JPS60206284A - Transmission system of still picture signal - Google Patents

Abstract

PURPOSE:To realize a variety of programs in a limited transmission band by means of a high-fidelity still picture transmission system with high picture quality and high tone quality by modulating a carrier by means of a television video signal and a sound digital signal through use of different modulation systems and by utilizing directly a satellite broadcast. CONSTITUTION:Plural high-fidelity still picture programs consisting of high quality pictures and sounds are time-division-multiplexed by a still picture broadcasting transmitter 2, and transmitted to a broadcast satellite by a high-fidelity television transmitter 3. If a band width of 27MHz of a satellite broadcast channel 1 is fully used and a digital sound signal is time-division-multiplexed as a modulation system in an RF band, a signal transmission speed of the digital sound becomes 32Mb/sec, compared with a conventional 2.048Mb/sec, and in case of only a sound, transmission of stereo 16 channels can be possible accordingly.

Description

[Detailed Description of the Invention] Technical Field High-definition television signals require a wider transmission band, for example, about 27 MH2, than standard television signals in order to increase the definition of the screen. When transmitting a high-definition television signal using a wireless network, it is not possible to obtain a sufficient transmission band (because more channels must be inserted into a limited band). Therefore, the video signal of high-definition television is subsampled, and a complete video signal of one frame is transmitted over multiple frame periods. For moving parts, the bandwidth is compressed and transmitted according to the movement, and even if the definition of the image decreases, it is not affected much by the customization of human vision.

Along with the transmission method of the Akane quality television signal as described above, there is a means for temporarily storing the sub-sampled and transmitted signal in the receiving device and interpolating the video signal to restore the definition of the image. It is set up.

Focusing on the configuration of such a receiving apparatus for broadcasting satellite high-definition television signals, it has been proposed to utilize its storage unit for purposes other than receiving high-definition television signals. For example, the storage unit can be used to store information data signals, character signals, graphic signals, etc., and can be exchanged with other receiving devices, displayed received information, or stored in advance. You can practice drawing by comparing the shape and the shape the recipient draws on the display screen, or you can store information such as games and exchange information sounds between the input device, storage unit, and display device. High-definition television receivers can be used for multiple purposes using known means, such as playing games by exchanging information with input devices, storage units, and display devices built into other receivers in remote locations. can be used.

Furthermore, we focused on the fact that the transmission method of high-definition television signals is a method that performs subsampling and interpolation, and took advantage of the fact that once video information is sent for still images, there is no need to send the same information again. It has also been proposed to send information other than video information, such as text signals, graphic signals, audio signals, and other control signals, during other periods when no video information is sent.

In the future, it is possible that it will be applied to the broadcasting of various types of information as a new media, but in this case, the standard of high-definition television signal transmission, frame synchronization, line synchronization, transmission bandwidth, etc. will be the basics. ~ other transmission signals, such as current standard television signals,
By arranging and transmitting audio signals, data signals, character signals, graphic signals, etc., various synchronization signals and control signals can be shared, and the equipment values can be simplified when mutually converting these signals and converting formats. .

For example, the current standard television signal (NTSC)
, ao frames/second, horizontal life 525 lines/frame, if the format is converted to a high-definition television signal, 4 frames of the standard television signal can be accommodated in one frame of the commodity television signal. Therefore, a 4-channel standard television signal is transmitted as a 1-channel high-definition television signal, and on the receiving side, the storage sound is used to record n [standard of the desired channel] in one frame of the vortex-definition television signal. By extracting the information for one frame of a standard format television signal and converting it back to the standard format, it is possible to receive and reproduce the standard format television signal.

The number of scanning lines of a high-definition television signal is 1126.
There are 20) G (Z band stereo audio signals 1
When transmitting the channel as a 4-phase PSK signal, approximately 5
It can be transmitted using only two packets. Of course, each signal is given an identification signal to distinguish the contents of the signal.

Based on the various considerations to date as mentioned above,
The present invention relates to the transmission of still image signals by integrating these methods and using a high-definition television signal transmission system.

Conventional technologyStill image broadcasting is a method that can transmit a large number of programs consisting of color still images such as text, graphics, photographs, and audio over one channel of broadcast radio waves, and can be used for information programs such as news and weather forecasts. It is possible to simultaneously provide a wide variety of programs such as , educational programs, and cultural programs. The still image transmission system that has been developed and tested so far is composed of medium-quality images and audio, with the aim of increasing the number of broadcasts (111), and has nine programs, approximately 50 programs per channel. Ta.

By the way, in the future when broadcasting satellites are used to provide all services for still images, the required performance will require a high-definition screen with a large amount of information per screen and a display with a large number of characters. I can predict that. Furthermore, by providing high quality audio, it is thought that a new field of services different from video broadcasting will be opened up. Considering these points, although the current medium-quality still image transmission system allows for a large number of programs, it cannot meet the above-mentioned requirements in terms of quality.

In order to further improve the quality of audio, POM digitization is generally used, which involves time-division multiplexing the video signal and POM digital audio signal in the baseband and then FM modulating it for satellite broadcast transmission. Even if the transmission band after FM modulation is 27 MHz, the baseband can only be about 8 MHz, and the amount of information that can be transmitted by a POM digital signal depends on this baseband width. There was a problem in that high-quality still image transmission did not allow for a large number of programs.

SUMMARY OF THE INVENTION The present invention eliminates the conventional drawbacks mentioned in the prior art section, and
This is a still image signal transmission method that directly uses satellite broadcasting to transmit high-quality still images with high picture and sound quality, and to realize a large number of programs in a limited transmission band.

In addition, as mentioned in the technical field section, multiple subsampling and interpolation methods have been attempted for the transmission of high-definition television signals, and FM modulation, which is used as an S/N countermeasure in satellite broadcasting, has For example, 27 MHz)k
Even if it cannot be used directly, a method has been established that can transmit high-quality video signals, so the video signal will be transmitted using this high-quality FM modulation transmission method, and the audio will be digitized because of its high quality. This is a high-quality still image signal transmission method that uses a different modulation method that can utilize the broadcast transmission band more efficiently, thereby efficiently transmitting a large number of programs.

That is, the still image signal transmission method of the present invention is a method for transmitting still image signals and audio signals by arranging the television video signal and the audio signal in chronological order. During the period when the television video signal is transmitted, and during the period when the television video signal is not transmitted, during a period that is an integral multiple of the frame period of the television signal, 1) digitize the IJ recorded sound multiple signal and convert it into an audio digital signal; Upon transmission, the television video signal and the audio digital signal:
They are characterized in that carrier waves are modulated using different modulation methods.

Embodiment A configuration example of a high-quality still image signal transmission system according to the present invention is shown in FIG. While medium-quality still image signal transmission uses a standard television system, high-quality still image signal transmission uses a high-definition television system. That is, the image is a still image according to the high-definition television standard, which is typified by, for example, a number of scanning lines of 1125 and an aspect ratio of 5.28. For example, B-mode (20 KHz stereo, sampling frequency 48 KHz, 16-bit linear quantization) sound proposed by OIR (International Radio Communication Consultative Committee) for television satellite broadcasting is applied.

A large number of high-definition still picture programs composed of high-quality images and sounds are time-division multiplexed by a still picture broadcasting transmission equipment 2, and transmitted to a broadcasting satellite by a high-definition television transmission station 8. On the receiving side, the still image program receiver 7 extracts the program selected by the viewer using the program selection button 8 from among the received signals.
A screen corresponding to the program is written to the frame memory included in the high-definition television decoder 5, and the screen stored in the memory is displayed on the monitor 6 until the next screen is received.
to play repeatedly. Also, the audio is extracted and reproduced from the signal of the corresponding audio channel.

FIG. 2 shows an example of video and audio frame allocation in the case of the configuration example of the transmission system shown in FIG. Video and sound jlj are time-division multiplexed and transmitted frame by frame. Various values can be selected for this video and audio frame number ratio depending on the number of programs that can be simultaneously serviced, the presentation time of still images of each program, the audio product 1e■, etc., but here, as an example, This figure shows a case where 14 frames of audio are sent after 2 frames of video are sent. In the video frame, images of each program are intermittently allocated as the program progresses, and in the audio frame, the audio of each 11r #+1 is transmitted in parallel for a pre-allocated period.

In the example shown in Figure 2, the video has two frames because the processing system before transmitting the high-definition television signal uses a multiple sub-sandal two-frame-one-order method as the video band compression technology. As an example, Karadechiri has a voice of 14
The reason why it is called a frame is explained below.

The target audio is the B mode of the television satellite broadcasting proposed for OIR (20KH2 stereo, sampling frequency 48KHz, 16-bit linear quantization) as described above.
The sound quality is high, and this stereo channel 1 or 20
)G(z) To digitally transmit two monaural channels, 2.0+8 Mb including error correction pits etc.
/s It is known that the code transmission speed is safe.

This quality of audio is produced without FM adjustment like video signals.
If the 27 MHz bandwidth of one satellite broadcasting channel is used to its fullest, and all the digital audio signals are time-division multiplexed in the RF band using the FJJJ method, the digital audio code transmission rate will be 82 megabits/second (Mb/s). Therefore, if only audio is transmitted, it becomes possible to transmit the stereo channel 16 compared to the previous 2.048 Mb/s.

Looking at the correspondence between stereo channel 16 transmission and the number of video frames, visually the stereo channel 1 is video 1.
．． The result is 875 frames (80÷16), and from the relationship of integer ratios, the 16th channel of the stereo is reduced to 14 channels,
If two frames of video are inserted instead, the configuration as shown in FIG. 2 will be obtained.

Note that the code transmission rate of 82 Mb/s depends on the modulation method.
K (Minimum 5hift Keying
) or 0QPSK (0ffset, Quadra
ture Phase 5hift Keying)
If the method is updated once a month, the bit error p rate will be JO-8 or less with an 0/N ratio of 10 dB (2 (including the IB margin) within the 27 MHz bandwidth of satellite broadcasting, and the error correction and detection method This comes from the fact that by combining/IJ, it becomes possible to transmit data at a sufficiently low rate.

If the ratio of video and audio is 2:14 as in the 21st Y1, or ζ), the number of programs will be 1 with stereo audio.
Four programs can be sent simultaneously, and the average presentation time of images for each program is approximately 7.5 seconds ((16÷80V×'14)).

The transmission Gj to the broadcasting satellite uses FM modulation for video, and uses all efficiency modulation methods suitable for 4'+ts star transmission, such as MSK or 0QPSK, as described above, and uses FM modulation for video and R.
Time division multiplexing is performed in the F@ area.

If the second voice is made into Akane sound quality monaural, the number of programs in the above example would be 28, and the average presentation time of the image would be 15 seconds, which would be a little longer, but generally the information contained in high-definition still images is limited to text, etc. It is considered that there will be no problem even if the presentation time is increased to 15 seconds.

The conventional method described in the prior art section involves time-division multiplexing of the video signal and POM digital audio signal in the baseband, then FM modulation and transmission to the broadcasting satellite, and the RF stage of the present invention. In order to make a clearer comparison with the time division multiplexing system, let's consider how many B-mode stereo channels can be used without video in the former.

In the case of medium-quality still image broadcasting (standard television broadcasting), the clock frequency of the digital signal is 5.73 Mz(L5) for the baseband bandwidth of 4.2 MHz.
8 x 815), so in high-definition still image broadcasting, the baseband bandwidth is about 8 MHz, but the clock frequency of the digital signal is Fl, 73 x 8/4.2.
= approximately 10.9 MHz. If you add the above-mentioned B-mode stereo to this, 2.048 MH per channel
Since the clock frequency of Z is high, if only stereo is installed, it will be null to 5 channels.

There is a multilevel transmission method as a method to increase the code transmission speed without changing the baseband bandwidth.
If four-value transmission is performed using pulses with a clock frequency of Hz,
The code transmission rate is 22 Mb/s and 7S:9, and the B mode stereo has 10 channels. However, when multilevel transmission is used, the error rate customization against noise decreases, and in the case of four-level transmission, the theoretical value of the error rate at an 0/N ratio of 10 dB is 9 x 10, which makes it unusable.

As described above, in the RF stage time-division multicasting system of the present invention, the number of carriers that can actually transmit audio is improved from 5 channels to 16 channels even if only audio is limited to VC.The effect of the present invention is to implement the present invention. This makes it possible to broadcast more programs with high-quality images and audio at full speed within the limited radio waves of satellite broadcasting, creating a still image broadcasting service that can meet the demands of a wide range of viewers. It can be performed.

Images are superior to audio in that they provide a list of information, but in Nakashinami's still image broadcasts, it was not possible to include a lot of information in one screen. This point was unsatisfactory compared to other media such as everyday still images, such as printed matter, but the high-definition still image broadcasting according to the present invention can contain a lot of information in one frame, so it has been improved. It is a method that can meet a wide range of needs for still image broadcasting.

Furthermore, the transmission method uses different video signals, the J1'i1 method, and the f-circle method for digitized multi-channel audio signals, and time division multiplexes them in the iRF band. It is capable of transmitting both high-quality video and high-quality audio, which is a digital signal of vortex velocity, and is suitable for broadcasting satellites that require highly efficient use of transmission power.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a system for transmitting high quality still images according to the present invention, and FIG. 2 is an image showing high quality still image signal transmission according to the present invention. FIG. 3 is a diagram illustrating an example of audio distribution format. DESCRIPTION OF SYMBOLS 1... Akane quality still image inspection set, 2... Still image broadcast transmission device, 3... High definition television transmitter, 4... High definition television receiver, 5... High definition television・Decoder, 6...Monitor, 7 ・Still image program receiver, 8
...Program selection button. 1°, ″f revised applicant Japan Broadcasting Corporation 4 and I, project I Figure 2

Claims (1)

[Scope of Claims] L. A method for transmitting a still image signal and an audio signal by arranging a television video signal and an audio signal in chronological order, wherein said television is transmitted for a period that is an integral multiple of the frame period of the television signal. When transmitting a television video signal and not transmitting the television video signal, the audio signal is digitized and transmitted as an audio digital signal for a period that is an integral multiple of the frame period of the television signal,
A still image signal transmission system, characterized in that a carrier wave is modulated by the television video signal and the audio digital signal using mutually different modulation methods. 2. In the transmission method according to claim 1,
A first instruction signal for instructing the television video signal is attached to the television video signal, and a second instruction signal different from the first instruction signal for instructing the audio digital signal is attached to the audio digital signal. A still image signal transmission method characterized by transmitting a still image signal. & In the transmission method according to any one of the first and second claims, when the audio signal is digitized, the bit frequency is set to an integer ratio with the horizontal scanning frequency and vertical scanning frequency of the television signal. A still image signal transmission method characterized by having the following relationship. 4% Permissible In the transmission method according to any one of the eighth top side of claims 1 and 2, during a period in which the television video signal is not transmitted, any signal other than the first and second instruction signals is transmitted. A still image signal transmission method characterized in that other information signals such as control signals are also transmitted.