JPH0550192B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) This invention relates to a transmission system for television signals, audio signals, data signals, etc., and aims to unify the configuration of receivers regardless of the type of signal.
The aim is to make the media configuration more flexible and to simplify the hardware. (Prior art) The conventional way of thinking about the use of transmission channels is to use different transmission formats for each service. A transmission method exclusively used for standard television is used for standard television, and a transmission method exclusively used for audio PCM broadcast is used for audio PCM broadcast. Although the above method has the advantage of being able to select the most suitable transmission method depending on the need, it also increases the cost of the receiver due to the need for receiving systems that support multiple transmission methods, and creates new services due to fixed channel usage. It has problems such as lack of flexibility. Therefore, in satellite broadcasting with a small number of channels, effective use of channels and simplification of receivers become major problems, and conventional methods are insufficient.

[Table] (Summary of the Invention) The purpose of the present invention is to eliminate the drawbacks of the above-mentioned conventional methods, unify the signal formats of multiple transmission lines having multiple transmission signal formats into packets, and transmit/receive RF (high frequency) By standardizing the stages, the cost of transmitters and receivers can be lowered, flexibility can be provided for new services, and transmission paths can be used more effectively. In other words, the program signal transmission system of the present invention includes a plurality of program signal sources and a plurality of modulators each having at least two different modulation methods in order to modulate carrier waves with signals from the signal sources. In the transmission method, the bands of modulated waves modulated by the signals from the plurality of program signal sources using the at least two different modulation methods are made to be substantially the same. , is characterized in that it performs signal processing and modulation of each program signal source. (Embodiment) FIGS. 2, 3, and 4 show the concept, signal format, and system configuration of the transmission system according to the present invention (hereinafter referred to as an integrated transmission system). Figure 2 shows the channel configuration of the transmission path of this integrated transmission method, but unlike the conventional channel usage shown in Figure 1, the channels named integration 1, integration 2, integration 3, etc. all have the same signal format. , and the program resources are different. FIG. 3 shows the frame structure of the signal format used here, and one frame using the packet method is composed of L packets. Of the L packets, M packets are used for voice or data, and N packets are used for transmitting television signals (L=M
+N). The packet signal format of the television signal is the time division multiplexed signal (TCI signal) shown in Figure 5.
The signal configuration is a time-division multiplexed burst synchronization signal, color signal, and luminance signal. The burst synchronization signal is a line (one unit that makes up a frame) synchronization signal, the color signal and luminance signal are both analog signals, and the packet signal format of the audio/data signal is the 6th one.
It consists of a line synchronization and data part using the digital signal system shown in the figure. The modulation method in the RF band is FM modulation for television packet signals and digital modulation for audio/data packet signals. In the integrated transmission system of the present invention, which packetizes signals and unifies the signal format, the signal format in the RF band is as follows.
Although the occupied time ratios of FM modulation and digital modulation are different, they are the same regardless of the channel, and even the demodulation stage of the receiver can be unified. FIG. 4 is a principle diagram of the integrated transmission system configuration. The parts 1 and 2 within the dotted lines in the figure are common to all transceivers, and this can be expected to reduce the cost of the transceiver. high definition television,
Television signal resources, such as standard television, are converted by an encoder 2 into the signal format shown in FIG. This is modulated by FM modulator 3 and switched to
Sent on SW ₁ 7th. In addition, audio and other data are converted into digital signals by an encoder 5, modulated by a digital modulator 6, and then sent to a switching device.
Input to SW ₁ 7. The switch 7 performs a time division operation, and performs time division switching between the television packet signal and the audio/data packet signal so that the frame structure shown in FIG. 3 is obtained. The output of the switch 7 becomes a signal for a broadcast channel or other transmission path. The above is the configuration and operation of the transmitter. The signal on the transmission path is input to the switch SW ₂ 8 of the receiver. The switch 8 performs a time division operation of separating the television packet signal and the audio/data packet signal according to the configuration shown in FIG. The television packet signal subjected to FM demodulation 9 is restored by a decoder 10 to the signal format of the transmitting side resource. On the other hand, the audio/data packet signal is also decodered, 12
is converted into the signal format of the transmitting side resource. As explained above, the signals a, b, c,
The signal formats of d and e are the same regardless of the signal resource. Each resource signal is packetized by an encoder and becomes a transmission signal in a signal format that does not depend on the type of resource. Next, more specific examples will be described. Figure 7 shows channels for television satellite broadcasting.
This is an example of the configuration of an integrated transmission system that uses channels to perform high-definition television broadcasting, multiplex standard television broadcasting, audio PCM broadcasting, and data broadcasting. The signal from the television signal resource 13 is converted by the band compression encoder 14 into a television packet signal of the time division multiplexed signal shown in FIG. On the other hand, the signal from the audio/data resource 17 is converted by the PCM encoder 18 into the signal format shown in FIG.
It becomes a data packet signal. Next, the signal is subjected to FM modulation 15 and digital modulation 19, respectively, and time-division switching 16 according to the frame structure, and a resource discrimination signal 43, which is information on switching timing of SW ₃ , is also multiplexed with the transmission signal. In the receiver, the resource discrimination signal is extracted by the discrimination signal separation circuit 44, and the FM demodulation 2 is controlled by this signal.
1. The digitally demodulated signal 23 is converted into a signal format of a television signal resource and an audio/data resource on the transmitting side by a band compression decoder 22 and a PCM decoder 24, respectively. In this integrated transmission system, parts 1 and 2 surrounded by dotted lines in FIG. 7 are the hardware that is shared. Therefore, the configurations of the television signal resource 13 and audio/data resource 17 differ depending on the signal to be transmitted. Next, the frame configuration will be explained. FIG. 8 shows the frame structure of a high-definition television with two audio channels. One frame is 1125 packets, television packet signal is 1052 packets,
The audio/data signal consists of 72 packets, to which is added a resource discrimination signal for distinguishing between a television packet signal and an audio packet signal. The above becomes the signal on the transmission path. The high-definition television resource mentioned above has a band of, for example, 20MHz, but the band compression encoder
The band is compressed to 8MHz and the signal format is shown in Figure 5.
The audio/data resource is stereo audio.
The signal is digitized by the PCM encoder 18 and has the signal format shown in FIG. The signal format of this transmission line becomes the basic pattern of this integrated transmission system. FIG. 10 shows the frame structure of four standard television channels and four audio channels. Therefore, as shown in FIG. 9, the television signal resource is provided with a multiplexing circuit 29, the audio/data resource is provided with a multiplexing circuit 34, and the receiver is provided with a separation circuit. Standard Television, 25,
Standard television, 26...28 represents resources such as standard cameras, VTRs, etc.
30, audio, 31, . . . 33 are audio resources such as tape recorders that output analog signals with a band of about 20 KHz. FIG. 12 shows the frame structure of an integrated channel that transmits two standard television channels, two audio channels, PCM audio, and data. All signals other than television signals are transmitted as audio/data packet signals using digital signals. Therefore, television signal resources and audio/data resources are provided with multiplexing circuits 37 and 42 as shown in FIG. 11, and outputs 35, 36, . . . 41 of VTRs, cameras, audio tape recorders, etc. serve as resources. . When multiplexing standard format television signals as shown in FIGS. 10 and 12, processing in the band compression encoder 14 includes cases where vertical calculations such as contour compensation are required. Advantageously, the signal format in one packet is
The signal format shown in FIG. In other words, the scanning lines on a standard television screen are compressed in time,
In time division multiplexing, one frame period is divided into upper and lower regions (α) and (β) (that is, odd and even field regions, respectively). and television packet signals.
As shown in FIG. 13b, the 246 packets are time-division multiplexed by dividing the areas (α) and (β) into color signals and luminance signals. One packet is converted as shown in FIG. In this way, even if adjacent lines on a standard television screen are time-axis compressed, time-division multiplexed, and converted to a signal of the same standard as a high-definition television signal, they will always be adjacent to each other in the same position, above and below. Therefore, in this packet configuration, the signal format remains in both areas (α) and (β), and the vertical calculation device for high-definition television signals is used as is to perform vertical calculations. It has the advantage of being able to perform arithmetic processing. Next, with regard to the embodiments of the frame structure of the present invention in FIGS. 8, 10, and 12, the basis for the specific allocation of the number of packets will be briefly explained. The bandwidth of one satellite broadcasting channel is approximately 27MHz. If the product BT of the bandwidth and the pulse period, which represents the effective rate of the transmission path, is taken as 1.2, which is an experimentally reasonable value from the eye opening ratio considering digital transmission, then 2-phase PSK (phase shift keying) per channel can be achieved. Digital transmission of 27 (MHz) x 1/1.2 (MHz/Mb・s ^- ) = 22.5 (Mb/s) becomes possible. This is 4 phase
For PSK, it is 22.5 (Mb/s) x 2 = 45 (Mb/s). Therefore, the bit rate that can be transmitted in one packet is 22.5 x 1/1125 = 20 (Kb/s) for 2-phase PSK and 20 x 2 = 40 (Kb/s) for 4-phase PSK. For audio transmission, the transmission bit rate is required to be 2.048 Mb/s, and the transmission bit rate is 2.048 Mb/s for both A mode (15 KHz mono 4 ch.) and B mode (20 KHz stereo 1 ch.) proposed to CCIR (Consultative Committee on International Radio Communications). P.S.K.
Then, 2.048 (Mb/s) ÷ 40 (Kb/s) ≒ 52 (packets) is required. High-definition television has a brightness signal of 20MHz and a color signal
7MHz, standard television has a brightness signal of 5MHz and a color signal of 1.25MHz. Vertical effective scan rate 0.935
Then, high-definition television is 1125 x 0.935 = 1052 (packets) For standard television, high-definition television 1
Attach the line to the standard television 2 line and get 525 x 0.935 = 491 491 ÷ 2 = 246 (packets). Based on these values, the structure of the number of packets in a frame is as shown in FIGS. 8, 10, and 12. In high-definition television, the audio is set to B mode and is stereo.
1ch.transmission. On standard television, the audio is A.
The mode shall be one stereo channel per standard television channel. The PCM audio in Figure 12 is A
Mode allows for 40ch audio transmission, and B mode allows for 20ch audio transmission. (Effects) By implementing the present invention, it becomes possible to unify the signal format of the transmission path into a packet, and it is possible to standardize the RF stage portion of the transmitter/receiver.
This reduces the cost of transceivers, provides flexibility for new services, and enables effective use of transmission lines. As mentioned in the example, by introducing the band compression method, even higher definition television (bandwidth 20M) can be achieved.
Hz) transmission, and has the advantage that the transmitter and receiver can share the RF stage as well as the encoder and decoder parts. This system allows transmission of one high-definition television channel, four standard television channels, or one to eight standard television channels and audio PCM transmission using a single signal format. If you do not need to transmit television signals,
All packets can be assigned to voice PCM transmission, data transmission, etc.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the channel configuration of the conventional transmission system, Figure 2 is a diagram showing the channel configuration of the integrated transmission system of the present invention, Figure 3 is a diagram showing the frame configuration of the present invention simply, and Figure 4 is a diagram of the present invention. A block diagram showing the configuration of the integrated transmission system of the invention, Figure 5 shows the time division multiplexing (TCI) television packet signal used in this system,
FIG. 6 is a digital voice/data packet signal used in this system, FIG. 7 is a block diagram showing the specific configuration of the integrated transmission system of the present invention, and FIGS.
Figures 0 and 12 are diagrams showing an embodiment of the frame structure of the present invention, Figures 9 and 11 are diagrams each showing resource composition of the embodiment of the present invention, and Figures 13 and 14 are diagrams showing the signal conversion of the present invention. FIG. 1...Television signal, 2...Encoder, 3...FM modulation, 4...Audio/data, 5...
...Encoder, 6...Digital modulation, 7...
_SW1 , 8... _SW2 , 9...FM demodulation, 10...decoder, 11...digital demodulation, 12...decoder, 13...television signal resource,
14...Band compression encoder, 15...FM modulation, 16...SW ₃ , 17...Audio/data resource, 18...PCM encoder, 19...Digital modulation, 21...FM demodulation, 22...Band compression Decoder, 23...Digital demodulation, 24...
PCM decoder, 25, 26, 27, 28, 35,
36...Standard television signal resource, 30,
31, 32, 33, 38, 39, 40...Audio signal resource, 41...Data resource, 29,3
4, 37, 42... multiplexing circuit.

Claims (1)

[Claims] 1. A system comprising a plurality of program signal sources and a plurality of modulators each having at least two different modulation methods in order to respectively modulate carrier waves with signals from the signal sources. In the transmission method, each program is configured such that the bands of modulated waves modulated by the signals from the plurality of program signal sources using the at least two different modulation methods are almost the same. A program signal transmission method characterized by subjecting the signal source to signal processing and modulation. 2. In the transmission system according to claim 1, one or more of the plurality of program signal sources are each configured by a signal obtained by time-division switching of a plurality of program signals. , a program signal transmission system characterized in that a modulated wave modulated using the above modulation system is time-division switched and transmitted. 3. A program signal transmission method according to claim 2, characterized in that each of the signals from the plurality of program signal sources is transmitted with an instruction signal for instructing the signal. . 4. In the transmission method according to any one of claims 2 and 3, when transmitting the signals of the plurality of program signal sources with divisions set for each fixed period, each of the different signals 1. A program signal transmission system characterized in that the lengths of the divided periods provided in each of the periods are set in an integer ratio to each other. 5 Claims 2, 3, and 4
In the transmission system described in any of the above, when converting a standard television signal to be compatible with a high-definition television signal system, each scanning line constituting the odd field and even field of the standard television signal is By compressing the time axis of each signal, and converting the signals obtained by compressing the time axis into a signal compatible with the high-definition television format by alternately time-division switching and outputting, a standard television signal is generated. A program signal transmission system characterized in that adjacent scanning lines of are arranged to be adjacent to each other even after being converted into a signal compatible with a high-definition television system.