV quality with a normal directional antenna because of mutual interference.
It can be received with the quality of TSCTV. When an antenna with a very high directivity is used, a program of a broadcasting station in the directivity direction of the antenna can be received with HDTV quality. The low-resolution receivable area 704 is wider than the standard receivable area 702 of analog TV broadcasting, and the competing areas 715 and 716 of the low-resolution receivable area 704a of an adjacent broadcast station are broadcast stations in the direction of the antenna directivity. Is NTSCTV
You can play with the quality of.

By the way, the regulation conditions will be further relaxed at the time of full-scale popularization of digital broadcasting in the future, and the HDTV of a wide service area will be provided by the hierarchical multi-value broadcasting of the present invention.
Broadcasting becomes possible. Even at this point, by adopting the hierarchical multi-valued broadcasting system of the present invention, a HDTV reception range as wide as that of the conventional system can be ensured, and distant regions and competitive regions that cannot be received by the conventional system. In this case, since the program can be received with NTSCTV quality, there is an effect that the defective portion of the service area is greatly reduced.

(Embodiment 5) Embodiment 5 is an embodiment in which the present invention is applied to amplitude modulation, that is, the ASK method. FIG. 57 is a diagram showing the arrangement of quaternary VSB-ASK signal signal points in Embodiment 5. , Four signal points 721, 722, 723, 724. FIG. 68 (a) shows the constellation of an 8-level VSB signal.
lation. In case of 4-value, 2-bit data, 8
In the case of a value, 4-bit data can be sent in one cycle. In the case of 4VSB, signal points 721, 722, 723,
724 can correspond to, for example, 00, 01, 10, and 11.

In order to perform multi-level transmission according to the present invention, as shown in the signal point arrangement diagram of 4-level ASK such as 4-level VSB in FIG. Treat the signal points 723 and 724 as another group, the second signal point group 7
26. Then, the interval between the two signal point groups is made wider than the interval between the equally spaced signal points. That is, the signal point 72
Spacing apart of the signal points 723 and 724 when the L of 1,722 good at the same L but distance L _o of the signal point 722 and signal points 723 is set larger than L.

[0232] To set that is the L _o> L. This is a characteristic of the hierarchical multi-level transmission system of the present invention. However it may become temporarily or permanently L = L _o by the conditions and settings, depending on the design of the system. In the case of an 8-level VSB, Constella as shown in FIGS.
ti on.

As shown in FIG. 59A, _one bit data of the first data string D1 can be made to correspond to two signal point groups. For example, the first signal point group 725 is set to 0, the second
If the signal point group 726 of the first data string is defined as 1,
Bit signals can be defined. Next, 1 of the second data string D ₂
A bit signal is made to correspond to two signal point groups in each signal group. For example, as shown in FIG.
If 23 is set to D ₂ = 0 and the signal points 722 and 724 are set to D ₂ = 1, the data of the second data string D ₂ can be defined. Also in this case, it is 2 bits / symbol.

By arranging signal points in this way,
The multi-level transmission of the present invention can be performed by the ASK method. When the signal-to-noise ratio, that is, the C / N value, is sufficiently high, the hierarchical multilevel transmission system is no different from the conventional equally spaced signal point system. However, if the C / N value is low, the second data stream D ₂ by using the even present invention in exactly the condition can not play data in the conventional manner but can not be reproduced, the first data stream D ₁ can be reproduced. Explaining this, the state in which the C / N is deteriorated can be shown as a signal point arrangement diagram of 4VSB-ASK in FIG. That is, the signal points reproduced by the receiver are dispersed signal point regions 721a 722a,
23a and 724a are distributed in a Gaussian distribution over a wide range. In such a case, discrimination between the signal point 721 and the signal point 722 based on the slice level 2 by the quaternary slicer,
It becomes difficult to distinguish signal point 723 and signal point 724 based on slice level 4. That second error rate of the data stream D ₂ is very high. However, as is apparent from the figure, the groups of the signal points 721 and 722 and the signal points 723 and 72
It is easy to distinguish from the group No. 4. That is, the first signal point group 725 and the second signal point group 726 can be distinguished.
Therefore, the first data stream D ₁ will be playable on a low error rate.

Thus, data strings D ₁ and D _{2 of} two layers can be transmitted and received. Thus both in good condition and the region of C / N of the transmission system of the first data stream D ₁ and the second column D ₂ is C /
The bad and regions with N there is an effect that it is multi-valued transmission only the first data stream D ₁ can be reproduced.

FIG. 61 is a block diagram of the transmitter 741. The input section 742 includes a first data string input section 743 and a second data string input section 744. The carrier from the carrier generator 64 is amplitude-modulated in the multiplier 746 by an input signal obtained by combining the signal from the input unit 742 in the processing unit 745,
A quaternary or octal ASK signal as shown in FIG. The 4ASK or 8ASK signal is further band-limited by a band-pass filter 747, and FIG.
Side Ba with Carrier remaining a little like
Vestigial Side Band with nd, that is, A of VSB signal
The SK signal is output from the output unit 748.

Here, the output waveform after passing through the filter will be described. FIG. 62A is a frequency distribution diagram of the ASK modulation signal. As shown, there are sidebands on both sides of the carrier. This signal is used to remove one sideband while leaving a small carrier component like a transmission signal 749 in the band-pass filter (FIG. 62B) of the filter 747. This is called VSB signal, but when the f ₀ and modulation frequency band, since that can be transmitted in a frequency band of about f _0/2, it is known that spectrum efficiency is good. The ASK signal shown in FIG. 60 is originally 2 bits / symbol, but when the VSB method is used, 4VSB and 8VSS are used.
B is 4bi of 16QAM and 32QAM in the same frequency band
An information amount corresponding to 5 bits / symbol of t / symbol can be transmitted.

Next, in the VSB receiver 751 shown in the block diagram of FIG. 63, the signal received by the terrestrial antenna 32a passes through the input section 752, and is mixed in the mixer 753 with the signal from the variable oscillator 754 variable by channel selection. And converted to a lower intermediate frequency. Next, the signal is detected by a detector 755, and becomes a baseband signal by an LPF 756. In the case of 4VSB, a 4-level slicer,
In the case of 8VSB, the first data sequence D ₁ and the second data sequence D ₂ are reproduced by the discriminating / reproducing device 757 having an 8-level slicer, and are output from the first data sequence output unit 758 and the second data sequence output unit 759.

Next, a case where a TV signal is transmitted using the transmitter and the receiver will be described. FIG. 64 shows a video signal transmitter 774.
It is a block diagram of. High resolution TV signal such as HDTV signal is input to the input unit 403 of the first image encoder 401, a separating circuit 404 of the video such as sub-band _{filter, H L V L, H L} V H, H H V L, H It is separated into high-frequency TV signal and a low TV signal such as _H H _H. Since this content has been described in the third embodiment with reference to FIG. 30, detailed description will be omitted. The separated TV signal is encoded in the compression section 405 using a technique such as DPCMDCT variable length encoding used in MPEG or the like. The motion compensation is processed in the input unit 403. The four compressed image data are combined by a combiner 771 into two data, a first data string D ₁ and a second data string D ₂ .
Data strings. In this case, the _{HL VL} signal, that is, the low-frequency image signal is included in the first data string. First data string input section 743 and second data string input section 744 of transmitter 741
And is subjected to amplitude modulation to become an ASK signal such as VSB, which is broadcast from a ground antenna.

FIG. 65 is a block diagram of the entire TV receiver for digital TV broadcasting. The broadcast signal received by the terrestrial antenna 32a is input to the input unit 752 of the receiver 751 in the TV receiver 781, and the signal of an arbitrary channel desired by the receiver is selected and demodulated by the detection and demodulation unit 760. The first data string D ₁ and the second data string D ₂ are reproduced and the first
Output from the data string output unit 758 and the second data string output unit 759. Detailed explanations are omitted because they overlap. The D ₁ and D ₂ signals are input to the separation unit 776. The D ₁ signal is supplied to the separator 77
7, the H _L V _L compressed component is input to the first input unit 521. The other is combined with the D ₂ signal by the combiner 778 and input to the second input unit 531. The H _L V _L compressed signal input to the first input unit 521 in the second image decoder is
Sent to H _L V _L signal is expanded image combining unit 548 and the screen ratio changing circuit 779 by first extending portion 523. Original T
If V signal is an HDTV signal, H _L V _L signal is wide N
If the original signal is an NTSC signal, M
Low resolution TV lower in quality than NTSC such as PEG1
Signal.

[0241] In order to have set the original video signal HDTV signal and in this description, T of H _L V _L signal is wide NTSC
V signal. If the screen aspect ratio of the TV is 16: 9, it is output as the video output 426 via the output unit 780 with the screen ratio of 16: 9. If the screen aspect ratio of the TV is 4: 3, the screen aspect ratio changing circuit 779 changes the screen aspect ratio from 16: 9 to 4: 3 in the letterbox format or the side panel format, and outputs it via the output unit 780. Output as a video output 425.

On the other hand, the second data string D ₂ from the second data string output section 759 is combined with the signal of the separator 777 in the combiner 778 of the separation section 776, and the combined signal is supplied to the second input section 531 of the second image decoder. Input, and H
_{L V H, H H V L} , H H V H are separated into compressed signals of each second
Decompression unit 535, the third extension portion 536, is sent to the fourth extension portion is extended original _{H L V H, H H V} L, the _H H V _H signal. The H _L V _L signal is applied to these signals, the image synthesizing unit 54
8 and synthesized into one HDTV signal, output from the output unit 546, and output via the output unit 780.
It is output as a V video signal 427.

This output section 780 is the second data string output section 7
The error rate detection unit 782 detects the error rate of the 59 second data string.
In detecting, or if an error rate is high continues for a predetermined time to output the low resolution video signal for a certain time automatically H _L V _L signal, or to stop the video output, or to operate the filter, Issue system control commands such as restoring synchronization.

As described above, transmission and reception of a hierarchical broadcast can be performed. If the transmission conditions are good, for example, for a broadcast with a TV transmission antenna close to the broadcast, both the first data sequence and the second data sequence can be reproduced, so that the program can be received with HDTV quality. The relative distance is long broadcast transmitting antenna, and reproducing the first data stream, and outputs a low resolution TV signal from the V _L H _L signal. This allows HD
There is an effect that the same program can be received in a wider area with the quality of TV or the quality of NTSCTV.

If the function of the receiver 751 is reduced only to the first data string output unit 768 as shown in the block diagram of the TV receiver in FIG. 66, the receiver does not need to handle the second data string and the HDTV signal. The configuration can be greatly simplified. The image decoder may use the first image decoder 421 described in FIG. In this case, NTSCTV
Is obtained. Although the program cannot be received at the HDTV quality, the cost of the receiver is greatly reduced. Therefore, it may be widely spread. In this system, the conventional T
By adding many receiving systems with V-displays as adapters without modification, digital TV
There is an effect that a broadcast can be received.

When a scrambled 4VSB or 8VSB signal is received as shown in FIG.
B, the descrambling signal transmitted by the 8VSB signal and the number of the descrambling number memory 502c in the descrambler 502 are collated by the descrambling number collator 502b.
By canceling the scramble, the scramble of the specific scramble program can be properly canceled.

With the configuration as shown in FIG. 67, a receiver having the functions of a satellite broadcast receiver for demodulating a PSK signal and a terrestrial broadcast receiver for demodulating a VSB signal can be easily configured. In this case, the PSK signal received from the satellite antenna 32 is mixed with the signal from the oscillator 787 in the mixer 786,
The signal is converted into a low frequency signal, and is input to the input unit 34 of the TV receiver 781, and is input to the mixer 753 described with reference to FIG. Data streams D ₁ and D _{2 of} the PSK or QAM signal converted to a lower frequency of a specific channel of the satellite TV broadcast are demodulated by the demodulation unit 35, and the image signal is transmitted by the second image encoder 422 via the separation unit 788. And output from the output unit 780. On the other hand, digital terrestrial broadcasting and analog broadcasting received by the terrestrial antenna 32a are input to the input unit 752, and a specific channel is selected by the mixer 753 in the same process as described with reference to FIG. It becomes a baseband signal of only the band. The signal enters the mixer 753 for analog satellite TV broadcasting and is demodulated. In the case of digital broadcasting, the data streams D ₁ and D ₂ are reproduced by the discriminator / reproducer 757 and the second image decoder 42
2 reproduces and outputs a video signal. When receiving terrestrial and satellite analog TV broadcasts, the video demodulator 7
The analog TV signal demodulated by 88 is output to the output unit 7.
80 is output. With the configuration of FIG.
3 can be shared by satellite broadcasting and terrestrial broadcasting. Also, the second image decoder 422 can be shared. In digital terrestrial broadcasting, A
When the SK signal is used, a detector 755 and a receiving circuit such as an LPF 756, which are the same as those used in conventional analog broadcasting, can be used for AM demodulation. As described above, the configuration shown in FIG. 67 has an effect that the receiving circuit is widely used and the number of circuits is reduced.

Further, in this embodiment, the quaternary ASK signal is divided into two groups, and multi-level transmission of each one bit of two layers D ₁ and D ₂ is performed. However, the 8VSB shown in FIGS.
8-valued A shown in the signal Constellation diagram
When the SK signal, that is, 8 level-VSB is used, D ₁ ,
A total of 3 bits / symb of 1 bit for each of the three layers D ₂ and D ₃
ol can be transmitted in multiple levels. As shown in FIG. 68 (a), the first describing the assigning a 1bit th code, D ₃ signal signal point of the signal point 721a and 721b, 7
22a and 722b, 723a and 723b, 724a and 7
24b, that is, 1 bit. Next, the next 1 bit
The signal point of D ₂ is a signal point group 721
And 722, and one bit of the binary of the signal point groups 723 and 724
It is. 2 D ₃ data with large signal point groups 725 726
This is 1 bit of the value. In this case, the four signal points 721, 722, 723, and 724 in FIG.
21a and 721b, 722a and 722b, 723a and 7
23b, 724a and 724b, and by separating the groups, the multi-level transmission of three layers at maximum is possible. It is also possible to L = L ₀ as described above.

The transmission of digital HDTV images of three layers or the like using this three-layer multi-value transmission system is not described in the third embodiment.
And detailed description of the operation is omitted here.

Here, the TV based on the 8-valued VSB shown in FIG.
The effect of broadcasting will be described. While 8VSB has a large amount of transmission information, the error rate for the same C / N value is higher than 4VSB. However, when high-definition HDTV broadcasting is performed, there is an effect that the error rate can be reduced and hierarchical TV broadcasting can be performed in the future because a large amount of error correction code is input due to the extra transmission capacity.

Here, the effects of 4VSB, 8VSB and 16VSB will be described in comparison. In the case of terrestrial broadcasting using the frequency band of NTSC or PAL, as shown in FIG.
A substantial transmission band of MHz is allowed. In the case of 4VSB, since the frequency utilization efficiency is 4 bit / Hz, there is a data transmission capacity of substantially 5 MHz × 4 = 20 Mbps. On the other hand, transmission of a digital HDTV signal requires at least 15 Mbps to 18 Mbps. Therefore, 4
Since the data capacity of −VSB has no margin, as shown in the comparison diagram of FIG.
Only 10 to 20% of the actual transmission amount of TV can be taken.

Next, in the case of 8-VSB, since the frequency utilization efficiency is 6 bits / HZ, 5 MHz × 6 = 30 Mbps
Is obtained. As described above, transmission of the HDTV signal requires 15 to 18 MHz.
In the case of the modulation method, as shown in FIG. 169, an information amount of 50% or more of the substantial transmission amount of the HDTV signal can be used for the error correction code. Therefore, HDT of the same data rate
Under the condition that the V digital signal is terrestrial broadcast in a 6 MHz band, the 8VSB can add a larger capacity error correction code. Therefore, as shown in the error rate curves 805 and 806 in FIG. For the same C / N value of T, T
The error rate of the CM-8VSB after error correction is lower than that of 4VSB, which has a low error correction code gain. Therefore, there is an effect that the service area in TV terrestrial broadcasting is wider in 8VSB error-coded by High code gain than in 4VSB.
Indeed, the 8VSB has a disadvantage that the receiver circuit becomes more complicated due to an increase in the number of error correction circuits. But VSB
Since the ASK method is a amplitude modulation method, Q
Originally, the equalization of the receiver compared to the AM modulation method
The circuit scale of r is very small. Therefore, even if an error correction circuit is added, the overall circuit scale is 32 V in the 8VSB system.
It does not increase compared to the QAM method. Therefore, 8VSB
According to the method, an appropriate digital HDTV receiver having a wide service area and an overall circuit scale is realized.

A specific example of the error correction method will be described later in Example 5 and the like. However, the transmitter / receiver block shown in FIG. 84, FIG. 131, FIG. 137, FIG. 156, and FIG. ECC744a and Trellis Enc
Using the order 744b, the 4VSB described in FIG.
The data is transmitted using the 8VSB and 16VSB VSB modulation section 749. On the receiver side, using the VSB demodulation unit 760 described with reference to FIG.
4, 8, 16-value lev from B or 16VSB signal
The digital data is reproduced by the el slicer 757, and FIG.
131, 137, 156, and 157 of FIG.
lis Decoder 759b and ECC Decode
After error correction by the er759a, the digital HDTV signal is reproduced and output by the image decompressor of the image decoder 402.

As shown in FIGS. 160 (a) and 160 (b), the ECC encoder 744a
seed solomon Encoder 744j and I
ECC Dec using interleaver 744k
orderInter 759a has DeInterleaver75
9k and Reed solomon Decoder75
9j is used. As described in the previous embodiment, Interl
Applying eaves makes it more resistant to burst errors.

FIG. 128 (a) (b) (c) (d) (e)
By adopting the Trellis encoder shown in (f), the code gain can be further increased, and the error rate decreases. FIG. 172 in the case of 8VSB
As shown in Ratio2 / 3 Trellis en
Coder 744b and decoder 759b can be applied.

The embodiment has been described mainly with reference to an example in which a hierarchical digital TV signal is transmitted. In the case of the hierarchical type, ideal broadcasting can be performed. However, since the circuits of the image compression circuit and the modulator / demodulator become complicated, it is not preferable in terms of cost at the start of broadcasting. As described at the beginning of the fifth embodiment, 4VSB or 8VS
The signal point interval L of B = L _0, that is, equal intervals, non-hierarchical TV transmission is performed, and FIG.
With a simple configuration, a TV broadcasting system with a simple circuit is realized. And 8VSB at the stage of spread
May be switched to the hierarchical transmission.

Although 4VSB and 8VSB have been described above, FIGS. 159 (a) to 159 (d) show 16VSB and 3VSB.
2VSB will be described. FIG. 159 (a) is 16VS.
B shows the Constellation of B. FIG.
(B) is grouped into two signal point groups 722a to 722h, and is regarded as eight signal points, so that 8V
Since it can be handled as an SB, two-level hierarchical multi-level transmission is realized. In this case, Time Division Malti
Even if an 8VSB signal is intermittently transmitted by plex, hierarchical transmission is realized. However, in this method, the maximum data rate is 2/3. In FIG. 157 (c), there are four groups 723a to 723d, and the number of layers is further increased by one layer because the groups are handled as 4VSB. Also in this case, Time Divi
Even if the 4VSB signal is sent intermittently in the session multiplex, the maximum data rate is reduced but hierarchical transmission is realized. As described above, a three-layer hierarchical VSB is realized.

[0258] By this method, a hierarchical transmission is realized in which data of 8VSB or 4VSB can be reproduced when the C / N of 16VSB is deteriorated. FIG.
By doubling the signal point of 16VSB as shown in (d), 32VSB can be transmitted. If it is desired to increase the capacity of 16 VSB in the future, this method has an effect that a data capacity of 5 bits / symbol can be obtained while maintaining compatibility.

To summarize what has been described so far, FIG.
162 and the receiver shown in the block diagram of FIG.
Of the VSB transmitter shown in FIG.

Although the description has been made mainly using 4-VSB and 8-VSB, 16VSS as shown in FIGS. 159 (a), (b) and (c) is used.
B can be used for transmission. In the case of terrestrial broadcasting in the case of 16 VSB, a transmission capacity of 40 Mbps can be obtained in a 6 MHz band. However, the data rate of the HDTV digital compression signal is 15 to 18 when the MPEG standard is used.
Mbps, the transmission capacity margin becomes too large. As shown in FIG. 169, Redundancy: R ₁₆
= 100% or more, 1-channel digital HDT
To transmit V, the redundancy becomes too large and the circuit becomes complicated, but the effect is small for 8VSB. And 16VS for terrestrial broadcasting of HDTV on 2 channels
If B, the redundancy is the same as 4VSB, and only about 10b can be taken, so that a sufficient error correction code cannot be inserted, and the service area becomes narrow. 4-V as described above
Redundancy In SB: R ₄ = widely unable service area can not be sufficient error correction by 10-20%. As is clear from FIG. 169, sufficient error correction coding can be performed with 8-VSB Redundancy: R ₈ = 50%. The service area can be secured without increasing the circuit size of the error correction. Therefore digital H
Under the condition that DTV terrestrial broadcasting is performed with a band limitation of 6 to 8 MHz, as is clear from FIG.
It can be seen that -VSB is the most effective and optimal VSB modulation method.

In the third embodiment, an image engine as shown in FIG.
Although the coder 401 has been described, the block diagram of FIG.
It can be rewritten as 69. Content is exactly the same
Therefore, the description is omitted. Thus, the image encoding
The image 401 is a video separation circuit 40 such as a sub-band filter.
4, two 404a. These are referred to as a separation unit 794
70 is shown in the block diagram of the separation unit in FIG. Like one
The circuit is reduced by passing the signal through the separation circuit twice in a time-division manner.
Can be reduced. To explain this, in the first cycle, the input unit
HDTV and Super HDTV video signals from 403
The time axis is compressed and separated by the time axis compression circuit 795
By the circuit 404, H_HV_H-H, H_HV_L-H, H_LV_H−
H, H_LV_L+1 is divided into four components. in this case,
Switches 765, 765a, 765b, 765c
Position, and the compression unit 405 _HV_H-H, H_HV_L−
H, H_LV_H-H three signals are output. But H_L
V_LThe -H signal is output from the output 1 of the switch 765c on the time axis.
Input to the input 2 of the adjustment circuit 795,
The data is sent to the separation circuit 404 during the idle time of the time division processing,
H_HV_H, H_HV_L, H_LV_H, H_LV_LTo the four components
Divided and output. In the second cycle, switch 76
5, 765a, 765b, and 765c change to the output 2 position.
Therefore, the four components are sent to the compression unit 405. this
In this way, the configuration shown in FIG.
There is an effect that the number of separation circuits can be reduced.

Next, when such a three-layer hierarchical image transmission is performed, an image decoder as described with reference to the block diagram of FIG. 33 of the third embodiment is required on the receiver side. When this is rewritten, a block diagram as shown in FIG. 71 is obtained. There are two combiners 566 having the same configuration but different processing capabilities.

This takes the structure shown in FIG. 72 as shown in FIG.
In the same manner as in the case of the separation circuit of FIG. Referring to FIG. 72, five switches, 765a,
First, at timing 1, the switches 765, 765a, 765b, 765b, 765c, 765d
The input of 765c switches to 1. Then, first extending portion 522, a second extending portion 522a, the third extension portion 522b, each H _L V _L from the fourth extension portions _{522c, H L V H, H} H V L, H
_{The H} V _H signal is input to the corresponding input unit of the synthesizer 556 via the switch, and is subjected to a synthesis process to form one video signal. This video signal is sent to switch 765d and output 1
And output again to the input 2 of the switch 765c.
This video signal is originally a signal of H _L V _L -H components obtained by dividing a high resolution video signal. At the next timing 2, the switches 765, 765a, 765b, and 765c are switched to the input 2. Thus, this time H _H V _H −H, H _{H
V L -H, H L V H} -H , and H _L V _L -H signal combiner 5
The video signal is sent to a video signal 56, where the video signal is synthesized and one video signal is obtained. This video signal is output from the output unit 554 from the output 2 of the switch 765d.

As described above, when three layers of hierarchical broadcasting are received, there is an effect that two synthesizers are reduced to one by time division processing.

[0265] Now, this method, first, in the timing _{1 H H V H, H H} V L, H L V H, to enter the H _L V _L signal, H
The _L V _L -H signal is synthesized. After that, at timing 2 different from timing 1, H _H V _H −H, H _H V _L −
_H, H _L V H -H and to enter the above H _L V _L -H signal takes the steps of obtaining a final video signal. Therefore,
It is necessary to shift the timing of the two groups of signals.

If the timings of the components of the input signal are originally different or overlapping, the switches 765, 765a, and 766 are used to separate them in time.
It is necessary to provide a memory in 5b and 765c and accumulate them, and adjust the time axis. However, the transmission signal of the transmitter is
As described above, by transmitting the signals in a time-separated manner at timing 1 and timing 2, a time axis adjusting circuit is not required on the receiver side. Therefore, there is an effect that the configuration of the receiver is simplified.

[0267] D1 time layout of FIG. 73 shows a first data stream D1 of the transmission signal, H _L V _L by the D-channel for the duration of the timing _{1, H L V H, H} H V L, H H V Send _H signal,
H _L V _H -H at D2 channel during the timing 2, H
_H V _L -H, shows the time arrangement of signals when sending the _{H H} V _H -H. By transmitting the transmission signals in a temporally separated manner in this manner, there is an effect that the circuit configuration of the econcoder of the receiver is eliminated.

Next, the number of expansion units of the receiver is large. A method for reducing these numbers will be described. FIG. 74 (b) shows a time allocation diagram of transmission signal data 810, 810a, 810b, 810c. In this figure, different data 811, 810a, 811b, 811c are transmitted between data.
Then, the target transmission data is intermittently transmitted. Then, the second image encoder 422 shown in the block diagram of FIG.
The data is sequentially input to the extension unit 503 via the switch 21 and the switch 812. For example, after the input of the data 810 is completed, the decompression process is performed during the time of the separate data 811. After the processing of the data 810 is completed, the next data 810a is input. In this way, one decompressor 503 can be shared in a time-division manner in the same manner as in the case of the synthesizer. Thus, the total number of extension portions can be reduced.

FIG. 75 is a time allocation diagram when HDTV is transmitted. For example, NTS of the first channel of a broadcast program
Assuming that the _{HL VL} signal corresponding to the C component is _{HL VL} (1),
This is time-arranged at the position of the data 821 indicated by the bold line of the D1 signal. _{H L V H, H H V} L, H H V H signal D2 signal of the data 82 corresponding to the HDTV additional components of the first channel
1a, 821b, and 821c. Then, separate data 822, 822a, 822b, and 822, which are information of another TV program, are placed between all the data of the first channel.
Since c exists, the extension processing of the extension unit can be performed during this period. In this way, all the components can be processed in one extension unit. This method can be applied when the processing of the decompressor is fast.

A similar effect can be obtained by arranging data 821, 821a, 821b, 821c in D1 signal as shown in FIG. This is effective when transmission / reception is performed using transmission without a layer such as normal 4PSK or 4ASK.

FIG. 77 shows, for example, NTSC, HDTV and high-resolution HDTV, or low-resolution NTSC and NTSC.
And a time allocation diagram in the case of performing hierarchical multi-level broadcasting using a three-layer video such as HDTV and a physically two-layer hierarchical transmission system. For example, low resolution NTSC, NTSC and HD
When broadcasting three layers of TV images, the D1 signal has a low resolution N
H _L V _L signal corresponding to the TSC signal is placed in the data 821. Further, the separation signal NTSC _{H L} V H, H
_H V _{L, H} H V signals of each component of _H data 821a, 821
b, 821c. HDTV is a separation signal _{H L V H -H, H H} V L -H, H H V H -H signal are arranged data 823,823A, to 823b.

In this case, as shown in the block diagrams of FIGS. 156 and 170, the logical hierarchical transmission by differentiating the error correction capability described in the second embodiment is added to 4VSB, 8VSB and 16VSB. H _L D _L specifically uses a D _1-1 channel in the D ₁ signal. D _1-1 channel employs a high error correction method having greatly in correction capability than D _1-2 channel, as described in Example 2. D _1-1
Since channel redundancy is higher than the D _1-2 channel is low error rate after regeneration, other data 821
a, 821b, and 821c can be reproduced even under a lower C / N value. For this reason, even in a case where reception conditions are poor, such as in an area far from the antenna or in a car, a program can be reproduced with low-resolution NTSCTV quality. As described in the second embodiment, when viewed from the viewpoint of the error rate,
D ₁ data 821 in the D _1-1 channel in the signal D _1-2 other data in the channel 821a, 821
b, 821c, is more resistant to reception interference, is differentiated, and has a different logical hierarchy. As described in the second embodiment, D ₁ ,
D ₂ hierarchy said physical layer, the hierarchical structure by differentiating the error correcting code distance is said logical hierarchy.

The demodulation of the D ₂ signal requires a physically higher C / N value than the D ₁ signal. Therefore, C
/ The lowest reception condition of N values, i.e. H _L V _L signal, the low resolution NTSC signal is reproduced. Then, C / N value added in the next lower receiving condition _{H L V H, H H V} L, H H V H are reproduced, NTSC signal can be reproduced. In addition to the H _L V _L is high reception conditions of C / N values _{H L V H -H, H H} V L
-H, HDTV signals for also played _H H V _H -H is played. Thus, broadcasting of three layers can be performed. By using this method, the receivable area described with reference to FIG. 53 is expanded from two layers to three layers as shown in the reception interference area diagram of FIG. 90, and the program receivable area is further expanded.

FIG. 78 is a block diagram of the third image decoder in the case of the time arrangement shown in FIG. Basically Figure 7
The block diagram of FIG. 74 is obtained by adding the configuration of the block diagram of FIG. 74A to the configuration in which the third input unit 551 of the D3 signal is omitted from the block diagram of FIG.

In operation, at timing 1, the D1 signal is input from the input unit 521 and the D2 signal is input from the input unit 530. Since the components such as H _L V _H are temporally separated, they are sequentially and independently sent to the expansion unit 503 by the switch 812. This sequence will be described with reference to the time allocation diagram of FIG. First, the _{HL VL} compressed signal of the first channel enters the decompression unit 503 and is decompressed. Then the first channel of _{H L V H, H H V} L, is _H H V _H are expanded processed, via the switch 812a is input to a predetermined input of the combiner 556 is combining processing, first, H _L The _VL- H signal is synthesized. This signal is input from the output 1 of the switch 765a to the input 2 of a switch 765, is input to the H _L V _L input of the combiner 556.

[0276] In the next timing 2, the D2 signal, as shown in the time arrangement of FIG _{77 H L V H -H, H} H V L -
_H, H H V H -H signal is inputted is extended by extension 503, the signal through the switch 812a is combiner 556
, And are subjected to a synthesis process to output an HDTV signal. The HDTV signal is output from the output 2 of the switch 765a via the output unit 521. As described above, transmission by the time arrangement shown in FIG. 77 has an effect of greatly reducing the number of decompressing units and the number of combiners of the receiver. Incidentally, FIG. 77 shows D1,
Although the two stages of the D2 signal are used, the use of the above-described D3 signal enables high-definition HDTV and TV broadcasting of four layers.

FIG. 79 is a time allocation diagram of a hierarchical broadcast for broadcasting three hierarchical images using three physical layers D1, D2, and D3. As is clear from the figure, the components of the same TV channel are arranged so as not to overlap in time.
FIG. 80 shows a receiver in which the third input unit 521a is added to the receiver described in the block diagram of FIG. Broadcasting according to the time arrangement in FIG. 79 has the effect that the receiver can be configured with a simple configuration as shown in the block diagram in FIG.

The operation is almost the same as the time allocation diagram of FIG. 77 and the block diagram of FIG. Therefore, description is omitted.
Also, as shown in the time allocation diagram of FIG. 81, all signals can be time-multiplexed to the D1 signal. In this case, the data 821
Data 821a and 8
The error correction capability is higher than 12b and 821c. For this reason, the hierarchy is higher than other data. As described above, physically one layer but logically two.
Hierarchical transmission of layers. Further, another data of another program channel 2 is included between the data of the program channel 1. Therefore, serial processing can be performed on the receiver side, and the same effect as that in the time allocation diagram of FIG. 79 can be obtained.

In the case of the time allocation diagram shown in FIG. 81, the data has a logical hierarchy. By reducing the transmission bit rate of data 821 and separate data 822 to に or ３, the transmission time of this data is reduced. Since the error rate of the data is reduced, physical hierarchical transmission can be performed. In this case, there are three physical layers.

FIG. 82 is a diagram similar to that of FIG.
Image decoder 4 for transmitting only data string D1 signal
The block diagram of FIG. 23 has a simpler configuration than the image decoder shown in the block diagram of FIG. The operation is shown in FIG.
The description is omitted because it is the same as the image decoder described above.

As described above, when a transmission signal as shown in the time allocation diagram of FIG. 81 is transmitted, there is an effect that the number of decompressor 503 synthesizers 556 can be greatly reduced as shown in the block diagram of FIG. In addition, since the four components are temporally separated and input, the combiner 556, that is, the image combining unit 5 in FIG.
By changing the connection of the internal 48 circuit blocks according to the input image components, some blocks can be shared in a time-sharing manner and the circuit can be omitted.

As described above, there is an effect that the receiver can be configured with a simple configuration. In the fifth embodiment, the AS
Although the operation has been described using K modulation, many of the methods described in the fifth embodiment use the PSK or QA described in the first, second, and third embodiments.
It can also be used for M modulation.

The embodiments described above can also be used for FSK modulation. For example, as shown in FIG. 83, f1, f2, f3, f4
When performing multi-level FSK modulation, hierarchical transmission can be performed by performing grouping as shown in the signal point arrangement diagram of FIG. 58 of the fifth embodiment and separating signal point positions of each group.

In FIG. 83, a frequency group 841 of frequencies f1 and f2 is defined as D1 = 0, and a frequency group 842 of frequencies f3 and f4 is defined as D1 = 1. And f1, f3
Is defined as D2 = 0, f2 and f4 are defined as D2 = 1, as shown in the figure, 1-bit each of D1 and D2, that is, 2-bit hierarchical transmission is possible. For example, when C / N is high, t = t
3, D1 = 0 and D2 = 1 can be reproduced, and at t = t4, D1 = 1 and D2 = 0 can be reproduced. Next, when C / N is low, only D1 = 0 can be reproduced at t = t3, and only D = 1 can be reproduced at t = t4. Thus, hierarchical transmission of FSK can be performed. The hierarchical multilevel transmission method of FSK can be used for the hierarchical broadcasting of the video signal described in the third, fourth, and fifth embodiments.

Also, the magnetic recording / reproducing apparatus shown in the block diagram of FIG. 84 can use the fifth embodiment of the present invention. In the fifth embodiment, magnetic recording and reproduction can be performed because of ASK.

FIG. 84 shows a recording apparatus (Recorder) / transmitter (Transmitter) and a reproducing apparatus (Play).
FIG. 2 shows a block diagram of an er) / receiver (Receiver).

In the block diagram of FIG. 84, the transmitter 1,
The VSB-ASK modulation method according to the fifth embodiment of the receiver 43 uses the transmission circuit 5a of the transmitter 1 for the recording device magnetic recording signal amplifier 85.
By replacing the receiving circuit 24a of the receiver 43 with the magnetic reproduction signal amplifier 857b, the configuration becomes exactly the same. In the text, since the ASK signals are all VSB-ASK in the transmission apparatus, the VSB-ASK signal will be omitted as the ASK signal.

Explaining the operation of FIG. 84, the HDTV signal is compressed by the video encoder 401 and then
The first data string is error-coded by an ECC encoder 743a, and the second data string is ECC7
After error encoding at 44a, Trellis Enc
trellis-encoded by the order 744b and VS
Enter the Modulator 749 of B-ASK. Rec
Offset Generator8 for order
56, an offset signal is added, and the recording circuit 8
53, on the magnetic tape 855. Offset for Transmitter1 of the transmission device
The DC offset voltage is superimposed on the ASK signal by the generator 856, and the Up converter 5a
Sent by Carrier reproduction by the receiver 43 is facilitated by the DC offset. The transmitted VSB-ASK signals of 4VSB, 8VSB, and 16VSB are received by the antenna 32b and input to the demodulator 852a via the receiving circuit 24a.

On the other hand, the recording signal recorded by the recording device is reproduced by the reproducing head 854a and sent to the demodulator 852b via the reproducing circuit 858.

The signal input to demodulator 852b passes through filter 858a of demodulator 852b, and is demodulated by ASK demodulator 852b such as VSB described above. The first data string of the demodulated signal is error-corrected by an ECC decoder 758a, and the second data string is a Trellis decoder 75.
9b and error correction by the ECC decoder 759a. The video decoder 402 expands the video signal and outputs an HDTV, TV signal or SDTV signal.

Although the circuit is complicated by the addition of the Trellis encoder, the error rate is reduced, the transmission distance of the transmission device is increased, and the image quality of the recording / reproducing device is improved. In this case, the Filter 858a of the receiver 43 corresponds to FIG.
By using a comb-type filter 760a having a filter characteristic for eliminating the main carrier, video carrier, and audio carrier of the analog TV signal as shown in FIG. 4, interference of the analog TV signal can be eliminated, and the error rate can be reduced. . In this case, if a filter is always inserted even when there is no interference, the received signal deteriorates. To avoid this, as shown in FIG. 65, the error rate detection unit 782 turns on the analog TV filter 760a only when the signal is degraded due to the interference of the analog TV, and turns off the filter when there is no interference. Signal deterioration due to the above can be prevented.

Also, in the case of FIG. 84, after the first data string and the second data string, the second data string has a lower error rate. Therefore, by transmitting / recording important High Priority (HP) information such as the descrambling information of FIG. 66 and the header information of the image data of each image block in the second data string, the descrambling and each image can be performed. The image signal reproduction of the block can be stabilized.

As shown in FIGS. 137 and 172, 8 V
In an SB or 16VSB transmission apparatus, the data sequence of each time-divided sub-channel is changed for each sub-channel by an error correction code gain of a trellis decoder or an ECC decoder, and High Priority (HP) information is changed to a higher code gain. Sent by sub-channel. Since the error rate of the HP information becomes low, noise is generated to some extent in the transmission path, and the signal is degraded.
An effect is obtained in that even if the originality information (LP) information is destroyed, the data of the HP information is not destroyed. By transmitting the aforementioned descramble information or header information such as the address of a data packet in image block units as HP information, the descrambling is stabilized for a long time, and the viewer can view the descrambled program stably. Further, since the catastrophic destruction of each image block is prevented, even if the received signal is deteriorated, the whole image quality is only deteriorated, so that the viewer can watch the TV program with a certain image quality.

(Embodiment 6) An example in which the transmission recording method of the present invention is applied to a magnetic recording / reproducing apparatus according to a sixth embodiment will be described. In the fifth embodiment, the case where the present invention is applied to the ASK transmission system of multi-level transmission has been described. Can be applied. In addition to ASK,
By applying the C-CDM method of the present invention to PSK, FCK, and QAM, hierarchical and non-hierarchical multivalued magnetic recording can be performed. As described above, the present invention can be applied to both a recording device and a transmission device. However, the present invention will be described using an example of a recording device.

First, a method of hierarchization and multi-leveling will be described using an example in which the C-CDM system of the present invention is applied to a 16QAM or 32QAM magnetic recording / reproducing apparatus. FIG. 84 illustrates the transmission / recording apparatus using 9-ASK such as multi-level VSB in the fifth embodiment. However, the same effect can be obtained by changing the ASK of FIG. 84 to QAM. 84 and 173, Q
A case where C-CDM is applied to AM will be described. Below QA
M obtained by C-CDM multiplexing is referred to as SRQAM. 137 and 154 illustrate a case where the present invention is applied to a transmission system.

Referring to FIG. 84 and FIG. 173, the magnetic recording / reproducing apparatus 851 converts the input video signal such as HDTV into a high-band signal and a low-band signal by the first video encoder 401a and the second video encoder 401b of the video encoder 401. high separated compressed, containing a low-frequency video signal, such as H _L V _L components in a first data stream input unit 743 in the input unit 742, H _H V _H components such as the second data stream input unit 744 The video signal is input to the modulation unit 749 in the modulator / demodulator 852.
In the first data string input unit 743, the error correction code is E
It is added to the low frequency signal in the CC unit 73a. On the other hand, the second data string input to the second data string input unit 744 is 1
In the case of 6 SRQAM, 36 SRQAM, and 64 SRQAM, they are 2 bits, 3 bits, and 4 bits. This signal is error-coded by the ECC 744a and then 16SRQAM, 32SRQ by the Trellis encoder 744b.
In the case of AM and 64 SRQAM, FIG.
The Trellis Encoder 744b shown in FIG.
/ 2, 2/3, and 3/4 are Trellis encoded.
For example, in the case of 64 SRQAM, the first data string is 2 bits
Thus, the second data string becomes 4 bits. Therefore, FIG.
Using TrellisEncoder 744b as shown in (c), 3
Trellis E of Ratio 3/4 with 4 bit bit data
Perform ncode. In the case of 4ASK, 8ASK, and 16ASK, 1/2, 2/3, and 3/4 trellis encoding is performed independently. In this way, the redundancy is increased and the data rate is reduced, while the error correction capability is increased, so that the error rate of the same data rate can be reduced. For this reason, a substantial information transmission amount of the recording / reproducing system or the transmission system increases. In the case of the 8VSB transmission system described in the fifth embodiment, the transmission rate is 3 bits / symbol.
(B) Trellis Encode of Ratio2 / 3 shown in (e)
r744g and Trellis Decoder 744q can be used, and the overall block diagram is as shown in FIG. However, Trellis
Encode is not used for the first data string originally having a low error rate in the block diagram of FIG. 84 of the sixth embodiment because the circuit becomes complicated. Although the second data string has a smaller inter-code distance and a lower error rate than the first data string, Trellis encoding of the second data string improves the error rate. The configuration in which the Trellis encoding circuit for the first data string is omitted has an effect that the entire circuit becomes simpler. The modulation operation is almost the same as that of the transmitter in the fifth embodiment shown in FIG. The signal modulated by the modulator 749 is AC-biased by the bias generator 856 in the recording / reproducing circuit 853, amplified by the amplifier 857a, and recorded on the magnetic tape 855 by the magnetic head 854.

[0297] with information is recorded in the main signal 859 for example 16SRQAM of having a frequency fc becomes the carrier as shown in a recording signal frequency arrangement diagram of a format of the recording signal Figure 113, the frequency of 2 times the 2f _c in f _c pilot f _p signal 859a having is recorded simultaneously. Frequency f
_Since the magnetic recording is performed by applying the AC bias by the bias signal 859b of _BIAS , distortion during recording is reduced. Since the multi-level recording of two layers out of the three layers shown in FIG. 113 is performed, the threshold for recording and reproduction is Th-1-2, Th-1-2.
There are two of them. Two layers all if the signal 859 by the recording and reproducing of the C / N level of only D ₁ if the signal 859C is recorded and reproduced.

When 16 SRQAM is used for the main signal, the signal point arrangement is as shown in FIG. FIG. 100 shows a case where 36 SRQAM is used. 4ASK, 8ASK
Are used, the arrangement is as shown in FIGS. 58 and 68 (a) and (b). When reproducing this signal, the magnetic head 854
, The main signal 859 and the pilot signal 859a are reproduced and amplified by the amplifier 857b. From this signal, the filter 858a of the carrier recovery circuit 858 makes 2f _o
Pilot signal f _p is frequency separated, 1/2-minute carriers of f _o is the frequency divider 858b is reproduced demodulator 760 comprising
Sent to The demodulation unit 76 uses the reproduced carrier wave.
At 0, the main signal is demodulated. At this time, when a magnetic recording tape 855 having a high C / N value for HDTV or the like is used, it becomes easy to discriminate each of the 16 signal points, so that the demodulation unit 7 is used.
At 60, both D1 and D2 are demodulated. Then, all signals are reproduced by the image decoder 422. HDTV
In the case of a VTR, for example, a 15 Mbps HDTV high bit rate TV signal is reproduced. Video tapes with lower C / N values have lower costs. At present, there is a difference of 10 dB or more between the commercially available VHS tape and the high C / N type tape for broadcasting. When an inexpensive video tape 855 with a low C / N value is used, it is difficult to discriminate all 16-value and 36-value signal points because the C / N value is low. Therefore, the first data string D1 can be reproduced, but the 2-bit, 3-bit or 4-bit data string of the second data string D2 cannot be reproduced, and only the 2-bit data string of the first data string is reproduced. When a two-layered HDTV image signal is recorded and reproduced, a high-frequency image signal is not reproduced on a low C / N tape, so a low-rate low-frequency image signal of the first data stream, specifically, for example, a 7 Mbps wide signal An NTSC TV signal is output.

As shown in the block diagram of FIG. 114, the second data string output section 759, the second data string input section 744, and the second image decoder 422a are omitted, and the first data string D ₁
A low bit rate dedicated recording / reproducing device 851 having a modulator such as a modified QPSK that modulates and demodulates only the data can be set as one product form. This device can record and reproduce only the first data string. That is, image signals of wide NTSC grade can be recorded and reproduced. When a video tape 855 outputting a high C / N value on which a high bit rate signal such as the HDTV signal is recorded is reproduced by the low bit rate dedicated magnetic recording / reproducing apparatus, only the D1 signal of the first data string is output. Is reproduced, a wide NTSC signal is output, and the second data string is not reproduced. That is, when the video tape 855 on which the HDTV signal of the same hierarchical type is recorded is reproduced, the HDTV signal can be reproduced by the recording / reproducing apparatus having one complicated configuration, and the wide NTSCTV signal can be reproduced by the recording / reproducing apparatus having the simple configuration. In other words, in the case of two layers, there is a great effect that complete compatibility of four combinations is realized between tapes having different C / N values and models having different recording / reproducing data rates. In this case, NT compared to the HDTV dedicated machine
The SC dedicated machine has a remarkably simple configuration. Specifically, for example, the circuit size of the EDTV decoder is 1/6 of that of the HDTV decoder. Therefore, a low-function machine can be realized at a very low cost. As described above, it is possible to realize two types of recording / reproducing devices having different recording / reproducing abilities of the image quality of HDTV and EDTV, so that there is an effect that a model in a wide price range can be set. Also, the user can freely select a tape from a high-priced high C / N tape to a low-priced low C / N tape each time according to the required image quality. In this way, extensibility can be obtained while completely maintaining compatibility, and compatibility in the future can be secured. Therefore, it is possible to realize a standard of a recording / reproducing apparatus which will not become obsolete in the future. As another recording method, hierarchical recording by phase modulation described in the first and third embodiments can also be performed.

[0300] Recording by ASK described in the fifth embodiment can also be performed. 59 (c) (d)
As shown in FIGS. 68 (a) and 68 (b), signal points of quaternary ASK or octal ASK can be divided into two groups, and two layers and three layers can be formed.

The block diagram in the case of ASK is the same as FIG. As shown in FIG. Trellis and AS
The error rate is reduced by the combination of K. In addition to the description in the embodiment, multi-level recording such as a hierarchical type using multiple tracks on a magnetic tape can also be performed. Also, by changing the error correction capability,
Logical hierarchical recording by differentiating data is also possible.

Here, compatibility with future standards will be described. Normally, when a standard of a recording / reproducing apparatus such as a VTR is set, the standard is determined by using the highest C / N tape that can be actually obtained. The recording characteristics of the tape improve with the progress of the day. For example, the C / N value is currently improved by 10 dB or more compared to a tape 10 years ago. In this case, 10
When a new standard is set when the tape performance is improved in the future after 20 to 20 years, it is very difficult for the conventional method to be compatible with the old standard. For this reason, the old and new standards were often incompatible or incompatible.

However, in the case of the present invention, first, a standard for recording and reproducing the first data string or the second data string on the current tape is created. Next, when the C / N of the tape is greatly improved in the future, if the present invention is adopted in advance, data of a higher data layer, for example, data of a third data string is added, for example, 3
A super HDTV VTR that records and reproduces 64 SRQAM and 8ASK in the hierarchy is realized while maintaining complete compatibility with the conventional standard. At the time when this future standard was realized, the present invention, a two-layer magnetic recording of the old standard, capable of recording and reproducing only the first data line and the second data line on the magnetic tape on which the three layers were recorded up to the third data line by the new standard When the data is reproduced by the reproducing apparatus, the third data string cannot be reproduced, but the first and second data strings can be completely reproduced. Therefore, the HDTV signal is reproduced. Therefore, there is an effect that the recording data amount can be expanded in the future while maintaining compatibility between the old and new standards.

Now, let us return to the description of the reproducing operation in FIG. At the time of reproduction, a reproduction signal is reproduced from the magnetic tape 855 by the magnetic head 854 and the magnetic reproduction circuit 853, and the modem 852
Send to The operation of the demodulation unit is substantially the same as that of the first, third, and fourth embodiments, and a description thereof is omitted. The first data sequence D1 and the second data sequence D2 are reproduced by the demodulation unit 760, and the second data sequence is
By Trellis-Decoder 759b such as Vitabi decoder, c
Error correction is performed with high ode gain, and the error rate is reduced. The D1 and D2 signals are demodulated by the image decoder 422, and an HDTV video signal is output.

The above is a magnetic recording / reproducing apparatus having two layers.
Next, one logical layer is added to two physical layers.
FIG. 1 shows an embodiment of a magnetic recording / reproducing apparatus having a three-layer structure including additional layers.
This will be described with reference to the block diagram of FIG. Basically, the figure
84, but the first data string is obtained by TDM.
It is further divided into two sub-channels and has a three-layer structure
You. As shown in FIG. 131, first, the HDTV signal is
1-1st image encoder 4 in image encoder 401a
01c and the 1-2nd image encoder 401d,
And two data of the low-frequency video signal, D_1-1And D1_-Separated into two
Then, the data is input to the first data string input unit of the input unit 742.
Data string D of MPEG grade image quality_{1- 1}Is ECC coder 7
43a, error correction coding with high code gain
D1_-2 is a normal code gai in ECC Coder 743b.
Error correction coding with n is performed. D _1-1And D1_-2 is TD
Time multiplexed by the M unit 743c to form one data string D
₁Becomes D₁And D2 are modulated by the C-CDM modulator 749.
The magnetic head 854 forms two layers on the magnetic tape 855.
Is recorded hierarchically.

[0306] During reproduction, the recording signal reproduced by the magnetic head 854, the same operation as described in FIG. 84, is demodulated into D ₁ and D2 by C-CDM demodulator 760. The first data sequence D ₁ is transmitted to two sub-channels D in the TDM unit 758 c in the first data output unit 758.
_1-1 and D1 _- 2 is demodulated into. D _1-1 having a high Code gain ECC
In Decoder758a, to be error-corrected, D1 _- 2
D _1-1 is demodulated even at a low C / N value,
The LDTV is decoded and output by the image decoder 402a. Meanwhile D1 _- 2 normal ECC Decoder7 of Code gain
Since the error correction at 58b, D1 _- signal level due to its threshold value of 1 in comparison the high C / N can not be played not larger. Then, demodulated in the 1-2 image encoder 402d, is combined with D _1-1, EDTV wide NTSC grade is outputted.

The second data string D2 is Trellis Decoder 759.
b by a Vitabi decoded, error corrected by ECC759a, the second image encoder 402b becomes a high-frequency image signal, D _1-1, D1 _- are 2 Synthesis HDTV it is outputted. The threshold of the C / N of D ₂ in the case D1 _- greater than 2 sets. Thus if C / N value of the tape 855 is small, D _1-1 clogging LDTV is reproduced, if the normal C / N value of the tape 855 D _1-1, D1 _- 2 clogging EDTV is reproduced, C / N having a high tape 855 its value when D _1-1, D1 _- 2, D2, that the HDTV signal is reproduced.

Thus, a three-layer magnetic recording / reproducing apparatus is realized. As described above, there is a correlation between the C / N value of the tape 855 and the cost. In the case of the present invention, the user can record and reproduce image signals of three grades of image quality according to the three types of tape costs.
There is an effect that the range of selecting the grade of the tape according to the content of the program is expanded.

[0309] Next, as shown in the recording track diagram of FIG.
A recording track 855b having an azimuth angle B opposite to the recording track 855a having an azimuth angle A is recorded on 55. The left recording area 855c in the center of the recording track 855a as shown is provided, the other region and D _1-2 recording region 855D. This is provided in at least one place for each of several recording tracks. In this, one LDTV frame is recorded. The D2 signal of the high frequency signal is recorded in the D2 recording area 855e of the entire area of the recording track 855a. At the time of normal speed recording and reproduction, this recording format has no new effect. Now, at the time of tape fast forward reproduction in the forward and reverse directions, the magnetic head trace 855f of the azimuth angle A does not coincide with the magnetic track as shown in the figure. It is provided with a D _1-1 recording region 855c set in the narrow region of the tape center portion in the present invention shown in FIG. 132. Thus, with a certain probability, this area is reliably reproduced. MPE is from the reproduced D _1-1 signal
It is possible to demodulate an image of the entire screen at the same time, although the image quality is the same as that of the LDTV of G1. In this way, at the time of fast-forward reproduction, when several to several tens of complete images of the LDTV are reproduced per second, there is a great effect that the user can confirm the picture screen during fast-forward.

At the time of reverse playback, the head trace 85
As shown in g, only a part of the magnetic track is traced. However, even in this case, when the recording / reproducing format shown in FIG. 132 is used, the D1-1 recording area can be reproduced, so that a moving image of LDTV grade image quality is output intermittently.

As described above, according to the present invention, since an LDTV-grade image is recorded in a narrow area of a part of a recording track, a user can intermittently complete an almost complete still image with the LDTV-grade image quality at the time of fast forward in both the forward and reverse directions. Since reproduction is possible, there is an effect that the screen can be easily confirmed at the time of high-speed search.

Next, a method corresponding to higher speed fast-forward playback will be described. As shown in the bottom right of Figure 132 provided D _1-1 recording region 855C, and records one frame of ldtv D _1-1 Some more narrow region of the D _1-1 · D ₂ recording recording area 855C An area 855h is provided. Some of the information in one frame of LDTV is recorded in the subchannel D _1-1 in this region. D ₂ recording region 855j of the remaining information of ldtv D _1-1 · D ₂ recording region 855h
To be duplicated. Subchannel D ₂ has a three to five times of the data recording amount of subchannel D _1-1. Therefore D
_1-1 and LDTV on the tape of the area of D ₂ 1 / 3-1 / 5
Of one frame can be recorded. Region head race is even narrower region 855H, since that can be recorded in 855J, also becomes 1 / 3-1 / 5 area greater time than the head trace time T _s1. Therefore, even if the rapid traverse speed is increased and the trace of the head is further inclined, the probability of tracing the entire area increases. Intermittently to play further 3-5 times faster complete LDTV images even during fast-forward than in the case of this for D _1-1 only.

[0313] In this manner the case of two hierarchies VTR, since there is no function of reproducing the D ₂ recording region 855J, can not be reproduced during high-speed fast-forward. On the other hand, in a high-performance VTR having three layers, an image can be confirmed even at a fast forward speed 3 to 5 times faster than that in the two layers. In other words, a VTR having a different maximum fast-forward speed that can be reproduced according to the cost as well as the number of layers, that is, the image quality according to the cost is realized.

[0314] In the embodiment, the hierarchical modulation method is used. However, even in a normal modulation method such as 16QAM, fast-forward reproduction according to the present invention can be realized by performing hierarchical image coding. Needless to say.

In the conventional non-hierarchical digital VTR recording method of the high image compression method, since the image data is uniformly distributed, the entire screen image of the same time in each frame is reproduced during fast forward reproduction. I can't. For this reason, it is possible to reproduce only the image of each block on the screen whose time axis is shifted. However, although the hierarchical HDTV VTR of the present invention is of the LDTV grade, there is an effect that an image in which the time axis of each block on the screen is not shifted can be reproduced at the time of fast forward reproduction.

In the case of performing three-layer recording of the HDTV of the present invention, when the C / N of the recording / reproducing system is high, a high-resolution TV signal such as an HDTV can be reproduced. And the C /
When N is low or reproduction is performed by a magnetic reproducing device having a low function, an EDTV grade TV signal such as wide NTSC or an LDTV grade TV signal such as low resolution NTSC is output.

As described above, in the magnetic reproducing apparatus according to the present invention, even when the C / N is low or the error rate is high, the video of the same content is reproduced with low resolution or low image quality. The effect that it can be obtained is obtained.

(Embodiment 7) In Embodiment 7, the present invention is used for video hierarchy transmission of four layers. By combining the four-layer transmission scheme and the four-layer video data structure described in the second embodiment, the four-layer transmission scheme is used as shown in the reception block diagram in FIG.
A layer reception area is created. As shown in the figure, a first reception area 890a is formed on the innermost side, and a second reception area 890b, a third reception area 890c, and a fourth reception area 890d are formed outside the first reception area 890a.
A method for realizing the four layers will be described.

To realize four layers, there are a four-layer physical layer by modulation and a four-layer logical layer by differentiating the error correction capability. C / N is required. The latter is based on the premise that demodulation is possible, so that the C / N difference between layers cannot be made large. It is realistic to perform four-layer transmission using two physical layers and two logical layers. Then
First, a method of separating a video signal into four layers will be described.

FIG. 93 is a block diagram of the separating circuit 3. The separating circuit 3 comprises a video separating circuit 895 and four compression circuits. The basic configuration inside the separation circuits 404a, 404b, and 404c is similar to that of the first image encoder 40 shown in FIG.
1 is the same as the block diagram of the separation circuit 404 in FIG. The isolation circuit 404a like the video signal low frequency component H _L V _L and highband components _H H V _H and the intermediate component _{H H} V _L, 4 of H _L V _H
Split into two signals. In this case, H _L V _L is the resolution becomes half of the original video signal.

The input video signal is supplied to the video separation circuit 40.
4a divides the high-frequency component and the low-frequency component into two. Since the image is divided in the horizontal and vertical directions, four components are output. The dividing point of the high band and the low band is at the middle point in this embodiment. Therefore, when the input signal is a 1000 vertical HDTV signal, H
_L V _L signal of 500 vertical, a horizontal resolution of a half TV signal.

The H _L V _L signal of the low frequency component is separated by the separation circuit 404c.
As a result, the horizontal and vertical frequency components are further divided into two. Therefore H _L V _L outputs, for example 250 lines vertically, the horizontal resolution is 1/4. When this is defined as an LL signal, the LL component is compressed by the compression unit 405a and output as a _D1-1 signal.

On the other hand, the three components of the high frequency components of H _L V _L are combined into one LH signal by the combiner 772c,
5b, and is output as a _D1-2 signal. In this case, three compression units may be provided between the separation circuit 404c and the synthesizer 772c.

H of high frequency component_HV_H, H_LV_H, H_HV_LOf 3
One H is obtained by the synthesizer 772a. _HV_H-H signal
You. If there are 1000 compressed signals both vertically and horizontally, this signal
The signal has 500 to 1000 components in the horizontal and vertical directions.
One. Then, it is separated into four components by the separation circuit 404b.
It is.

[0325] Thus the horizontal as H _L V _L outputs, 500 to 750 pieces of components in the vertical direction are separated. This is called an HH signal. Then _{H H V H, H L V} H, 3 components of _H H V _L 7
It has 50 to 1000 components, is synthesized by a synthesizer 772b, becomes an HH signal, is compressed by a compression unit 405d, and has
Output as _2-2 signal. On the other hand, the HL signal is output as a _D2-1 signal. Accordingly LL, i.e. D _1-1 signal, for example 0 This 250 present the following ingredients, LH clogging D _1-2 signal is 250 or more 500 or less of the frequency component HL clogging D
_{The 2-1} signal has a frequency component of 500 or more and 750 or less, and the HH, that is, the _D2-2 signal has a frequency component of 750 or more and 1000 or less. This separation circuit 3 has an effect that a hierarchical data structure can be formed. By using the separation circuit 3 of FIG. 93 to replace the part of the separation circuit 3 in the transmitter 1 of FIG. 87 described in the second embodiment, four-layer hierarchical transmission can be performed.

By combining the hierarchical data structure and the hierarchical transmission in this way, it is possible to realize an image transmission in which the image quality gradually decreases as the C / N deteriorates. This has the great effect of expanding the service area in broadcasting.
Next, the receiver for demodulating and reproducing this signal has the same configuration and operation as the second receiver in FIG. 88 described in the second embodiment. Therefore, the entire operation is omitted. However, the configuration of the synthesizing unit 37 differs from that of data transmission because it handles video signals. Here, the combining unit 37
Will be described in detail.

As described in the second embodiment with reference to the block diagram of the receiver in FIG. 88, the received signal is demodulated and error-corrected, and D _1-1 , D _1-2 , D _2-1 , D _{2-1 2-2-4}
And is input to the synthesizing unit 37.

FIG. 94 is a block diagram of the synthesizing unit 33.
is there. D entered_1-1, D_1-2, D _2-1, D_2-2The signal is extended
In the long parts 523a, 523b, 523c, 523d
LL and L which have been expanded and described in the separation circuit of FIG.
H, HL, and HH signals. This signal is the original video signal
If the horizontal and vertical bands are 1, LL is 1/4 and L
L + LH is 1/2, LL + LH + HL is 3/4, LL +
LH + HL + HH is one band. LH signal is a separator
531a, the image synthesizing unit 548a outputs L
The H signal of the image combining unit 548c is synthesized with the L signal._LV_LTo the terminal
Is entered. Regarding the description of the example of the image combining unit 531a,
Since the description has been given for the image decoder 527 in FIG. 32, the description is omitted.
On the other hand, the HH signal is separated by the separator 531b,
This is input to the synthesis unit 548b. The HL signal is output from the image synthesizing unit 5.
At 48b, the signal is synthesized with the HH signal._HV_H-H signal and
The image is separated by the separator 531c and the image
c, the video signal is synthesized with the synthesized signal of LH and LL.
And output from the combining unit 33. And the second in FIG.
The signal is output as a TV signal at the output unit 36 of the receiver. this
In the case, the original signal is 1050 vertical, about 1000 HDT
If it is a V signal, the four reception conditions shown in the reception interference diagram of FIG.
Depending on the case, TV signals of four image quality are received.

The image quality of the TV signal will be described in detail. Figure 91
FIG. 86 is combined with FIG. 86 to form a transmission hierarchical structure diagram of FIG. Thus, the reception area 86 is improved with the improvement of the C / N.
D _1-1 in 2d, 862c, 862b and 862a,
Hierarchical channels that can be successively reproduced such as D _1-2 , D _2-1 and D _2-2 are added to increase the data amount.

In the case of hierarchical transmission of video signals, as shown in the transmission hierarchical structure diagram of FIG. 95, LL, LH, H
The hierarchical channels of the L and HH signals are reproduced. Therefore, as the distance from the transmitting antenna decreases, the image quality improves. LL signal when L = Ld, L when L = Lc
L + LH signal, when L = Lb, LL + LH + HL signal, L
When = La, the LL + LH + HL + HH signal is reproduced.
Therefore, if the band of the original signal is 1, １ ／, 、 ３, 3
/ 4, 1 band image quality can be obtained in each receiving area. If the original signal is an HDTV with 1000 vertical scanning lines, 250
, 500, 750, and 1000 TV signals are obtained. In this way, hierarchical video transmission in which image quality gradually deteriorates becomes possible. FIG. 96 shows a conventional digital HDTV.
It is a reception interference figure in the case of a broadcast. As is apparent from the figure, in the conventional system, the reproduction of the TV signal becomes completely impossible when CN is equal to or lower than V _O. Therefore, even within the service area distance R, reception is not possible as shown by the mark x in a competing area with another station, a building shadow, or the like. FIG. 97 is a reception state diagram of the HDTV hierarchical broadcast using the present invention. As shown in FIG. 97, C / N = a at distance La, C / N = b at Lb, and C / N = C at Lc.
C / N = d for c and Ld, 250 for each receiving area
Image quality of 500, 750, and 1000 lines can be obtained. C / N is inferior even within the distance La, and there are areas where reproduction cannot be performed with the HDTV image quality itself. However, even in that case, reproduction can be performed even if the image quality is deteriorated. For example, at the point B of the building, there are 750 trains, and at the point D on the train, 25
0 points, 750 points at the F point where the ghost is received, 250 points at the G point in the car, and 250 points at the L point, which is a competitive area with other stations, can be reproduced. As described above, by using the hierarchical transmission according to the present invention, it is possible to receive even in an area where reception and reproduction cannot be performed by the conventionally proposed method, and there is a remarkable effect that the service area of the TV station is greatly expanded. . Also, broadcast program D of the same program as the analog broadcasting in the area at D _1-1 channel, as shown in hierarchical transmission of FIG 98, D _1-2, D _2-1, another with D _2-2 channel Broadcasting programs C, B, and A in this manner, it is possible to reliably broadcast the simulcast of program D in all regions, and to provide the effect of multi-program broadcasting by serving the other three programs while fulfilling the role of simulcast. Can be

Embodiment 8 Hereinafter, a seventh embodiment will be described with reference to the drawings. Embodiment 8 is an embodiment in which the hierarchical transmission system of the present invention is applied to a transceiver of a cellular telephone system. Data D ₁ of the hierarchy the call's voice input through the microphone 762 as described above by the compression unit 405 in the block diagram of a transceiver of the mobile telephone of FIG. 115, D _2, D ₃
The time division unit 765 time-divides the signal into predetermined time slots based on the timing, and receives a hierarchical modulation such as the above-described SRQAM in the modulator 4.
One carrier is transmitted from the antenna 22 via the antenna duplexer 764, is received by a base station described later, is transmitted to another base station or a telephone station, and can communicate with another telephone.

On the other hand, a communication signal from another telephone is received by the antenna 22 as a transmission radio wave from the base station. This received signal is demodulated as D ₁ , D ₂ , and D ₃ data in a hierarchical demodulator 45 such as SRQAM. A timing signal is detected by the timing circuit 767 from the demodulated signal, and the timing signal is sent to the time division unit 765. The demodulated signals D ₁ , D ₂ , and D ₃ are decompressed by the decompression unit 503 to be audio signals, sent to the speaker 65, and converted to audio.

Next, as shown in the block diagram of the base station in FIG. 116, three reception cells 768,
69, 770, base stations 771, 77 at the center of each
Reference numerals 2773 denote transceivers 761 a to 761 similar to those in FIG.
1j, and transmits and receives data of the same number of channels as the number of transceivers. The base station control unit 774 connected to each base station constantly monitors the traffic volume of communication of each base station, and allocates a channel frequency to each base station and adjusts the size of the reception cell of each base station accordingly. It controls the whole system such as control.

As shown in the traffic distribution diagram of the conventional system of FIG. 117, in the conventional digital communication system such as QPSK, the transmission capacity of Ach of the receiving cells 768 and 770 is the same as that of d = A. Usage efficiency 2bit /
The data 774d is obtained by combining the Hz data 774d and 774b and the data 774c in the diagram of d = B, and has a uniform frequency use efficiency of 2 bit / Hz at any point.
On the other hand, the actual urban areas are densely populated areas 775a, 775b, 77
Where the buildings are concentrated like 5c, the population density is high,
The communication traffic volume also shows a peak as shown in data 774e. There is little traffic in other surrounding areas.
In contrast to the data 774e of the actual traffic volume TF, the capacity of the conventional cellular telephone has the same frequency efficiency of 2 bits / Hz in all regions as shown by the data 774d. In other words, there is an inefficiency that the same frequency efficiency is applied to places where the traffic volume is small and places where the traffic volume is small. In the conventional method, in a region with a large traffic volume, the frequency allocation is increased to increase the number of channels, or the size of the receiving cell is reduced. However, increasing the number of channels has been restricted by the frequency spectrum. In addition, the transmission power has been increased by multi-leveling such as 16QAM and 64QAM in the conventional method. Decreasing the size of the reception cell and increasing the number of cells increases the number of base stations and increases the installation cost. There are the above problems.

Ideally, increasing the frequency efficiency in an area with a large amount of traffic, increasing the frequency efficiency in an area with a small amount of traffic, and decreasing the frequency efficiency in an area with a small amount of traffic increases the efficiency of the entire system. Can be The above can be realized by employing the hierarchical transmission system of the present invention. This will be described with reference to the communication capacity / traffic distribution diagram according to the eighth embodiment of the present invention shown in FIG. FIG.
8 are received cells 770B, 768, and 7 in order from the top.
The communication capacities on the lines AA ′ of 69, 770 and 770a are shown. Reception cells 768 and 770 use channel group A. Reception cells 770b, 769, and 770a use the frequency of channel group B that does not overlap with channel group A. These channels correspond to the traffic volume of each receiving cell as shown in FIG.
The number of channels is increased or decreased by 16 base station controllers 774. In FIG. 118, d = A indicates the distribution of the communication capacity of the A channel. d = B is the communication capacity of the B channel, d = A + B is the communication capacity of all channels, TF is the communication traffic amount, and P is the distribution of buildings and population. Since the receiving cells 768, 769, and 770 use the multilayer hierarchical transmission system such as SRQAM described in the previous embodiment, as shown in the data 776a, 776b, and 776c, the frequency utilization efficiency of QPSK is 3 bits / Hz. Doubled 6 bit / Hz can be obtained in the periphery of the base station. It decreases to 4 bit / Hz and 2 bit / Hz toward the periphery. If the transmission power is not increased, dotted lines 777a, b,
2 bits compared to the size of the QPSK reception cell shown in c.
/ Hz area is narrowed, but by slightly increasing the transmission power of the base station, an equivalent reception cell size can be obtained.
A slave station compatible with 64 SRQAM transmits and receives using a modified QPSK in which the shift amount of SRQAM is S = 1 at a location far from the base station, transmits and receives 16 SRQAM at a near location, and transmits and receives 64 SRQAM at a further location. Therefore, the maximum transmission power does not increase as compared with QPSK. In addition, the 4SRQ as shown in the block diagram of FIG.
AM transceivers can communicate with other phones while maintaining compatibility. The same applies to the case of 16 SRQAM shown in the block diagram of FIG. Therefore, there are slave units of three modulation systems. In the case of mobile phones, small weighability is important. 4 SRQ
In the case of AM, the frequency usage efficiency is reduced and the call charge is increased. However, since the circuit is simplified, it is suitable for users who need to reduce the size and weight. Thus, this method can be used for a wide range of applications.

As described above, a transmission system having different distributions of capacity such as d = A + B in FIG. 118 can be obtained.
By installing the base station in accordance with the traffic volume of the TF, there is a great effect that the overall frequency use efficiency is improved. In particular, in the microcell system with a small cell, many sub-base stations can be installed, so that the sub-base stations can be easily installed in a place with a lot of traffic, so that the effect of the present invention is high.

Next, the data arrangement of each time slot will be described with reference to the data time arrangement diagram of FIG. FIG.
FIG. 119A shows a conventional time slot, and FIG. 119B shows a time slot according to the eighth embodiment. As shown in FIG. 119 (a), in the conventional transmission / reception-based frequency system, the synchronization signal S is transmitted in the time slot 780a at the frequency A at the time of Down, that is, at the time of transmission from the base station to the slave station, and the slot 780b,
At 780c and 780d, transmission signals to the slave units of the A, B and C channels are sent. Next, when transmitting from the Up side, that is, the slave unit to the base station, the time slot 781a, 781
b, 781c, and 781d transmit synchronization signals, and transmit signals of channels a, b, and c, respectively.

In the case of the present invention, as shown in FIG. 119 (b), since the above-mentioned hierarchical transmission system such as 64 SRQAM is used, each of D ₁ , D ₂ , and D ₃ has two hierarchical data of 2 bits / Hz. With. Since the A ₁ and A ₂ data are transmitted by 16 SRQAM, the slots 782b and 782c and the slot 783 are used.
b, 783c, the data rate is about twice as high. It can be sent in half the time when sending with the same sound quality. Therefore, the time slots 782b and 782c are half the time.
In this way, twice the transmission capacity can be obtained in the area of the second hierarchy of 776c in FIG. 118, that is, in the vicinity of the base station. Similarly,
Time slot 782 g, transmission and reception of E ₁ data in 783g performed in 64SRQAM. Since it has approximately three times the transmission capacity, three times E ₁ , E ₂ , E _{3 in the} same time slot
3 channels can be secured. In this case, transmission / reception is required in an area near the base station. In this way, there is an effect that a maximum of about three times as many calls can be obtained in the same frequency band. However, in this case, the call is performed as it is in the vicinity of the base station, and is actually lower than this number. Also, the actual transmission efficiency drops to about 90%. In order to enhance the effects of the present invention, it is desirable that the distribution of the traffic area be consistent with the distribution of the transmission capacity according to the present invention. But,
As shown in the TF diagram of FIG. 118, in an actual city, a green belt is arranged around a building street. Even in the suburbs, fields and forests are located around residential areas. Therefore, the distribution is close to the distribution of TF. Therefore, the effect of applying the present invention is high.

In the TDMA time slot diagram shown in FIG. 120, (a) shows the conventional system and (b) shows the system of the present invention. FIG.
As shown in FIG. 20 (a), transmission to the slaves of the A and B channels is performed in time slots 786a and 786b in the same frequency band, and transmission from the slaves of the A and B channels respectively in time slots 787a and 787b. I do. FIG.
(B), the cases slot 788a of the case of the present invention 16SRQAM performs reception of A ₁ channel and performs transmission of A ₁ channel slot 788c. The time slot width becomes about 1/2. For 64SRQAM performs D ₁ channel reception slot 788I, for transmission of D ₁ channel slot 788L. The time slot width becomes about 1/3.

In order to reduce power consumption, the slot 78
16 SRQAM with 1/2 time slot in 8p
Performing a reception E _1, but transmission is carried out in the slot 788r in normal time slot 4SRQAM. 16 SRQAM
Since 4SRQAM consumes less power, it has the effect of reducing power consumption during transmission. However, the longer the occupation time, the higher the communication fee. The effect is high when the battery is small and lightweight, or when the remaining battery power is low.

As described above, since the transmission capacity distribution can be set according to the actual traffic distribution, there is an effect that the substantial transmission capacity can be increased. In addition, since the base station and the slave station can select the transmission capacity of three or two transmission capacities, the frequency efficiency can be reduced to reduce power consumption, or conversely, the efficiency can be reduced to reduce the call charge, and the degree of freedom is high, and various effects can be obtained. Is obtained. Also, 4SRQA with low transmission capacity
By using a method such as M, it is possible to set a slave unit whose circuit is simplified and whose size and cost are reduced. In this case, one of the features of the present invention is that transmission compatibility between all models can be obtained as described in the previous embodiment. In this way, with the increase in transmission capacity, a wide range of models from microminiature machines to high-performance machines can be developed.

(Embodiment 9) A ninth embodiment will be described below with reference to the drawings. Embodiment 9 is an embodiment in which the present invention is applied to an OFDM transmission system. A block diagram of the OFDM transceiver in FIG. 123 and an operation principle diagram of the OFDM in FIG. 124 are shown. F
OFDM, which is a type of DM, has higher frequency band use efficiency than general FDM by making adjacent carriers orthogonal. In addition, it has been studied for digital music broadcasting and digital TV broadcasting because of its resistance to multipath interference such as ghosts. As shown in the principle diagram of OFDM in FIG.
In the case of, the input signal is
3 are arranged at 1 / ts intervals to create sub-channels 794a to 794e. This signal is converted to an inverse FFT signal 40
, And performs inverse FFT transform on the time axis 799 to generate a transmission signal 795. During the period of the effective symbol period 796 of ts, the inverse FFT signal is transmitted, and a guard period 797 of tg is provided between each symbol.

The operation of the ninth embodiment when transmitting and receiving HDTV signals will be described with reference to the block diagram of the OFDM-CCDM hybrid system shown in FIG. HDTV input
Signal low band D _1-1 and the image encoder 401 (midrange - low frequency) D _1-2 and separated into (high band - - midrange low range) image signal of the hierarchical structure of three layers of D _2, It is input to the input unit 742. In the first data string input unit 743, the _D1-1 signal is C
is higher ECC encoded with ode gain, D _1-2 signal is the encoding of normal code gain ECC. _D1-1 and D
_2-2 is time-division multiplexed by the TDM unit 743, and D ₁
Producing a signal, the modulator 852a D ₁ serial to parallel converter 79
1a. D ₁ signal consists of n parallel data, C-CDM modulator 4a of n months, is input to the first input of 4b · · ·.

On the other hand, the D of the high frequency component signal_TwoIs the input unit 742
ECC unit 744a in the second data string input unit 744
ECC (Error Correction Code)
Trellis-encoded in trellis encoder 744b
And the D of the modulator 852a_TwoInput to the serial / parallel unit 791b.
The data becomes n parallel data, and the C-CDM modulators 4a,
4b are input to the second input unit. D of the first input unit₁De
Data and D of the second input unit _TwoEach C-CDM by data
The modulators 4a, 4b, 4c,...
Is subjected to C-CDM modulation. These n C-CDM modulators
Have carriers at each different frequency and are adjacent
The carriers 794a, 794b and 794c in FIG.
.. Are orthogonal on the frequency axis 793 as shown in FIG.
You. In this way, n modulated signals that are C-CDM modulated
Is the frequency axis dimension by the inverse FFT circuit 40.
From 793 to the time axis dimension 790,
Time signal 796a, 796b, etc. with an effective symbol length of ts
become. Between the effective symbol time zones 796a and 796b
Is a guard time zone of Tg seconds 7 to reduce multipath interference.
97a is provided. This is time axis and signal level
The representation is the time axis-signal level diagram of FIG.
Tg of guard time zone 797a is affected by multipath
From time to time, it is determined according to the application. TV ghost etc.
By setting Tg longer than the influence time of
When transmitting, the modulated signal from the inverse FFT circuit 40 is
The signal is converted to one signal by the transmitter 40b by the barter 40b.
And transmitted as an RF signal.

Next, the operation of the receiver 43 will be described. FIG.
4 is shown in FIG. The received signal is input to the input unit 24 in FIG. 123, input to the modulation unit 852b, digitized, expanded into Fourier coefficients by the FFT unit 40a, and time-axis 799 as shown in FIG.
Is mapped to the frequency axis 793a. From the time axis symbol signal of FIG. 124, the carrier 794 of the frequency axis signal
a, 794b, etc. Since these carriers are orthogonal to each other, each modulated signal can be separated. The 16 SRQAM and the like shown in FIG. 125 (b) are demodulated and sent to the respective C-CDM demodulators 45a and 45b. Then, each C-CDM demodulator 45 of the C-CDM demodulator 45
5a, b, etc., the sub-signals of D ₁ and D ₂ are demodulated hierarchically, and the D ₁ parallel serial converter 852a and the D ₂ parallel serial converter 852b convert the original D ₁ and D ₂ signals into serial signals. Demodulated. In this case, FIG.
Since the hierarchical transmission method using the C-CDM as shown in FIG. 5 (b) is used, D _{1 under the} reception condition with a poor C / N value.
Signal only is demodulated, in good receiving condition, both D ₁ and D2 signal is demodulated. The demodulated D ₁ signal is output to an output unit 75.
7 demodulated. Because of the high code cane D _1-1 signal error correction as compared with D _1-2 signal, an error signal of the D _1-1 signal is reproduced even in bad conditions with more reception condition. D _1-
1 signal is output to the LDTV by the 1-1 image decoder 402c.
Becomes a low frequency signal, D _1-2 signal becomes a signal of the middle frequency component of the EDTV by a 1-2 video decoder 402d, and output.

The D ₂ signal is trellis-decoded and output as a high-frequency component of HDTV by the second image decoder 402b. LDTV is output only with the above low frequency signal,
By adding the above-mentioned middle band component, an EDTV signal of a wide NTSC grade is outputted, and by further adding the above-mentioned high band component, an HDTV signal is synthesized. As in the previous embodiment, a TV signal having an image quality corresponding to the reception C / N can be received. In the case of the ninth embodiment, by using OFDM and C-CDM in combination, it is possible to realize hierarchical transmission that cannot be realized by OFDM itself. As shown in the error rate C / N of FIG. 130, the curve 805 of the conventional OFDM-TCM modulation signal is compared with the C-CDM-OFD of the present invention.
In the M method, the error rate of the sub-channel 1 807a decreases and the error rate of the sub-channel 2 807b increases. Thus, a hierarchical type is realized.

OFDM is robust against multipaths such as TV ghosts because it contains multipath interference signals during the guard period Tg. Therefore, it can be used for digital TV broadcasting for an automobile TV receiver. However, since the transmission is not a hierarchical transmission, it cannot be received below a certain C / N threshold. By combining with the C-CDM of the present invention, two types of image reception (Graditional Degradation) that are resistant to multipath and correspond to C / N deterioration can be realized. When receiving TV in a car, not only the multipath but also the C / N value deteriorates. Therefore, the service area of the TV broadcasting station does not widen so much only by the multipath measures. However, by combining with the C-CDM of the hierarchical transmission, even if the C / N is considerably deteriorated, it is possible to receive in the LDTV grade. On the other hand, in the case of an automobile TV, since the screen size is usually 100 dimensions or less, sufficient image quality can be obtained with the LDTV grade. There is an effect that the service area of the LDTV grade of the automobile TV is greatly expanded.
If OFDM is used for the entire HDTV band, the DSP circuit scale increases in the current semiconductor technology. So low frequency TV
A method of transmitting only the signal _D1-1 by OFDM will be described. FIG.
As shown in the block diagram of 8, two D _1-2 and D ₂ signal of the middle band component and the high frequency component of HDTV and C-CDM multiplexing of the present invention, it is transmitted in frequency band A by FDM40D. On the other hand, the signal received by the receiver is frequency-separated by the FDM 4oe, demodulated by the C-CDM demodulator 4b of the present invention,
In the same manner as in FIG. 123, the middle frequency component and the high frequency component of the HDTV are reproduced. The operation of the image decoder in this case is the same as in the first, second, and third embodiments, and will not be described.

[0348] Then D _1-1 signal is a low frequency signal of MPEG1 grade HDTV is in the OFDM converter 852C becomes parallel signals by the serial-parallel converter 791 QP
After receiving SK or 16QAM modulation, the signal is converted into a signal on the time axis by the inverse FFT unit 40 and the frequency band B is converted by the FDM 40d.
Sent by

On the other hand, the signal received by receiver 43 is FD
The frequency is separated in the M unit 40e, and the OFDM demodulation unit 8
Becomes a signal of a number of frequency axis by FFT40a at 52 d, each of demodulators 45a, demodulated by 45b, etc., parallel to serial converter 852a by D _1-1 signal is demodulated, as in Figure 123, the LDTV grade D
_{The 1-1} signal is output from the receiver 43.

[0350] Thus, hierarchical transmission in which only the LDTV signal is subjected to OFDM is realized. By using the method of FIG. 138, the complex circuit of OFDM needs only the LDTV signal. The LDTV signal has a 1/20 bit rate compared to the HDTV signal. Therefore, the circuit scale of OFDM is 1/2.
0, and the overall circuit scale is greatly reduced.

OFDM is a transmission method that is resistant to multipath, and is mainly applied to mobile stations, such as when receiving a portable TV or a car TV or when receiving a digital music broadcast from a car, where multipath interference is large and fluctuates. I am trying to do. In such applications, a small screen size of 10 inches or less of 4 inches to 8 inches is mainly used. Therefore, the method of OFDM-modulating all high-resolution TV signals such as HDTV and EDTV is ineffective for the cost involved, and it is sufficient to receive an LDTV Great II TV signal for an automobile TV. On the other hand, in a fixed station such as a home TV, since the multipath is always constant, it is easy to take measures against the multipath. For this reason, OFD except for strong ghost areas
The effect of M is not high. OFDM for middle and high frequency components of HDTV
Is not advisable in the current situation where the circuit scale of OFDM is large. Accordingly, the method of using OFDM shown in FIG. 138 of the present invention only for low-frequency TV signals does not lose the effect of OFDM that greatly reduces the multipath interference of LDTV received in a mobile station such as an automobile. , OFDM
Has a great effect that the circuit scale can be greatly reduced to 1/10 or less.

[0352] Incidentally, OFDM only D _1-1 in Fig. 138
Modulation to have can be OFDM modulating the D _1-1 and D _1-2. In this case, since D _1-1 and D _1-2 is capable of 2 hierarchical transmission of C-CDM, hierarchical broadcasting is realized strong multi-pulse even in a mobile such as an automobile, in the mobile, L
Gradient Degradation that DTV and SDTV can receive images of image quality according to the reception level and antenna sensitivity
The effect of n is born.

Thus, the hierarchical transmission of the present invention becomes possible,
Various effects described above can be obtained. In the case of OFDM, which is particularly resistant to multipath, by combining with the hierarchical transmission of the present invention, it is possible to obtain an effect that it is resistant to multipath and the data transmission grade can be deteriorated in accordance with the deterioration of the reception level.

As a method of realizing the hierarchical transmission system, as shown in FIG. 126 (a), each subchannel 794a-c of the FDM is a first layer 801a and subchannels 794d-f are a second layer 801b. By providing a frequency guard band 802a of fg in the middle and providing a power difference 802b of Pg as shown in FIG. 126 (b), the transmission power of the first layer 801a and the second layer 801b can be differentiated.

By utilizing this, the previously described FIG.
As shown in (d), the power of the first layer 801a can be increased within a range that does not interfere with analog TV broadcasting. In this case, as shown in FIG. 108 (e), the threshold value of the receivable C / N value of the first layer 801a is lower than that of the second layer 801b. Therefore, there is an effect that the reception of the first layer 801a becomes possible even in an area with a low signal level or an area with a lot of noise. As shown in FIG. 147, two-layer hierarchical transmission is realized. This is called the Power-Weighted-OFDM method
(PW-OFDM) is referred to in the text. By combining the P-OFDM of this embodiment with the above-described C-CDM scheme of the present invention, the number of hierarchies is increased to three as shown in FIG. .

As a specific circuit, as shown in FIG. 144, the first layer data is inverted FFT by carriers f _{1 to} f ₃ by modulators 4a to 4c having a large amplitude via first data string circuit 791a.
40, and the second layer data is passed through a second data string circuit 791b to modulators 4d to 4f having normal amplitudes.
OFDM modulation is performed by the inverse FFT 40 on the carriers f _{6 to} f ₈ and transmitted.

The received signal is separated into signals having carriers f _{1 to} f _n by FFT 40 a of receiver 43, and carriers f _{1 to} f ₃ are converted into first data stream D by demodulators 45 a to 45 c.
_1, that is, the first layer 801a is demodulated and the carriers f _{6 to} f ₈
The second data stream D _2, i.e. the second layer 801b is demodulated from.

Since the power of the first layer 801a is large, it can be received even in an area where the signal is weak. Thus, two-layer hierarchical transmission is realized by PW-OFDM. PW-OFDM to C-CD
When combined with M, three or four layers are realized. The other operations in FIG. 144 are the same as those in the case of the block diagram in FIG. 123, and thus description thereof is omitted.

Next, the Time-Weighted-OFDM of the present invention will be described.
The layering method of the (TW-OFDM) method is described. OFDM
As described above, since the system has the guard time zone tg, the ghost, that is, the delay time t _{M of the} multipath signal is t _M.
If the conditional expression <tg is satisfied, the influence of ghost can be eliminated. In a fixed station such as an ordinary household TV receiver, t
_M is as small as several μs and is constant, so that it is easy to cancel. However, in the case of a mobile station such as an in-vehicle TV receiver, since there are many reflected waves, t _M is not only large and close to several tens of μs, but also changes with the movement, so that it is difficult to cancel. Therefore, it is expected that hierarchies for multipaths will be required.

The method of hierarchization of this embodiment will be described.
As shown at 46, by making the guard time tga of the A-layer longer than the guard time tgb of the B-layer, the symbol of the sub-channel of the A-layer becomes stronger against ghost. In this way, hierarchical transmission for multipath is realized by weighting of the guard time. This method is called Guard-Time
-Called Weighted-OFDM (GTW-OFDM).

Further, the symbol time Ts of the A-th layer and the B-th layer
Are set to the same number, the symbol time tsa of A is set to be longer than the symbol time tsb of B. As a result, if the intervals of the carriers A and B on the frequency axis are △ fa and △ fb, respectively, △ fa <△ fb
It is. For this reason, the error rate when the symbol of A is demodulated is lower than that of the symbol of B. In this way, by layering the weighting of the symbol time Ts, two layers are realized for the multipath of the Ath layer and the Bth layer.
Carrier-Spacing-Weighted-OFDM (CSW-OFDM)
Call. GTW-0FDM realizes two-layer transmission, and transmits a low-resolution TV signal in layer A and a high-frequency component in layer B, so that there are many ghosts like in-vehicle TV receivers. Stable reception of a low-resolution TV is possible even under reception of conditions. Further, by differentiating the symbol time ts using CSW-OFDM, the layering of the C / N of the layer A and the layer B is performed by the GTW-OFDM.
By combining with OFDM, a great effect that more stable reception can be achieved in an in-vehicle TV having a low reception signal level is realized. High resolution is not required for in-vehicle and portable TVs. Since the time ratio of the symbol time including the low-resolution TV signal is small, increasing the guard time alone does not significantly reduce the overall transmission efficiency. Therefore, using the GTW-OFDM of this embodiment, a low resolution T
Hierarchical type in which mobile stations such as portable TVs and in-vehicle TVs and fixed stations such as home TVs are compatible with little effect on transmission efficiency by taking multipath measures with emphasis on V signals There is a great effect of realizing TV broadcasting. In this case, as described above, by combining with CSW-OFDM or C-CDM, the layering of C / N is added, and more stable mobile station reception becomes possible.

The effect of multipath will be specifically described.
As shown in FIG. 145 (a), in the case of multipaths 810a to 810d having a short delay time, the first transmission and the second layer signals can be received, and the HDTV signal can be demodulated. However, FIG.
In the case of long multipaths 811a to 811d as shown in (b), demodulation cannot be performed because the guard time and Tgb of the B signal of the second layer are short. In this case, the A signal of the first layer has a long guard time Tga, and is not affected by a multipath having a long delay time. As described above, the B signal contains the high-frequency component of the TV, and the A signal contains the low-frequency component of the TV. For example, an in-vehicle TV can reproduce an LDTV.
Further, since the symbol time Tsa of the first layer is set to be longer than Tsb, the first layer is also strong against deterioration of C / N.

By differentiating the guard time and the symbol time in this manner, a two-dimensional hierarchy of OFDM can be realized with a simple configuration. By combining guard time differentiation and C-CDM in a configuration as shown in FIG. 123, it is possible to achieve both hierarchies of multipath and C / N value deterioration.

Here, a detailed description will be given using a specific example.
The multipath delay time T _M is as D / U ratio is small, the number of reflected waves from the direct wave increases. For example, FIG.
As shown in the figure, when D / U <30 dB, the influence of the reflected wave becomes large and becomes 30 μs or more. As shown in FIG.
By taking Tg of μs or more, reception is possible even under the worst conditions. Therefore, as specifically shown in FIG. 149 (a), the 2 ms shown in FIG.
Of the symbols in the first layer 801a and the second layer 8
FIG. 149 (c) shows a group of three layers, ie, 01b and a third layer 801c. Guard time 797a, 797b, 797c of each group, ie, Tga, Tg
By setting the weights b and Tgc to, for example, 50 μs, 5 μs, and 1 μs, a hierarchical broadcast related to a multipath of three layers 801a, 801b, and 801c as shown in FIG. 150 is realized. When GTW-OFDM is applied to all image qualities, transmission efficiency naturally drops. However, by taking the GTW-OFDM multipath measure only for the image quality signal of the LDTV having a small amount of information, there is an effect that the overall transmission efficiency does not decrease much. In particular, in the first layer 801a, the guard time Tg is set to 5
Since the time is set to 0 μs, it can be received even by a vehicle-mounted TV receiver. The circuit shown in the block diagram of FIG. 127 is used. In particular, since a TV mounted on a vehicle can have an image quality of LDTV grade, a transmission capacity of about 1 Mbps of the MPEG1 class is sufficient. Therefore, as shown in FIG.
If aTsa is 200 μs for a period of 2 ms, 2M
bps, which is good. Further, even if the symbol rate is reduced by half, the symbol rate becomes close to 1 Mbps, and image quality of LDTV grade can be obtained. In particular, when the C-CDM of the present invention is combined with GTW-OFDM, the effect is further enhanced because the transmission efficiency does not decrease. FIG.
In 49, the symbol time is 796 for the same number of symbols.
a, 796b, 796c are 200 μs, 150 μs, 1
It is differentiated to 00 μs. Accordingly, hierarchical transmission is performed in which the error rate increases in the order of the first layer, the second layer, and the third layer.

At the same time, hierarchical transmission is realized for C / N. As shown in FIG. 151, CSW-OFDM and CSW
-Two-dimensional hierarchical transmission of multipath and C / N is realized by the combination of OFDM. As described above, CSW-
The present invention can also be realized by combining OFDM and the C-CDM of the present invention, and in this case, there is an effect that a decrease in the overall transmission efficiency is small. In the first layer 801a, the first-second layer 851a, and the first-third layer 851a, the multipath T _M is large and C /
LDTV grade stable reception is possible even in applications where N is low, for example, in-vehicle TV receivers. The second layer 801b and the 2-3rd layer 851b have a low C / N like a fringe area of a service area, and can receive a standard resolution SDTV grade at a fixed station in a reception area where there are many ghosts. In the third layer 801c occupying more than half of the service area, the C / N is high, the direct wave is large, and there are few ghosts, so that the image can be received with HDTV grade image quality.
In this way, two-dimensional hierarchical broadcasting of C / N and multipath is realized. Such a great effect is achieved by the GTW-OF of the present invention.
Combination of DM and C-CDM or GTW-OFD
It is obtained by a combination of M and CSW-C-CDM.
Conventionally, a hierarchical broadcasting system for C / N has been proposed, but the present invention realizes a two-dimensional matrix hierarchical broadcasting of C / N and multipath.

Specific HDTV, SDTV, LDTV of two-dimensional hierarchical broadcasting of three layers of C / N and three layers of multipath
FIG. 152 shows a time allocation diagram of the TV signal of the three layers. As shown in the figure, an LDTV is arranged in the first layer slot 796a1 of the A layer that is strong against the first multipath, and then the slot 796a2 that is strong against multipath and the slot 796b1 that is strong against C / N deterioration.
Important HP such as SDTV synchronization signal and address signal
Arrange the signals. In the second and third layers of the B layer, general SDTV signals, that is, LP signals and HDTV HP signals are arranged. SDTV, EDTV, HD on layer 1, layer 2 and layer 3
A high-frequency component TV signal such as a TV is arranged.

In this case, the transmission rate decreases as the degree of resistance to CN deterioration or multipath increases, so that the resolution of the TV signal decreases. As shown in FIG.
An unprecedented effect of realizing lDegradation is obtained by the present invention. FIG. 153 expresses a three-dimensional hierarchical broadcasting of the present invention by using three parameters of CNR, multipath delay time, and transmission rate.

An embodiment will be described using an example in which a two-dimensional hierarchical structure can be obtained by a combination of the GTW-OFDM of the present invention and the above-described C-CDM of the present invention or a combination of the GTW-OFDM and the CSW-C-CDM. But GTW-O
Even when a combination of FDM and Power-Weighted-OFDM or a combination of GTW-OFDM and another CNR hierarchical transmission system is used, two-dimensional hierarchical broadcasting is realized.

FIG. 154 shows carriers 794a, 794c,
The power of 794e is transferred to carriers 794b, 794d, 794.
This is transmitted with weighting smaller than f and realizes two-layered Power-Weighted-OFDM. Carriers 795 a, 7 orthogonal to carrier 794 a
Similarly, the electric power of the carrier 955c and the carriers 795b and 795d
, Two layers are obtained by weighting the power. When combined, a four-layer hierarchy is obtained, but FIG. 154 shows an embodiment in the case of two layers. As shown in the drawing, the frequency distribution of the carriers is dispersed, so that interference with other analog broadcasting and the like in the same frequency band is dispersed, so that the effect is reduced.

As shown in FIG. 155, one symbol 7
96a, 796b, 796c, the guard time 797a,
By adopting a time arrangement in which the time widths of 797b and 797c are changed, hierarchical multi-level transmission for three-layer multipath is realized. When the time arrangement shown in FIG.
The data of the layer and the layer C are dispersed on the time axis. Therefore, even if burst noise occurs at a specific time, by interleaving the data of each layer, the data is prevented from being destroyed, and the TV signal can be demodulated stably. In particular, by dispersing and interleaving the data of the layer A, it is possible to greatly reduce the interference of burst noise generated from the ignition device of another vehicle, which is generated at the time of receiving the vehicle-mounted TV.

In this case, a specific ECC encoder 7
44j and the block diagram of the ECC decoder 749j are shown in FIG.
60 (a) and 60 (b) respectively. In addition, FIG.
FIG. 27 shows a block diagram of an interleaving section 936b. De-interleave RAM 9 of de-interleave section 936b
Interleave table 954 processed in 36a
168 is shown in FIG. 168 (a), and the interleave distance L1 is shown in FIG. 168 (b).

By interleaving the data in this way, the disturbance of the burst noise can be reduced.
The block diagram of the VSB receiver in FIG. 161 and the VS in FIG.
As shown in the block diagram of the B transmitter, by using the transmitter for the 4VSB, 8VSB, or 16VSB described in the fourth, fifth, or sixth embodiment or the QAM or PSK transmission device described in the first or second embodiment, the burst can be obtained. Since interference of noise can be reduced, there is an effect that TV reception with less noise can be performed in terrestrial broadcasting.

By performing the three-layer broadcasting by the method shown in FIG. 155, the layer A can reduce the disturbance of the burst noise in addition to the multipath and the C / N deterioration described above.
This has the effect of stabilizing reception of LDTV grade TV by mobile stations such as receivers and pocket TVs.

The present invention relates to ASK, QAM, PSK, OFD
Although the embodiment has been described using the M modulation scheme, similar effects can be obtained with other modulation schemes. Also, by using the partial response, the error rate can be reduced not only in the recording system but also in the transmission system.

One feature of the multilevel transmission system of the present invention is to improve the frequency use efficiency, but for some receivers the power use efficiency is considerably reduced. Therefore, it cannot be applied to all transmission systems. For example, in the case of a satellite communication system between specific receivers, the most economical method is to replace the equipment with the highest frequency use efficiency and highest power use efficiency obtained at that time. In such a case, it is not always necessary to use the present invention.

However, in the case of a satellite broadcasting system or a terrestrial broadcasting system, a hierarchical transmission system as in the present invention is required. This is because satellite broadcasting standards require persistence of 50 years or more. During this period, the broadcasting standard is not changed, but the transmission power of the satellite is dramatically improved with technological innovation. Broadcasting stations must provide compatible broadcasting so that manufactured receivers can receive and view TV programs in the future several decades from now. Using the present invention, the existing NTS
The effects of compatibility between C broadcast and HDTV broadcast and expandability of future information transmission amount can be obtained.

Although the present invention places importance on frequency efficiency rather than power efficiency, transmission is achieved by setting several types of receivers each having a designed reception sensitivity according to each transmission stage on the receiver side. There is no need to increase the power of the machine so much.
For this reason, even a satellite with a small current power can transmit sufficiently. Further, even if the transmission power increases in the future, transmission can be performed according to the same standard, so that future expandability and compatibility between new and old receivers can be obtained. As described above, the present invention has a remarkable effect when used in the satellite broadcasting standard.

When the multi-level transmission system of the present invention is used for terrestrial broadcasting, the present invention is easier to implement than satellite broadcasting because there is no need to consider power use efficiency at all. As described above, the conventional digital HDTV broadcasting system has a remarkable effect of greatly reducing the unreceivable area in the service area and the effect of compatibility between the NTSC and the HDTV receiver or the receiver. Also, there is an effect that the service area as viewed from the sponsor of the TV program is substantially expanded. In the embodiment, QPSK, 16QAM, 32
Although the description has been made using the example using QAM and the modulation method of 4VSB, 8VSB, and 16VSB, 64QAM, 128QA
Needless to say, the present invention can be applied to M, 256QAM, 32VSB, 64VSB and the like. It goes without saying that the present invention can be applied to multi-valued PSK, ASK, and FSK as described with reference to the drawings. Although the embodiment in which the present invention is combined with TDM for transmission has been described, transmission may also be performed by combining FDM, CDMA and spread communication systems.

One feature of the multilevel transmission system of the present invention is to improve the frequency use efficiency, but for some receivers the power use efficiency is considerably reduced. Therefore, it cannot be applied to all transmission systems. For example, in the case of a satellite communication system between specific receivers, the most economical method is to replace the equipment with the highest frequency use efficiency and highest power use efficiency obtained at that time. In such a case, it is not always necessary to use the present invention.

However, in the case of a satellite broadcasting system or a terrestrial broadcasting system, a multilevel transmission system as in the present invention is required. This is because satellite broadcasting standards require persistence of 50 years or more. During this period, the broadcasting standard is not changed, but the transmission power of the satellite is dramatically improved with technological innovation. Broadcasting stations must provide compatible broadcasting so that manufactured receivers can receive and view TV programs in the future several decades from now. Using the present invention, the existing NTSC
The effects of compatibility between broadcasting and HDTV broadcasting and expandability of future information transmission amount can be obtained.

Although the present invention places importance on frequency efficiency rather than power efficiency, transmission is performed by setting several types of receivers each having a designed reception sensitivity according to each transmission stage on the receiver side. There is no need to increase the power of the machine so much.
For this reason, even a satellite with a small current power can transmit sufficiently. Further, even if the transmission power increases in the future, transmission can be performed according to the same standard, so that future expandability and compatibility between new and old receivers can be obtained. As described above, the present invention has a remarkable effect when used in the satellite broadcasting standard.

When the multilevel transmission system of the present invention is used for terrestrial broadcasting, the present invention is easier to implement than satellite broadcasting because there is no need to consider power use efficiency at all. As described above, the conventional digital HDTV broadcasting system has a remarkable effect of greatly reducing the unreceivable area in the service area and the effect of compatibility between the NTSC and the HDTV receiver or the receiver. Also, there is an effect that the service area as viewed from the sponsor of the TV program is substantially expanded. Although the embodiment has been described using an example using the modulation schemes of 16 QAM and 32 QAM, 64 QAM and 1 QAM are used.
It goes without saying that the present invention can be applied to 28QAM, 256QAM, and the like. Also, as described with reference to FIG.
Needless to say, it can be applied to K, ASK, and FSK.

[0383]

As described above, the present invention provides a signal input unit,
A transmission device for performing data transmission, comprising: a modulation unit that modulates a plurality of carriers having different phases with an input signal from the input unit to generate an m-valued signal point on a signal vector diagram, and a transmission unit that transmits the modulated signal. In step (1), a first data string and a second data string of n values are input, the signal is divided into n signal point groups, and the signal point groups are assigned to data of the first data strings, respectively. Allocating each data of the second data group to each signal point in, transmitting a signal by a transmitting transmitter,
The signal point is divided into n-valued signal points in a receiving device having an input portion of the transmission signal, a demodulator for demodulating a QAM modulated wave of a p-valued signal point on a signal space diagram, and an output portion. The first data string of the signal point group n value is correlated and demodulated, and the data of the second data string of the p / n value is demodulated and reproduced at the signal point of substantially the p / n value in the signal point group and received. By transmitting data using the device, for example, the modulator 4 of the transmitter 1 divides the n-valued first data string, the second data string, and the third data string into signal point groups and modifies the data. QA of value
The first receiver 23 transmits an M-modulated signal, and a demodulator 25
The first data string of the n value is calculated by the
The data sequence and the second data sequence are demodulated by the third receiver 43 into the first data sequence, the second data sequence, and the third data sequence. Even if the receiver has only the demodulation capability of n <m, where n <m, a transmission device capable of demodulating n-value data and having compatibility and development can be obtained. Further, when the distance between the signal point closest to the origin and the I-axis or the Q-axis among the signal points of the QAM method is f, the signal point is shifted so that the distance becomes nf such that n> 1. , Hierarchical transmission becomes possible.

By transmitting the NTSC signal to the transmission system as the first data sequence and the difference signal between HDTV and NTSC as the second data sequence, the satellite broadcasting is compatible with the NTSC broadcasting and the HDTV broadcasting. Digital broadcasting with a high scalability can be achieved, and terrestrial broadcasting has a remarkable effect of expanding a service area and eliminating an unreceivable area.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an entire system of a transmission device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a transmitter 1 according to the first embodiment of the present invention.

FIG. 3 is a vector diagram of a transmission signal according to the first embodiment of the present invention.

FIG. 4 is a vector diagram of a transmission signal according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating assignment of codes to signal points according to the first embodiment of the present invention.

FIG. 6 is a coding diagram for a signal point cloud according to the first embodiment of the present invention.

FIG. 7 is a coding diagram for signal points in a signal point group according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating coding of signal points and signal points according to the first embodiment of the present invention.

FIG. 9 is a threshold state diagram of a signal point group of a transmission signal according to the first embodiment of the present invention.

FIG. 10 is a vector diagram of modified 16-value QAM according to the first embodiment of the present invention.

FIG. 11 is a diagram illustrating a relationship between an antenna radius r ₂ and a transmission power ratio n according to the first embodiment of the present invention.

FIG. 12 is a diagram of signal points of modified 64-value QAM according to the first embodiment of the present invention.

FIG. 13 is a diagram illustrating a relationship between an antenna radius r ₃ and a transmission power ratio n according to the first embodiment of the present invention.

FIG. 14 is a vector diagram of a signal group of modified 64-QAM and a group of sub-signal points according to the first embodiment of the present invention;

FIG. 15 is an explanatory diagram of ratios A ₁ and A ₂ of modified 64-value QAM according to the first embodiment of the present invention.

FIG. 16 is a relationship diagram between antenna radii r ₂ and r ₃ and transmission power ratios n ₁₆ and n _{64 according to} the first embodiment of the present invention.

FIG. 17 is a block diagram of a digital transmitter according to the first embodiment of the present invention.

FIG. 18 is a signal space diagram diagram of 4PSK modulation according to the first embodiment of the present invention.

FIG. 19 is a block diagram of a first receiver according to the first embodiment of the present invention.

FIG. 20 is a signal space diagram diagram of a 4PSK modulated signal according to the first embodiment of the present invention.

FIG. 21 is a block diagram of a second receiver according to the first embodiment of the present invention.

FIG. 22 is a signal vector diagram of modified 16-value QAM according to the first embodiment of the present invention.

FIG. 23 is a signal vector diagram of modified 64-value QAM according to the first embodiment of the present invention.

FIG. 24 is a flowchart according to the first embodiment of the present invention.

25A is a signal vector diagram of 8-level QAM according to the first embodiment of the present invention. FIG. 25B is a signal vector diagram of 16-level QAM according to the first embodiment of the present invention.

FIG. 26 is a block diagram of a third receiver according to the first embodiment of the present invention.

FIG. 27 is a diagram of signal points of modified 64-value QAM according to the first embodiment of the present invention.

FIG. 28 is a flowchart according to the first embodiment of the present invention.

FIG. 29 is an overall configuration diagram of a transmission system according to a third embodiment of the present invention.

FIG. 30 is a block diagram of a first image encoder according to Embodiment 3 of the present invention.

FIG. 31 is a block diagram of a first image decoder according to a third embodiment of the present invention;

FIG. 32 is a block diagram of a second image decoder according to Embodiment 3 of the present invention.

FIG. 33 is a block diagram of a third image decoder according to the third embodiment of the present invention.

FIG. 34 is an explanatory diagram of time multiplexing of D ₁ , D ₂ , and D ₃ signals according to the _third embodiment of the present invention.

FIG. 35 is an explanatory diagram of time multiplexing of D ₁ , D ₂ , and D ₃ signals according to the _third embodiment of the present invention.

FIG. 36 is an explanatory diagram of time multiplexing of D ₁ , D ₂ , and D ₃ signals according to the _third embodiment of the present invention.

FIG. 37 is a configuration diagram of an entire system of a transmission device according to a fourth embodiment of the present invention.

FIG. 38 is a vector diagram of signal points of modified 16QAM in Embodiment 3 of the present invention.

FIG. 39 is a vector diagram of signal points of modified 16QAM in Embodiment 3 of the present invention.

FIG. 40 is a vector diagram of signal points of modified 64QAM in Embodiment 3 of the present invention.

FIG. 41 is a signal arrangement diagram on a time axis according to the third embodiment of the present invention.

FIG. 42 is a signal arrangement diagram on the time axis of the TDMA system according to the third embodiment of the present invention.

FIG. 43 is a block diagram of a carrier recovery circuit according to a third embodiment of the present invention;

FIG. 44 is a view showing the principle of carrier recovery according to the third embodiment of the present invention;

FIG. 45 is a block diagram of an inverse modulation type carrier recovery circuit according to a third embodiment of the present invention.

FIG. 46 is a signal point arrangement diagram of a 16QAM signal according to the third embodiment of the present invention.

FIG. 47 is a signal point arrangement diagram of a 64QAM signal according to the third embodiment of the present invention.

FIG. 48 is a block diagram of a 16-multiplier carrier recovery circuit according to a third embodiment of the present invention;

FIG. 49 shows D _V1 , D _H1 , D _V2 , and D _V1 of Embodiment 3 of the present invention.
Illustration of time multiplexing of D _H2 , D _V3 , and D _H3 signals

FIG. 50 shows D _V1 , D _H1 , D _V2 , and D _V1 of Embodiment 3 of the present invention.
Explanatory diagram of TDMA time multiplexing of D _H2 , D _V3 , and D _H3 signals

FIG. 51 shows D _V1 , D _H1 , D _V2 , and D _V1 of Embodiment 3 of the present invention.
Explanatory diagram of TDMA time multiplexing of D _H2 , D _V3 , and D _H3 signals

FIG. 52 is a diagram showing a reception interference area of the conventional system in the fourth embodiment of the present invention.

FIG. 53 is a diagram of a reception obstruction area in the case of a hierarchical broadcasting system according to the fourth embodiment of the present invention.

FIG. 54 is a diagram showing a reception interference area of the conventional system in the fourth embodiment of the present invention.

FIG. 55 is a diagram of a reception obstruction area in the case of a hierarchical broadcasting system according to the fourth embodiment of the present invention.

FIG. 56 is a digital broadcast station 2 according to the fourth embodiment of the present invention.
Station jamming area diagram

FIG. 57 is a signal point arrangement diagram of a modified 4ASK signal according to the fifth embodiment of the present invention.

FIG. 58 is a signal point arrangement diagram of modified 4ASK in the fifth embodiment of the present invention.

FIG. 59 (a) is a variation 4A in the fifth embodiment of the present invention.
SK signal point arrangement diagram (b) is a signal point arrangement diagram of modified 4ASK in the fifth embodiment of the present invention.

FIG. 60 is a signal point arrangement diagram of a modified 4ASK signal in the case of a low C / N value in the fifth embodiment of the present invention.

FIG. 61 shows a 4VSB, 8VSB transmitter according to the fifth embodiment.

FIG. 62 (a) is a spectrum diagram of an ASK signal, that is, a filtered multi-level VSB signal according to the fifth embodiment of the present invention, and FIG. 62 (b) is a frequency distribution diagram of the VSB signal according to the fifth embodiment of the present invention.

FIG. 63 shows 4VSB, 8VSB, and 16 in Example 5.
Block diagram of VSB Receiver

FIG. 64 is a block diagram of a video signal transmitter according to a fifth embodiment of the present invention.

FIG. 65 is a block diagram of an entire TV receiver according to a fifth embodiment of the present invention.

FIG. 66 is a block diagram of another TV receiver according to the fifth embodiment of the present invention.

FIG. 67 is a block diagram of a satellite / terrestrial TV receiver according to a fifth embodiment of the present invention.

FIG. 68 (a) shows C of 8VSB in Examples 5 and 6.
(b) Constellation of 8VSB in Examples 5 and 6
(c) is an 8VSB signal-time waveform diagram in the fifth and sixth embodiments.

FIG. 69 is another block diagram of an image encoder in Embodiment 5 of the present invention.

FIG. 70 is a block diagram of an image encoder with one separation circuit in Embodiment 5 of the present invention.

FIG. 71 is a block diagram of an image decoder according to Embodiment 5 of the present invention.

FIG. 72 is a block diagram of one image decoder of a synthesizer according to a fifth embodiment of the present invention.

FIG. 73 is a time allocation diagram of a transmission signal according to the fifth embodiment of the present invention.

FIG. 74 (a) is a block diagram of an image decoder according to Embodiment 5 of the present invention; FIG. 74 (b) is a time allocation diagram of transmission signals of Embodiment 5 according to the present invention;

FIG. 75 is a time allocation diagram of a transmission signal according to the fifth embodiment of the present invention.

FIG. 76 is a time allocation diagram of a transmission signal according to the fifth embodiment of the present invention.

FIG. 77 is a time allocation diagram of a transmission signal according to the fifth embodiment of the present invention.

FIG. 78 is a block diagram of an image decoder according to a fifth embodiment of the present invention.

FIG. 79 is a time allocation diagram of transmission signals of three layers according to the fifth embodiment of the present invention.

FIG. 80 is a block diagram of an image decoder according to Embodiment 5 of the present invention.

FIG. 81 is a time allocation diagram of a transmission signal according to the fifth embodiment of the present invention.

FIG. 82 is a block diagram of a D1 image decoder according to Embodiment 5 of the present invention.

FIG. 83 is a frequency-time diagram of the frequency modulation signal of the fifth embodiment according to the present invention.

FIG. 84 is a block diagram of a magnetic recording / reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 85 is a diagram showing the relationship between the C / N and the layer number according to the second embodiment of the present invention.

FIG. 86 is a diagram showing the relationship between the transmission distance and C / N according to the second embodiment of the present invention.

FIG. 87 is a block diagram of a transmitter according to a second embodiment of the present invention.

FIG. 88 is a block diagram of a receiver according to a second embodiment of the present invention.

FIG. 89 is a relationship diagram of C / N-error rate according to the second embodiment of the present invention.

FIG. 90 is a diagram of a three-layer reception interference area according to the fifth embodiment of the present invention.

FIG. 91 is a diagram showing a 4-layer reception interference area according to the sixth embodiment of the present invention.

FIG. 92 is a hierarchical transmission diagram according to a sixth embodiment of the present invention.

FIG. 93 is a block diagram of a separation circuit according to a sixth embodiment of the present invention.

FIG. 94 is a block diagram of a synthesis unit according to a sixth embodiment of the present invention.

FIG. 95 is a transmission hierarchical structure diagram of Embodiment 6 according to the present invention.

Fig. 96 is a reception state diagram of a conventional digital TV broadcast.

FIG. 97 is a reception state diagram of digital TV hierarchical broadcasting according to Embodiment 6 of the present invention.

FIG. 98 is a transmission hierarchical structure diagram of Embodiment 6 according to the present invention.

FIG. 99 is a vector diagram of 16 SRQAM of Embodiment 3 according to the present invention.

FIG. 100 is a vector diagram of 32 SRQAM of Embodiment 3 according to the present invention.

FIG. 101 is a diagram showing a C / N-error rate relationship according to a third embodiment of the present invention.

FIG. 102 is a diagram showing a relationship between C / N and an error rate according to the third embodiment of the present invention.

FIG. 103 is a diagram illustrating a relationship between a shift amount n and C / N required for transmission according to a third embodiment of the present invention.

FIG. 104 is a diagram illustrating a relationship between a shift amount n and C / N required for transmission according to a third embodiment of the present invention.

FIG. 105 shows a distance from a transmitting antenna and a signal level during terrestrial broadcasting according to the third embodiment of the present invention.

FIG. 106 is a diagram illustrating a service area of 32 SRQAM according to a third embodiment of the present invention.

FIG. 107 is a service area diagram of 32 SRQAM of Embodiment 3 according to the present invention.

108A is a conventional frequency distribution diagram of a TV signal; FIG. 108B is a conventional frequency distribution diagram of a two-layer TV signal; and FIG. Is a frequency distribution diagram of the carrier group of the two-layered OFDM of the ninth embodiment. (E) is a diagram showing three threshold values of the three modified OFDMs of the ninth embodiment.

FIG. 109 is a diagram illustrating a TV signal time arrangement according to the third embodiment of the present invention.

FIG. 110 is a diagram showing the principle of the C-CDM according to the third embodiment of the present invention.

FIG. 111 is a diagram showing code assignment according to a third embodiment of the present invention.

FIG. 112 is a diagram showing code assignment when 36QAM is extended according to the third embodiment of the present invention.

FIG. 113 is a diagram illustrating a modulation signal frequency arrangement according to a fifth embodiment of the present invention.

FIG. 114 is a block diagram of a magnetic recording / reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 115 is a block diagram of a transceiver of a mobile phone according to a seventh embodiment of the present invention.

FIG. 116 is a block diagram of a base station according to a seventh embodiment of the present invention.

FIG. 117: Distribution diagram of communication capacity and traffic of the conventional method

FIG. 118 is a distribution diagram of communication capacity and traffic according to the seventh embodiment of the present invention.

FIG. 119 (a) is a conventional time slot arrangement diagram, and (b) is a time slot arrangement diagram of Embodiment 7 according to the present invention.

FIG. 120 (a) is a layout diagram of a conventional TDMA time slot. FIG. 120 (b) is a layout diagram of a TDMA time slot according to a seventh embodiment of the present invention.

FIG. 121 is a block diagram of a one-layer transceiver according to a seventh embodiment of the present invention.

FIG. 122 is a block diagram of a two-layer transceiver according to a seventh embodiment of the present invention.

FIG. 123 is a block diagram of an OFDM transceiver according to an eighth embodiment of the present invention.

FIG. 124 is an operation principle diagram of an OFDM system according to an eighth embodiment of the present invention.

FIG. 125 (a) is a frequency allocation diagram of a conventional modulation signal, and (b) is a frequency allocation diagram of a modulation signal according to the eighth embodiment of the present invention.

FIG. 126 (a) is a Weig of OFDM in Example 9.
(b) shows two sub-channels of OFDM of two layers weighted by the transmission power in the ninth embodiment. (c) shows the carrier interval in the ninth embodiment twice the weight.
(e) is a frequency distribution diagram of OFDM with carrier spacing without weighting in the ninth embodiment.

Fig. 127 is a block diagram of a transceiver of Embodiment 9 according to the present invention.

FIG. 128 (a) shows Tre in Examples 2, 4 and 5;
Block diagram of llis Encoder (Ratio1 / 2) (b) shows Trellis E in Examples 2, 4, and 5
Block diagram of ncoder (Ratio 2/3) (c) shows Trellis E in Examples 2, 4 and 5.
Block diagram of ncoder (Ratio 3/4) (d) Trellis D in Examples 2, 4, and 5
Block diagram of encoder (Ratio1 / 2) (e) Trellis D in Examples 2, 4, and 5
Block diagram of encoder (Ratio2 / 3) (f) Trellis D in Examples 2, 4 and 5
block diagram of encoder (Ratio3 / 4)

FIG. 129 is a time allocation diagram of an effective symbol period and a guard period according to the ninth embodiment;

FIG. 130 is a diagram showing the relationship between C / N and error rate in the conventional example and the ninth embodiment.

FIG. 131 is a block diagram of a magnetic recording / reproducing apparatus according to a fifth embodiment.

FIG. 132 is a diagram illustrating a recording format of a track on a magnetic tape and a traveling direction of a head according to a fifth embodiment.

FIG. 133 is a block diagram of a transceiver according to a third embodiment.

FIG. 134 is a frequency allocation diagram of a conventional broadcasting system.

FIG. 135 is a diagram showing the relationship between service areas and image quality when the three-layer hierarchical transmission system according to the third embodiment is used.

FIG. 136 is a frequency allocation diagram when the hierarchical transmission system according to the third embodiment is combined with FDM.

FIG. 137 is a block diagram of a transceiver when trellis coding is used in Embodiment 3.

FIG. 138 is a diagram showing a low-frequency signal of a part in the ninth embodiment,
Block diagram of transmitter / receiver when transmitting by M

FIG. 139 is a signal point arrangement diagram of 8-PS-APSK in the first embodiment.

FIG. 140 is a signal point arrangement diagram of 16-PS-APSK in the first embodiment.

FIG. 141 is a signal point arrangement diagram of 8-PS-PSK in the first embodiment.

FIG. 142 shows 16-PS-PSK (P
(S type) signal point layout

FIG. 143 is a diagram illustrating the relationship between the radius of the satellite antenna and the transmission capacity according to the first embodiment;

FIG. 144 is a Weighted OF in Example 9.
Block diagram of DM transceiver

FIG. 145A is a waveform diagram of the guard time in the case of a short multipath and symbol time hierarchical OFDM in the ninth embodiment; FIG. 145B is a guard time in the case of a long multipath in the ninth embodiment; OFDM waveform diagram

[FIG. 146] FIG. 146 (a) is a diagram illustrating the principle of guard time and symbol time hierarchical OFDM according to the ninth embodiment.

FIG. 147 is a diagram illustrating a sub-channel layout of a two-layer transmission system using power weighting in a ninth embodiment;

FIG. 148 is a diagram illustrating the relationship between D / V conversion, multipath delay time, and guard time according to the ninth embodiment.

FIG. 149 (a) is a time slot diagram of each layer in the ninth embodiment, (b) is a time distribution diagram of guard time of each layer in the ninth embodiment, and (c) is a guard time chart of each layer in the ninth embodiment. Time distribution diagram of time

FIG. 150 is an explanatory diagram of a three-layer hierarchical broadcasting system for a multipath in a relation diagram between a multipath delay time and a transmission rate diagram according to the ninth embodiment.

FIG. 151 shows GTW-OFDM and C-CDM of Example 9.
(Or CSW-OFDM) is an explanatory diagram of a hierarchical broadcasting system having a two-dimensional matrix structure in a relationship diagram between a delay time and a CN value.

FIG. 152 shows GTW-OFDM and C-CDM of Example 9.
(Or CSW-OFDM), time allocation diagram of TV signals of three layers in each time slot

FIG. 153. GTW-OFDM and C-CDM of Example 9
(Or CSW-OFDM) combined with a multi-path signal delay time, a CN value, and a transmission rate in a diagram illustrating a hierarchical broadcasting system having a three-dimensional matrix structure.

Fig. 154 is Power-Weighted of the ninth embodiment.
-OFDM frequency distribution diagram

FIG. 155. Guard-Time-OFD of Example 9
Layout diagram on the time axis of TV signals of three layers in each time slot when M and C-CDM are combined

FIG. 156 is a block diagram of a transmitter and a receiver in Embodiments 4 and 5.

FIG. 157 is a block diagram of a transmitter and a receiver in Embodiments 4 and 5.

FIG. 158 is a block diagram of a transmitter and a receiver in Embodiments 4 and 5.

FIG. 159 (a) is a 16VSB signal point arrangement diagram in the fifth embodiment, (b) is a 16VSB signal point arrangement diagram in the fifth embodiment (8VSB), and (c) is a 16VSB signal point arrangement diagram in the fifth embodiment ( (4VSB) (d) is a signal point arrangement diagram of 16VSB in the fifth embodiment (16VSB)

FIG. 160 (a) shows ECC E in Examples 5 and 6.
(b) ECC Encoder in Examples 5 and 6
Block diagram

FIG. 161 is an overall block diagram of a VSB receiver according to a fifth embodiment.

FIG. 162 is a diagram illustrating a transmitter according to a fifth embodiment.

FIG. 163 is an error rate / C / N value curve of Example 4 VSB and TC-8VSB

FIG. 164 is an error rate curve of subchannel 1 and subchannel 2 of Embodiment 4 VSB and TC-8VSB;

FIG. 165 (a) shows Ree in Examples 2, 4, and 5;
Block diagram of d Solomon Encoder (b) shows Reed Solo in Examples 2, 5 and 6.
block diagram of mon Decoder

FIG. 166. Reed Solom of Examples 2, 4, and 5
on error correction, operation flowchart

FIG. 167 is a block diagram of a deinterleave unit according to the second, third, fourth, fifth, and sixth embodiments.

FIG. 168 (a) is a diagram of an interleave and deinterleave table in Embodiments 2, 3, 4, and 5; FIG.

FIG. 169 is a diagram illustrating a 4-VSB and an 8-VS according to the fifth embodiment.
B, Comparison diagram of Redundancy of 16-VSB

FIG. 170: High in Examples 2, 3, 4, and 5
TV Receive to receive Priority signal
Block diagram of r

FIG. 171 is a block diagram of a transmitter and a receiver in Embodiments 2, 3, 4, and 5;

Fig. 172 is a block diagram of a transmitter and a receiver according to the second, third, fourth, and fifth embodiments.

FIG. 173 is a block diagram of an ASK type magnetic recording / reproducing apparatus according to a sixth embodiment.

[Explanation of symbols]

 Reference Signs List 1 transmitter 4 modulator 6 antenna 6a terrestrial antenna 10 satellite 12 repeater 23 first receiver 25 demodulator 33 second receiver 35 demodulator 43 third receiver 51 digital transmitter 85 signal point 91 first divided signal point Group 401 First image encoder 703 Reception area of SRQAM

Continued on the front page (31) Priority claim number Japanese Patent Application No. 5-349972 (32) Priority date December 27, 1993 (December 27, 1993) (33) Priority claim country Japan (JP) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04J 11/00 H04L 27/00-27/38

Claims (10)

(57) [Claims] 1. A transmitting apparatus for transmitting a plurality of data sequences including at least a first and a second data sequence by modulating a plurality of carriers having a frequency relationship orthogonal to each other, comprising: A first error correction encoding unit that performs a first error correction encoding process on a column; an interleave unit that interleaves an output of the first error correction encoding unit; and a second error signal that is output from the interleave unit. A second error correction encoding unit that performs a correction encoding process; a modulation unit that modulates an output of the second error correction encoding unit corresponding to the second data sequence and the first data sequence; An inverse Fourier transform unit for performing an inverse Fourier transform on an output of the modulation unit, wherein an output signal of the inverse Fourier transform unit includes a symbol signal and a guard signal; The second data sequence is modulated by changing the number of signal points allocated on a space diagram, and the period of the symbol signal is set to one of a plurality of types of periods.
Transmitter to select one. 2. A transmitting apparatus for transmitting a plurality of data sequences including at least a first and a second data sequence by modulating a plurality of carrier waves having a frequency relationship orthogonal to each other, comprising: A first error correction encoding unit that performs a first error correction encoding process on a column; an interleave unit that interleaves an output of the first error correction encoding unit; and a second error signal that is output to the interleave unit. A second error correction encoding unit that performs a correction encoding process; a modulation unit that modulates an output of the second error correction encoding unit corresponding to the second data sequence and the first data sequence; An inverse Fourier transform unit for performing an inverse Fourier transform on an output of the modulation unit, wherein the modulation unit uses the first data sequence and the second data sequence to assign a signal point to be assigned on a space diagram. Ete modulated, the frequency interval of the carrier, one selected transmitting apparatus from among a plurality of types of frequency intervals. 3. A signal transmitted by modulating a plurality of carrier waves having a frequency relationship orthogonal to each other with a plurality of data strings including at least a first and a second data string as an input signal, wherein the input signal is: On the transmitting side, the first data sequence and the second data sequence are modulated by changing the number of signal points to be allocated on a space diagram and inverse Fourier-transformed, and the input signal is a symbol signal and a guard signal. A period of the symbol signal is selected from a plurality of types of periods, a Fourier transform unit that performs a Fourier transform on the input signal, a demodulator that demodulates an output of the Fourier transform unit, and the second data A first error correction decoding unit that performs a first error correction decoding process on an output of the demodulation unit corresponding to a column, and an output of the first error correction decoding unit. Receiver including a deinterleaver for interleaving and a second error correction decoding unit that performs second error correction decoding process on an output of the deinterleaver. 4. A signal transmitted by modulating a plurality of carrier waves having a frequency relationship orthogonal to each other with a plurality of data strings including at least a first data string and a second data string as an input signal; On the transmitting side, the first data sequence and the second data sequence are modulated by changing the number of signal points to be allocated on a space diagram and inverse Fourier-transformed, and the frequency interval of the carrier is a plurality of types of frequencies. One selected from intervals, a Fourier transform unit for performing a Fourier transform on the input signal, a demodulator for demodulating an output of the Fourier transform unit, and an output of the demodulator corresponding to the second data sequence. A first error correction decoding unit for performing a first error correction decoding process; a deinterleave unit for deinterleaving an output of the first error correction decoding unit; Receiving device and a second error correction decoding unit that performs second error correction decoding process on the output of the interleaving unit. 5. A transmission device comprising the transmission device according to claim 1 and the reception device according to claim 3. 6. A transmission device comprising the transmission device according to claim 2 and the reception device according to claim 4. 7. A transmission method for transmitting a plurality of data sequences including at least a first and a second data sequence by modulating a plurality of carriers having a frequency relationship orthogonal to each other. After the first error correction coding process, the interleaving, and the second error correction coding process, the number of signal points to be allocated on the space diagram is changed between the first data sequence and the second data sequence. The output signal of the inverse Fourier transform unit includes a symbol signal and a guard signal, and the period of the symbol signal is set to one of a plurality of types of periods.
One transmission method to choose. 8. A transmission method for transmitting a plurality of data sequences including at least a first and a second data sequence by modulating a plurality of carriers having a frequency relationship orthogonal to each other. After the first error correction coding process, the interleaving, and the second error correction coding process, the number of signal points to be allocated on the space diagram is changed between the first data sequence and the second data sequence. A transmission method of performing modulation, inverse Fourier transform, and selecting one of a plurality of types of frequency intervals of the carrier. 9. A signal transmitted by modulating a plurality of carrier waves having a frequency relationship orthogonal to each other with a plurality of data sequences including at least a first and a second data sequence as an input signal; On the transmitting side, the first data sequence and the second data sequence are modulated by changing the number of signal points to be allocated on a space diagram and inverse Fourier-transformed, and the input signal is a symbol signal and a guard signal. One of the symbol signal periods is selected from a plurality of types of periods, and the input signal is Fourier-transformed and demodulated. Then, the first error correction decoding process and deinterleaving are performed on the second data sequence. And a receiving method for performing a second error correction decoding process. 10. A signal transmitted by modulating a plurality of carrier waves having a frequency relationship orthogonal to each other with a plurality of data sequences including at least a first and a second data sequence as an input signal, wherein the input signal is: On the transmitting side, the first data sequence and the second data sequence are modulated by changing the number of signal points to be allocated on a space diagram and inverse Fourier-transformed, and the frequency interval of the carrier is a plurality of types of frequencies. One of the intervals is selected, and the input signal is Fourier-transformed and demodulated.
Receiving a first error correction decoding process, deinterleaving, and a second error correction decoding process on the data sequence of (i).