JPH01168186A - Television signal decoder - Google Patents

Abstract

PURPOSE:To obtain a picture having a wider aspect ratio than that of the existing picture and to receive the picture signal of the existing system without any hindrance by providing a means applying synchronizing detection to a television signal and a means applying time base is compression and time base expansion. CONSTITUTION:The signal sent from a sender side is received by an antenna, subjected to frequency conversion in the intermediate frequency band by a tuner, band limit by a 1st filter, synchronization detection by a 1st detector by using a carrier I1 and becomes a main signal. Moreover, the output of the tuner is subject to band limit by a 2nd filter, subjected to synchronization detection by a 2nd detector by using a carrier I2 shifted for its phase and becomes a multiplex signal. The main signal is subject to time base compression by a time base compression circuit in a signal processing circuit, and separated into a luminance signal Yc and color signal Cc in the YC separation circuit 23, the signal subjected to time base compression at the sender side is subject to signal expansion and the luminance signal Ys and the color signal Cs by the YC separation circuit 35 into a luminance signal Ys, a color signal Cs and subjected to time axis compression. Thus, the existing television signal is received without fault and the pattern with a wide aspect ratio is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a television signal decoding device, and in particular, the current television system has an aspect ratio (horizontal to vertical ratio) of 4:
This invention relates to a television signal decoding device that reproduces television signals that are suitable for transmitting scene information having a larger aspect ratio than that of 3, and that is compatible with current television systems. .

Conventional technology Japan's current NTSC [National Television Network]
System Committee (National Te1e-
vision system comm1tee)
] More than 25 years have passed since color television broadcasting began in 1960. In the meantime, various new television systems have been proposed in response to demands for high-definition screens and improvements in the performance of television receivers. Furthermore, the content of the programs provided is changing from simple studio programs and relay programs to programs with higher quality and more realistic images, such as cinema-sized movie broadcasts.

Against this background, the Japan Broadcasting Corporation (NHK) proposed a high-definition television system. (For example, Literature Special Feature on High Definition Television (Television Society Journal Vol. 36,
No. 10, 1982)) The contents are 1125 scanning lines, 2:1 interlaced scanning, and a luminance signal horizontal bandwidth of 20.
MHz, and high definition, and from the perspective of visual engineering such as the sense of scene and scene, the aspect ratio (the ratio of the width to the height of the screen) was increased to 5.
:3. This system has already been almost completed in closed systems, and with the start of satellite broadcasting, satellite
proposed the MUSE method (Reference, Tasuku Ninomiya et al., Satellite 1-channel transmission method for high-definition television (MUSE) (IEICE technical research report IE84-72, 1984)) that transmits high-definition television in the channel band. , experiments are underway.

On the other hand, current broadcasting uses 525 scanning lines, 2:1 interlaced scanning,
Luminance signal horizontal bandwidth 4.2MHz, aspect ratio 4:3
It has various specifications. (For example, refer to the literature Broadcasting Technology Library, Color Television, edited by Japan Broadcasting Corporation, Japan Broadcasting Publishing Association, 1961.) When a movie is provided as the above program, the screen size should be adjusted to the aspect ratio of the current television receiver. Either the ends are cut off to make it 4:3, or invalid screens are placed at the top and bottom of the screen, and the aspect ratio of the valid screen is sent out to match the movie value.

Problems to be Solved by the Invention As mentioned above, when transmitting and servicing movie programs and immersive screens in current broadcasting, some parts of the screen are cut or the screen area becomes smaller, so producers have to There was a problem in that the intention was not fully conveyed. Furthermore, if a signal with an aspect ratio larger than 4=3 is simply transmitted, a normal receiver will not be able to receive the signal. When the number of scanning lines and frame frequency are the same as those of current broadcasting, in order to obtain the same horizontal resolution, an aspect ratio of m:3 (m is a real number of 4 or more) requires a video bandwidth m/4 times that of the current broadcasting.

However, from the point of view of effective use of radio wave resources, the transmission band cannot be expanded unnecessarily.

Therefore, a device has been invented that transmits a video having an aspect ratio of 4:3 or more, that is, a wide aspect ratio video. This will be explained below. - In general, in order to obtain the same horizontal resolution when the number of scanning lines and frame frequency are the same, a system with an aspect ratio of 5:3 must have an aspect ratio of 4:
:The bandwidth required for transmission is 1.25 times that of 3. Therefore, by stacking the increased bandwidth in the first and third quadrants of the "time-vertical" two-dimensional frequency, or in the high range of the color signal, the current television system can be improved while maintaining the horizontal resolution. The idea is to transmit wide aspect ratio video within the band. (Unexamined Japanese Patent Publication 1986)
(Refer to Publication No. 213185) However, if the video with an aspect ratio of 5:3 is transmitted as is using such conventional technology, when received by a current television receiver,
The disadvantage is that the image becomes vertically long, making it incompatible with current television receivers.

Furthermore, in the case of moving images, the increased bandwidth cannot be multiplexed into the first and third quadrants on the "time-vertical" two-dimensional frequency due to crosstalk, resulting in a decrease in horizontal resolution.

The present invention has been made in view of the above, and an object of the present invention is to provide a television signal decoding device that is compatible with current television systems and that reproduces television signals having a wider aspect ratio. do.

Means for Solving the Problems In order to solve the above problems, the television signal decoding device of the present invention includes a frequency axis multiplexed signal separating means for separating frequency axis multiplexed signals, and a frequency axis multiplexed signal separating means for separating a luminance signal and a chrominance signal. means for demodulating the color signal, means for compressing the time axis, means for expanding the time axis of the time axis multiplexed signal, and means for time axis compressing the frequency axis multiplexed signal to convert the luminance signal and the chrominance signal. It is equipped with means for separating.

Effects of the present invention With the above-described configuration, current television broadcasting can be received without any trouble by time axis compression, and by performing synchronous detection, time axis compression, time axis expansion, etc., it is possible to receive a horizontally long screen with a wide aspect ratio. can be obtained.

Embodiment Hereinafter, a television signal decoding apparatus according to an embodiment of the present invention will be described with reference to the drawings. Figure 2(a) is
An example of a display screen of a current television is shown in FIG. 2(b), which shows a composite video signal for one scanning line period near the center of the screen. Since the aspect ratio is 4:3, the second
As shown in the display example in Figure (a), part of the left and right circles among the three circles may be missing. Figure 3(a) shows an example of a display screen with a larger aspect ratio than the current one, for example 5:3, and Figure 3(a) shows a video signal for one scanning line period near the center of the screen. , Figure 3(C) is a composite video signal in which the video signal shown in Figure 3(b) is rewritten so that the scale of the time axis is equal to that in Figure 2, and a synchronization signal and color burst signal are added. This is what is shown. Note that the aspect ratio is not limited to 5:3. Third
If the aspect ratio is increased as shown in FIG. 2(a), more video information can be obtained than on the screen shown in FIG. 2(a). Here, with the current television receiver,
Even when receiving a video signal with an aspect ratio of 5:3,
In order to maintain compatibility (that is, to maintain compatibility), which is a hindrance compared to the conventional method, the time axis is expanded for the television signal during the period displayed on the screen of the current television receiver. As can be seen by comparing Figure (b) and Figure 3 (C), when the signal in Figure 3 (C) is received by a current television receiver, the original image is a circle, but , it becomes a vertically elongated ellipse, so it is necessary to expand the time axis of the signal shown in Figure 3 (C).In other words, the original image is captured with a horizontally elongated aspect ratio of m:3 (m is a real number of 4 or more) than before. In this case, the time axis of the image signal corresponding to the portion displayed on the screen of the current television receiver may be expanded by a factor of m/4.

Furthermore, in order to obtain screen information with an aspect ratio of m:3, the remaining signal portions are sent by time axis multiplexing for low frequency components and frequency multiplexing for high frequency components. Furthermore, C
For CD cameras and the like that do not require a picture tube during the horizontal retrace period, it is not necessarily necessary to extend the time axis of the image signal corresponding to the portion displayed on the screen of a current television receiver. In other words, this is because the horizontal retrace period is shortened, and there is a margin in the time axis direction.

FIG. 4 is a spectrum diagram showing a frequency axis multiplexing method on the transmitting side according to an embodiment of the present invention. FIG. 4(a) is a spectrum diagram of a television signal subjected to vestigial sideband amplitude modulation in the current television system. Here, a case is shown in which the lower sideband of the video carrier wave P is a residual sideband. FIG. 4(b) shows a multiplexed signal, in which a carrier wave P2 having the same frequency as the video carrier wave P and having a different phase is connected to the carrier wave P2.
The residual sideband amplitude is modulated to remove the residual sideband.

FIG. 4(C) shows the signal obtained by multiplexing the signals in FIG. 4, etc.) onto the television signal in FIG. 4(a). Although the band of the signal modulated by the multiplexed signal starts from a frequency 1.25 MHz lower than that of the carrier wave P, it is not limited to this, and may start from a frequency 4.25 MHz lower, for example.

Next, a television signal processing method on the transmitting side in an embodiment of the present invention will be described. Of the electrical signals obtained by capturing an original image with an aspect ratio larger than 4:3, the portion corresponding to the aspect ratio of 4:3 is subjected to residual sideband amplitude modulation of the video carrier wave using a composite video signal in which the time axis is expanded. do. Then, a carrier wave having the same frequency as the video carrier wave but with a different phase is added to the residual sideband amplitude modulated television signal, and a composite signal obtained by time-extending the high frequency components obtained from the remaining part of the electrical signal is used to generate both sides of the television signal. The signals are band-amplitude modulated and band-limited by a Nyquist filter, which has frequency characteristics opposite to those up to the video intermediate frequency amplification stage of the receiver, and then multiplexed. Note that the composite signal obtained by compressing the low frequency components obtained from the remaining part of the electrical signal on the time axis is time-axis multiplexed on at least a part of the video signal period or a part of the retrace period. FIG. 6 shows an example of time axis expansion, compression, and multiplexing on the transmitting side. In the present invention, it is assumed that, for example, a television signal synthesized by the above-described signal processing is received.

Next, a processing method of a television signal decoding apparatus according to an embodiment of the present invention will be described. The video intermediate frequency band signal output from the tuner is band-limited by a filter that removes orthogonal distortion, as shown in FIG. 5(a). When this is expressed as a vector, it becomes as shown in FIG. 5(b). Since the video baseband signal becomes substantially double-sideband due to the filter, if the upper and lower sidebands are the vector aUs and the vector aL, their combined vector is a, which consists of only the component orthogonal to the vector I2. Furthermore, since the multiplexed signal has residual sidebands when considering the carrier wave 2 as the center, the upper and lower sidebands become vectors bLls and vectors bL, and when decomposed into orthogonal vectors, they become vectors b2 and b2. That is, when synchronous detection is performed using the carrier wave I2, orthogonal distortion due to vector al, vector b, and components does not occur, and only the multiplexed signal components can be demodulated. Note that the band of the signal modulated by the multiplexed signal starts from a frequency 1.25 MHz lower than the carrier wave I2, but it is not limited to this. If there is, it is possible to demodulate multiplexed signals with a band of 4.25 MHz.

FIG. 1(a) is a block diagram of a television signal decoding apparatus according to an embodiment of the present invention. In FIG. 1(a), 1 is an antenna, 2 is a tuner, 3 is a first filter, and 4
is a first wave detector, 5 is a carrier wave regeneration circuit, 6 is a second filter, 7 is a phase shifter, 8 is a second wave detector, 9 is a main signal output terminal,
10 is a multiplexed signal output terminal, 11 is a signal processing circuit, and 12 is a demodulation circuit. A signal sent from the transmitting side is received by an antenna 1, frequency-converted by a tuner 2 to an intermediate frequency band, and band-limited by a first filter 3. Although an antenna is illustrated, the transmission path is not limited to a wireless system, but may be a wired system.

The band-limited signal is supplied to a first detector 4 and a carrier recovery circuit 5. The carrier wave regeneration circuit 5 regenerates the carrier wave (2) for synchronous detection. The band-limited signal is synchronously detected by the first detector 4 using the carrier wave I. The output of the first detector 4 is used as the main signal. Further, the output of the tuner 2 is band-limited by a second filter 6 as shown in FIG. 5(a). Carrier wave 1 obtained from carrier wave regeneration circuit 5. The band-limited signal is synchronously detected in the second detector 8 using the carrier wave I2 whose phase is shifted by the phase shifter 7 as shown in FIG. 5(b), for example. Note that the phase shift direction of the carrier wave (2) is made to match that of the sending side. The detection output becomes a multiplexed signal. The main signal and multiplexed signal are input to the signal processing circuit 11.

Further, as a frequency axis multiplexing method for multiplexed signals, a method of multiplexing the television signal in the first and third quadrants, which are conjugate positions with the color subcarrier in the time-vertical frequency plane, can be considered. (Refer to Japanese Patent Application Laid-open No. 59-171387.) In this case, in the signal demodulated to baseband on the receiving side, the difference between the signals where at least the phase of the color subcarrier is the same between fields, or the phase of the color subcarrier is determined. The main signal and the multiplexed signal can be separated by summing the signals whose phases are opposite to each other.

FIG. 1(b) is a block diagram showing an example of the internal configuration of the signal processing circuit 11 of FIG. 1(a). 21 is a main signal input terminal, 34 is a multiplex signal input terminal, 23.35 is a YC separation circuit, 24.37 is a color demodulation circuit, 22.36.38.3
9 is a time axis compression circuit, 25, 26, 27 is a time axis expansion circuit, 28, 30, 32 is a switch, 29, 31, 33 is an adder, 40 is a luminance signal Y output terminal, 41 is a color signal I output Terminal 42 is a color signal Q output terminal. The main signal input from the main signal input terminal 21 is time-domain compressed by a time-domain compression circuit 22, and then separated by a YC separation circuit 23 into a luminance signal Yc and a color signal C9. Of the Yc signals output from the YC separation circuit 23, as shown in FIG. It is axially expanded and input to the adder 29. Time axis compression circuit 22
, the time axis expansion circuit 25 performs reverse time axis processing and time axis adjustment in contrast to the time axis expansion and time axis compression on the transmitting side, respectively, and maintains a normal time relationship by integrating transmission and reception. make it possible to do so. The same applies to the time axis expansion circuit and time axis compression circuit described below. Note that time axis expansion and time axis compression can be performed, for example, by changing the writing and reading clocks to the memory. The color signal Cc, which is the output of the YC separation circuit 23, is processed by the color demodulation circuit 24 into 1. The signal is demodulated by Qc times the signal. Like the Yc multiplied signal, the Ic signal, Q signal, and Yc multiplied signal are time-axis compressed on the transmitting side, and the signal further time-axis compressed by the time-axis compression circuit 22 is sent to the time-axis expansion circuit 2.
6.27, the time axis is extended by adder 31.
33. On the other hand, the multiplexed signal inputted from the multiplexed signal input terminal 34 is sent to the YC separation circuit 35 as a luminance signal Y3,
It is separated into a color signal C5. The color signal C3 is sent to the color demodulation circuit 37
The I5 signal and the Qs times signal are demodulated. Luminance signal Y.

is time-base compressed by the time-base compression circuit 36, added to the output of the time-base expansion circuit 25 by the adder 29, and inputted to the switch 28. The switch 28 outputs the output Yc signal of the YC separation circuit 23 as the luminance signal Y during the period corresponding to the aspect ratio portion of 4:3, and outputs the output of the adder 29 as the luminance signal Y during the other periods. Similarly, (2) the double signal is time-base compressed by the time-base compression circuit 38, added to the output of the time-base expansion circuit 26 by the adder 31, and inputted to the switch 30.

It is assumed that the switch 30 outputs the output IC signal of the color demodulation circuit 24 as the color signal I during the period corresponding to the aspect ratio portion of 4:3, and outputs the output of the adder 31 as the color signal I during the other periods. Similarly, the Q signal is time-domain compressed by the time-domain compression circuit 39, and the output of the time-domain expansion circuit 27 and the adder 33
are added and input to the switch 32. It is assumed that the switch 32 outputs the output Qc times the output of the color demodulation circuit 24 as the color signal Q during the period corresponding to the aspect ratio portion of 4:3, and outputs the output of the adder 33 as the color signal Q during the other periods. The luminance signal Y, color signal I, and color signal Q are connected to R-
It may be displayed on a monitor or the like as a G-B signal.

Note that when the color signal is not superimposed on the time-axis multiplexed signal, the time-axis expansion circuits 26 and 27 and the adders 31 and 33
It is not necessary to input the outputs of the color demodulation circuits 38 and 39 to the switching devices 30 and 32, respectively.

Note that the time axis compression circuit 22 restores the television signal by compressing the time axis expanded portion of the television signal having a horizontal aspect ratio so that current television broadcasting can be received without any problems. It is for. In other words, as can be seen by comparing Figure 2 (b) and Figure 3 (C), in order to receive the current broadcasting image without changing its aspect ratio, it is necessary to change the current television signal on the time axis. It needs to be compressed. The compression ratio is determined by the aspect ratio. However, if the display is a liquid crystal display or the like and does not require a CRT during the retrace period, it is not necessarily necessary to compress the time axis. When receiving current television signals, a screen with an aspect ratio of 4:3 is projected near the center, and the remaining area of the receiver screen, which has a horizontal aspect ratio, is darkened by blanking etc. What is necessary is to perform processing such as the following.

Effects of the Invention As is clear from the above description, the present invention includes means for synchronously detecting television signals, and means for time axis compression and time axis expansion, and transmits scene information with a larger aspect ratio than the current one. By reproducing a television signal that is compatible with current televisions and can be received without problems, it is possible to obtain a screen having a horizontally longer aspect ratio than the current television. Furthermore, current television signals can also be received without any problems.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram of a television signal decoding device according to an embodiment of the present invention, and FIG. 1(b) is a block diagram of a television signal decoding device in an embodiment of the present invention.
) is a block diagram showing an example of the internal configuration of the signal processing circuit of
FIG. 2(a) is a front view showing an example of a display screen of a current television, FIG. 2(b) is a waveform diagram showing a composite video signal during one scanning line period near the center of the screen, and FIG. Diagram (a)
is a front view of an example of a display screen when the aspect ratio is set to, for example, 5=3, FIG. 3(b) is a waveform diagram showing a video signal during one scanning line period near the center of the screen, and FIG. C) is adjusted so that the scale of the time axis is equal to that of Figure 2.
A waveform diagram showing a composite video signal obtained by rewriting the video signal shown in Figure (b) and adding a synchronization signal and a color burst signal,
Figure 4(a) is a spectrum diagram of a television signal modulated with vestigial sideband amplitude in the current television system, and Figure 4(b) is a signal different from the signal shown in Figure 4(a). The demodulated and band-limited spectrum diagram, Figure 4 (C) is the 4th spectrum diagram.
A spectrum diagram in which the signal shown in Figure (b) is multiplexed with the signal in Figure 4 (a), Figures 5 (a) and 5 (b) are spectrum diagrams and vector diagrams when demodulating multiplexed signals, and Figure 6 The figure is a waveform diagram showing time axis compression, time axis expansion, and time axis multiplexing positions. 7... Phase shifter, 3... First filter,
6... Second filter, 4... First detector, 8... Second detector, 22.36.38.3
9... Time axis compression circuit, 25.26°27...
...Time axis expansion circuit, 23.35...YC
Separation circuit, 24, 37... Color demodulation circuit. Name of agent: Patent attorney Toshio Nakao 1 idiot Figure 4
,1-7,1 yo3wa-1,2503,5
84,5 M'lL number (MHz) (b) P2 □ Ichino 2507.25 Orchid number [Hz1 M K11l, CM Hz] 3k -'-J -JI
s - 11 transfer J skin Fig. 5 c - Package 1 carrier liquid S - 11 tone carrier wave (α) Fig. 6 Image 4j, Signal period Horizontal return period

Claims (3)

[Claims] (1) Of the electrical signals obtained by capturing an original image with an aspect ratio larger than 4:3, those with an aspect ratio of 4:3
The first signal corresponding to
Frequency domain multiplexing signal separation means for time domain expanding and frequency domain multiplexing of high frequency components of the signal, time domain compression of low frequency components and separating the frequency domain multiplexed signal from the time domain multiplexed television signal. , a means for compressing the time domain and separating the luminance signal and the chrominance signal, a means for demodulating the chrominance signal, a means for expanding the time domain multiplexed signal in the time domain, and a means for dividing the frequency domain multiplexed signal into the luminance signal and the chrominance signal. A television signal decoding device characterized by comprising means for separating signals into signals and compressing the time axis. (2) The frequency-axis multiplexed signal separation means includes a filter for removing orthogonal distortion and means for synchronously detecting a carrier wave having the same frequency as the video carrier wave and having a different phase. The television signal decoding device as described. (3) The frequency-axis multiplexed signal separation means includes means for calculating the difference of signals in which at least the color subcarriers have the same phase between fields, or the sum of the signals in which the color subcarriers have opposite phases. A television signal decoding device according to claim 1, characterized in that: