JPH01208086A - Picture transmitting system - Google Patents

Abstract

PURPOSE:To process as a voice frame at a receiving side and to simplify a picture transmitting system by inserting a control signal corresponding to the first signal of a serial sound signal for one sample detected when a sound signal is A/D-converted by a transmitting part to the prescribed position in the picture frame together with the sound signal and multiplexing and transmitting it. CONSTITUTION:A control signal DV corresponding to the first signal of the serial sound signal for one sample in which the sound signal is A/D-converted 1, P/S-converted 2 with a converter 21 of the transmitting part of a picture transmitting system and detected with the converter 21 at a picture frame generating circuit 22 is inserted into the prescribed position of a picture frame signal together with the sound signal. The output of the circuit 22 and an A/D- converted 30 picture signal are multiplexed with a multiplexing part 23 and sent to a transmission line. A picture signal is separated from the transmitted multiplexing signal with a separating part 24 of a receiving part, a picture frame signal is removed by a separating circuit 25, a serial sound signal and the control signal DV are separated and processing is executed by a D/V- converter 26.

Description

[Detailed Description of the Invention] [Summary] Regarding an image transmission line method in which image signals and audio signals are sampled separately using a transmission line clock and multiplexed, a special circuit for CMI encoding and audio frame addition is provided. The purpose of this system is to realize a compact system that does not require any hardware. an image frame generation circuit that inserts and multiplexes a control signal corresponding to the first signal of the serial audio signal together with the audio signal at a predetermined position in the image frame signal; and a multiplexing section that multiplexes the information.

[Industrial application field]

The present invention relates to an image transmission system, and more particularly to an image transmission system in which an image signal and an audio signal are sampled separately using a transmission line clock and multiplexed.

There are various methods for multiplexing and transmitting image signals and audio signals, and in such cases, the method used differs depending on the following conditions.

■A method in which a clock synchronized with the input signal is used as the sampling clock for the image signal, and a sampling clock obtained by dividing the transmission line clock is used for the audio signal.

The features of this method are as follows.

(1) Since the image signal is encoded in synchronization with the input signal, the image quality of the image signal is very high.However, as an image encoding device, the sampling clock of the image signal is different from the transmission line. To align the data, E
An S (elastic store) circuit and a panzer memory circuit are required, resulting in a large-scale hardware configuration of the device.

(2) Since the image signal is multiplexed on the clock of the transmission line and transmitted, by matching the frame period of the transmission line with the audio signal, the image signal can be transmitted using just the frame of the image signal without adding a separate frame for the audio signal. It is possible to synchronize the clock and data of the signal and the audio signal. In this case, the audio signal multiplexing circuit can be configured with simple hardware.

(3) Since the image signal is buffered and multiplexed, the multiplexing position of the audio signal can be freely selected.

■A method in which both the image signal sampling clock and the audio signal sampling clock are transmitted using clocks that are unrelated to the transmission line clock. (There are cases where the sampling clock of the video signal is synchronized with the human signal as in (2), and cases where a fixed oscillator is used separately from the transmission line.) The characteristics of this system are as follows.

(+) The hardware configuration of the image device is maximized, and the audio signal also requires a data buffering function.

(2) Since the transmission path clock can be selected completely arbitrarily, this method is the only one that can be used as a low bit rate image transmission device. (For example, the image signal sampling clock 14.
(3) Since image signals are buffered and multiplexed, the multiplexing position of audio signals can be freely selected.

■A method in which the transmission line clock is divided and used for both the video signal sampling clock and the audio signal sampling clock.

The features of this method are as follows.

(1) Direct analog transmission without compressing the image signal and transmitting it.
When transmitting a digitally converted signal, there is no need for a buffering circuit, so the method is simple and the hardware configuration can be very economical.

Furthermore, when transmitting an image signal after band compression, a fixed length encoding method is used instead of a variable length encoding method, which does not require a buffering circuit, resulting in a relatively simple hardware configuration.

(2) Since the audio signal also uses a frequency-divided transmission line clock, a simple hardware configuration is required when multiplexing it with the image signal.

Among the above methods, method (■) is the best as it requires a smaller overall hardware configuration when simultaneously transmitting audio signals, and this method can be used to further reduce the hardware size. is requested.

[Conventional technology]

The following types of audio signal multiplex transmission methods are used when converting an image signal from analog to digital (without band compression), converting the linearly encoded signal to P/S (parallel-serial), and transmitting it as is. be.

(A) A method in which data assigned to an audio signal is CMI encoded and transmitted using the frame structure shown in FIG.

The configuration of this system is shown in Figure 6, where the audio signal is
/D converter 1 performs A/D conversion, and P/S converter 2 performs P/S conversion.
It is converted into a serial signal as shown in FIG. 7(a), and the CMI encoder 3 converts it into a CMI signal as shown in FIG. 7(b).
After encoding, it is multiplexed with the image frame signal generated by the multiplexing circuit 4 (the shaded area in FIG. 7 (b)), and further multiplexed with the image signal in the multiplexing unit 5, and then It is converted and transmitted to the receiving side.

On the receiving side, the audio signal is decoded by going through exactly the reverse procedure to the above.

(B) As shown in FIG. 8, a method in which an audio frame signal (only one bit of Fl may be used) is added to the audio signal data and transmitted.

The configuration of this method is shown in Figure 9, and on the transmitting side,
An audio frame addition circuit 11 is used in place of the CMI encoder 3 in FIG. 6, where an audio frame is constructed and added to the audio code, and then multiplexed with the image signal in the same manner as above.

In the receiving section, this added audio frame is sent to a separation circuit 1.
2, the audio signal is extracted, decomposed, and decoded.

[Problem that the invention sought to solve]

The above conventional example (A) requires a CMI encoding circuit and a decoding circuit.

Furthermore, in the conventional example (B), a frame configuring section is required in the audio frame adding circuit of the transmitting section, and a frame extracting section and a decomposing section are required in the decomposing circuit of the receiving section.

Therefore, the present invention does not require circuits for CM1 encoding and audio frame addition as described above in an image transmission line system in which image signals and audio signals are sampled and multiplexed separately using a transmission line clock. The aim was to realize a small hardware scale.

[Means to solve the problem]

FIG. 1 is a diagram conceptually showing an image transmission system according to the present invention to achieve the above object, and 21 is a diagram showing an audio signal A.
A converter 22 converts the control signal DV corresponding to the first signal of one sample of the serial audio signal detected by the converter 21 into a serial signal by converting it into a serial signal by converting the audio signal into a serial signal. The image frame generating circuit 23 is a multiplexing section that multiplexes the output of the image frame generating circuit 22 and the image signal, and the transmitting section includes these components.

The receiving section detects and decodes the beginning of the audio signal by detecting the control signal from the received signal.

[For production]

In the image transmission system of the present invention shown in FIG. 1, a converter 21 A/D converts an audio signal and outputs it as a serial signal as shown in FIG. When the first output audio signal of the converter 21 is generated, the image frame generating circuit 22 correspondingly inserts the control signal DV and the serial audio signal into a predetermined position of the image frame. By multiplexing in this manner, a control signal section shown in the frame structure of FIG. 3 is generated. Then, this control signal section is transferred to the multiplexing section 23.
The signal is multiplexed with the image signal and transmitted as a signal having the frame structure shown in the entire figure in FIG.

Thereby, by detecting the control signal DV on the receiving side, it is possible to easily detect the first position of the serial audio signal, that is, the audio frame.

〔Example〕

FIG. 4 shows the entire communication system incorporating the transmitter of the image transmission system shown in FIG. The signals are converted into parallel digital signals and sent to the multiplexer 23.

Furthermore, the converter 21 shown in FIG.
/S converter 2, and the other parts are the first
It is similar to the figure. The receiving section includes a separating section 24 that separates the image signal from the received signal, a separating circuit 25 that removes the image frame signal from the remaining received signal and separates it into a serial audio signal and a control law signal D, and a control signal DV. A converter 26 (S/
The image signal is obtained as an analog image signal by the D/A converter 31.

Next, the operation of this embodiment will be explained.

First, the audio signal is converted into a parallel digital signal upstream from the A/D converter every sample by the transmission line clock, and then converted into a serial digital audio signal (see Figure 2) by the P/S converter 2 as an image. It is sent to the frame generation circuit 22. When this serial audio signal is first output from the P/S converter 2, the MSB or LSB of the parallel input bit of the P/S converter 2 becomes "H" level, so that the serial audio signal is output from the P/S converter 2. A control signal DV (see FIG. 2) is also sent to the image frame generation circuit 22.

The image frame generation circuit 22 generates a control signal section as shown in FIG. This starts with image frame F1~
Generate F3 as usual and create a predetermined image frame F4
The control signal DV is inserted into the part (see FIG. 5), and the first audio signal A1 is inserted. This control signal DV goes to "H" level in response to the first signal of the serial audio signal of each sample, and the P/S converter 2 outputs the MSB or LSB.
While this is being detected, a signal of "T7°" level is inserted.

The 1-bit control signal portion multiplexed in this manner is multiplexed with the 8-bit parallel signal from the A/D converter 30 by the multiplexer 23 and transmitted as a multi-frame configuration as shown in FIG.

In the receiving section, the separation section 24 first separates the image signal into 8-pin parallel signals, and the D/A converter 31 obtains the image signal. Received signals other than the image signal are separated into a serial audio signal and a control signal DV in a separation circuit 25. That is, the third
The image frame signal is removed from the control signal portion shown in the figure, and the bin 1 at the position corresponding to frame F4 (see FIG. 5) is removed.
- is at the "It" level, it is determined to be the control '11 signal DV and output, and the audio signals A1 and A2 at the predetermined positions are output.
, . . . (see Figure 2, t1.Q) are separated and output as serial signals.

The S/P converter of the converter 26 converts the serial audio signal from the separation circuit 25 into a parallel signal after the control signal DV is input, and the D/A converter decodes the analog signal using this parallel signal. do.

(Effects of the Invention) As described above, according to the image transmission method according to the present invention, the serial audio signal corresponding to one sample is detected when the audio signal is A/D converted into a serial signal in the transmitter. Since the control signal corresponding to the first signal of the image frame signal is inserted into a predetermined position in the image frame signal together with the audio signal, multiplexed, and transmitted, the receiving side can process this control signal as an audio frame signal. Therefore, CMI
Encoding circuits and special audio frame addition circuits are no longer required, and the circuit can be significantly miniaturized.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of the image transmission system according to the present invention, Fig. 2 is a diagram showing the relationship between the audio signal and the control signal DV, Fig. 3 is a diagram showing the frame structure used in the present invention, Fig. 4 5 is a block diagram showing an example of an image transmission method according to the present invention; FIG. 5 is a diagram showing a frame configuration used in a conventional example; FIG. 6 is a block diagram showing an example of a conventional image transmission method; Figure 8 is a diagram showing the structure of audio encoded data using CMI encoding, Figure 8 is a diagram showing audio frames added to the audio signal, and Figure 9 is a block diagram showing another conventional image transmission method. , is. In FIG. 1, 21... converter, 22... image frame generation circuit, 23... multiplexing unit. In the figures, the same reference numerals indicate the same or corresponding parts. , -, No; 7 Control word D Image to be sent to a small invention - Power type quasi-first sale H Figure 1 Voice transmission A At A2 A3 A4 A
s A6 A7 A8 A9 AIOAll
At2 At3 Ha 14 system J Taro D Shioto: 1
- Controls used for non-invention Figure 2 Frame configuration according to the invention Figure 3 Conventional multiplexed frame configuration Figure 5 1 Example of foot table configuration Figure 6 ``Sound No. 1'' MSE3 1 −+ ::::−−−−−−−− Figure 7 Structure of CMI encoded data

Claims (2)

[Claims] (1) In an image transmission method in which an image signal and an audio signal are sampled separately using a transmission line clock and multiplexed, the transmitting section includes a converter (21) that A/D converts the audio signal and converts it into a serial signal. and 1 detected by the converter (21)
an image frame generation circuit (22) that inserts and multiplexes a control signal (DV) corresponding to the first signal of the serial audio signal for samples at a predetermined position in the image frame signal together with the audio signal; An image transmission system characterized by comprising a multiplexing section (23) that multiplexes the output of the circuit (22) and an image signal. (2) The receiving unit includes a separating unit (24) that separates the image signal from the received signal, and a separation unit that removes the image frame signal from the remaining received signal and separates it into the serial audio signal and the control signal (DV). a circuit (25), and a converter (26) that detects the first position of one sample of the audio signal using the control signal (DV), converts the serial signal at the position into a parallel signal, and performs D/A conversion. An image transmission system according to claim 1, comprising: