JPH04364686A - Video audio multiplex transmission system - Google Patents

Abstract

PURPOSE:To send a video signal and an audio signal in a multiplex way regardless of simple constitution. CONSTITUTION:A horizontal synchronizing signal detection section 31 of a transmitter D detects a horizontal synchronizing signal in an inputted video signal. Then an audio signal is multiplexed onto a bottom of a horizontal synchronizing signal of a video signal by a multiplexer section 13 synchronously with the detection timing and the obtained signal is sent. On the other hand, a horizontal synchronizing signal detection section 43 of a receiver E detects the horizontal synchronizing signal in the sent signal. Then a demultiplexer section 41 extracts the audio signal multiplexed on the bottom of the horizontal synchronizing signal synchronously with the detection timing. Moreover, a replacement processing section 42 replaces a signal level for the horizontal synchronizing signal period with a prescribed value synchronously with the detection timing by the horizontal synchronizing signal detection section 43 to eliminate the audio signal and to reproduce the video signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video/audio multiplex transmission system for multiplex transmission of video signals and audio signals.

0002

[Prior Art] Focusing on the fact that the horizontal blanking period of a video signal has a fixed pattern, an audio signal is multiplexed onto the video signal by replacing the horizontal blanking period of the video signal with an audio signal. There is a video/audio multiplex transmission system. FIG. 3 is a block diagram showing the configuration of such a video/audio multiplex transmission system. In the figure, A is a transmitting device, B is a receiving device, and they are connected by an optical transmission path C.

[0003] The transmitter A includes an A/D converter (A/D) 1
1. Coding unit (COD) 12, multiplexing unit (MUX) 13
, a horizontal blanking signal detection section (HBL detection section) 14 and an optical transmission section (OS) 15. The video signal input to the transmitter A to be transmitted is digitized by the A/D converter 11 and then provided to the multiplexer 13 . On the other hand, the audio signal input together with the video signal is encoded by the encoding section 12 and then provided to the multiplexing section 13 .

The video signal is also given to the horizontal blanking signal detection section 14, and the horizontal blanking signal detection section 14 detects the horizontal blanking signal from the video signal. The multiplexer 13 multiplexes the audio signal onto the video signal by replacing the horizontal blanking signal period of the video signal with an audio signal based on the detection result from the horizontal blanking signal detector 14 . The signal obtained in this way is given to the optical transmitter 15. The optical transmitter 15 converts the applied signal into an optical signal and sends it to the optical transmission line C.

On the other hand, the receiver B includes an optical receiver (OR) 21
, separation section 22, horizontal blanking signal addition section (HBL addition section) 23, decoding section (DEC) 24, horizontal blanking signal generation section (HBL generation section) 25, and D/A conversion section (
D/A) Consists of 26. The light that has arrived via the optical transmission path C is received by the optical receiver 21 and converted into an electrical signal, which is then provided to the separating section 22 . The separation unit 22 extracts a signal of a predetermined portion (original horizontal blanking signal period) of the input signal, and supplies this to the decoding unit 24 as an audio signal. Further, the signals of other parts are applied to the horizontal blanking signal adding section 23 as video signals. The decoding unit 24 decodes the applied signal and reproduces the audio signal.

The horizontal blanking signal generating section 25 is supplied with a timing signal from the separating section 22, and generates a horizontal blanking signal at a predetermined timing to be added to the predetermined portion. The horizontal blanking signal generated by the horizontal blanking signal generating section 25 is given to the horizontal blanking signal adding section 23, where it is combined with the signal output from the separating section 22. In this way, a video signal including a horizontal blanking signal is reproduced. The video signal (digital signal state) thus reproduced is converted into an analog signal by the D/A converter 26 and then output.

[0007] As described above, the audio signal is multiplexed into the horizontal blanking signal period in the video signal and transmitted, and receiving device B only uses the portion of the received signal that corresponds to the horizontal blanking signal period as an audio signal. By extracting this portion and adding a horizontal blanking signal of a predetermined pattern to this portion, the video signal can be reproduced.

For example, in the case of an NTSC video signal, the phase of the burst signal included in the horizontal blanking signal is inverted by 180° for each line. Therefore, when the horizontal blanking signal is replaced with an audio signal and transmitted as described above, the transmitting device A detects the phase of the burst signal in the input video signal, adds that information, and transmits it. In device B, the horizontal blanking signal generator 25 generates two types of horizontal blanking signals, and these must be selected according to the added information and added to the received signal, resulting in a complicated configuration. It ends up.

[0009]

[Problems to be Solved by the Invention] As described above, in the conventional video/audio multiplex transmission system, most of the horizontal blanking signals are replaced with audio signals, which complicates the reproduction of the video signal on the receiving side. In particular, the phase of the burst signal is 180 degrees per line, such as the NTSC system signal.
If the signal is inverted, the configuration of both the transmitting side and the receiving side becomes extremely complicated.

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a video/audio multiplex transmission system capable of multiplex transmission of video signals and audio signals while having a simple configuration. It is about providing.

[0011]

[Means for Solving the Problems] The present invention includes a transmitting side device including a first detecting means such as a horizontal synchronizing signal detecting section for detecting a horizontal synchronizing signal period in the video signal;
and audio multiplexing means, such as a multiplexing section, for multiplexing the audio signal with the video signal during the period of the horizontal synchronization signal detected by the detection means, and the receiving side device A second device, such as a horizontal synchronization signal detection section, which detects the horizontal synchronization signal period in the signal sent from the side device.
a detection means, an audio extraction means such as a separation unit for extracting the audio signal multiplexed in the horizontal synchronization signal period detected by the second detection means from the signal sent out from the transmission side device; The apparatus is configured to include level replacement means, such as a replacement processing section, for replacing the level of the horizontal synchronization signal period detected by the second detection means of the signal sent from the transmitting side device with a predetermined level.

0012

By taking such measures, the audio signal is multiplexed and transmitted during the horizontal synchronization signal period of the video signal. In the receiving device, after extracting the audio signal multiplexed during the horizontal synchronizing signal period, the video signal is reproduced by replacing the horizontal synchronizing signal period with the original predetermined level. Therefore, the portion of the horizontal blanking signal period other than the horizontal synchronizing signal period is transmitted as is, and the receiving side does not reproduce the burst signal or the like.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a video/audio multiplex transmission system according to this embodiment. Note that the same parts as in FIG. 3 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In the figure, D is a transmitting device and E is a receiving device, which are connected via an optical transmission path C. The transmitting device D is
It consists of an A/D converter 11, an encoder 12, a multiplexer 13, an optical transmitter 15, and a horizontal synchronization signal detector 31. Further, the receiving device E includes an optical receiving section 21, a decoding section 24, a D/A
It consists of a conversion section 26, a separation section 41, a replacement processing section 42, and a horizontal synchronization signal detection section 43.

Next, the operation of the video/audio multiplex transmission system configured as above will be explained. First, in the transmitter D, the video signal digitized by the A/D converter 11 and the audio signal encoded by the encoder 12 are transferred to the multiplexer 1.
given to 3. In addition, the video signal is transmitted to the horizontal synchronization signal detection section 3.
1 is also given. The horizontal synchronization signal detection section 31 detects a horizontal synchronization signal in a given video signal, and outputs a timing signal according to the detection timing.

Now, the multiplexing section 13 does not select the audio signal during the horizontal blanking signal period as in the conventional case, but instead selects the audio signal during the horizontal blanking signal period.
Based on the timing signal output from the horizontal synchronization signal detection section 31, the video signal is detected as shown in FIG. The audio signal is multiplexed onto the video signal by superimposing the audio signal on the bottom of the horizontal synchronization signal. The signal thus obtained is converted into an optical signal by the optical transmitter 15 and sent to the optical transmission path C.

The optical signal transmitted through the optical transmission path C is converted back into an electrical signal by the optical receiving section 21 of the receiving device E, and the optical signal is returned to the electrical signal by the separating section 41.
and is given to the horizontal synchronization signal detection section 43. The horizontal synchronization signal detection section 43 detects a horizontal synchronization signal in the applied signal, and outputs a timing signal according to the detection timing. The separation unit 41 supplies the signal given from the optical receiver 21 to the replacement processing unit 42, but at this time, based on the timing signal output from the horizontal synchronization signal detection unit 31, the signal is multiplexed on the bottom of the horizontal synchronization signal. The extracted audio signal is supplied to the decoding section 24.

The replacement processing section 42 includes the horizontal synchronization signal detection section 3
Based on the timing signal output from 1, the separation unit 4
The level of the horizontal synchronizing signal portion in the signal given from 1 is replaced with a predetermined level (the bottom level of the horizontal synchronizing signal, which is defined as a constant value). Since the signal to be processed is in a digital state, this process is a process of replacing a corresponding portion of the signal with predetermined data corresponding to the predetermined level. Through this processing, the audio signal multiplexed at the bottom of the horizontal synchronization signal is removed, and the original video signal is reproduced. The video signal thus reproduced is converted into an analog signal by the D/A converter 26.

As described above, according to this embodiment, the audio signal is multiplexed on the bottom of the horizontal synchronization signal in the video signal and transmitted, and the receiving side receives the audio signal multiplexed on the bottom of the horizontal synchronization signal in this way. The audio signal is obtained by extracting the audio signal, and the video signal is obtained by replacing the part where the audio signal was multiplexed with a predetermined level (the bottom level of the horizontal synchronization signal), so the horizontal blanking signal period The back porch after the horizontal synchronizing signal and the burst signal multiplexed on this back porch are transmitted as they are, and there is no need to take any consideration into them even if they are NTSC video signals. Furthermore, since the audio signal is multiplexed at the bottom of the horizontal synchronization signal, which is at a constant level, the audio signal can be removed by a very simple process of replacing it with predetermined data corresponding to a predetermined level. This can be achieved through configuration. Furthermore, the bottom level of the horizontal synchronization signal is 0
If it is V, a simple configuration such as applying a gate can be used.

Note that the present invention is not limited to the above embodiments. For example, in the above embodiment, a video/audio multiplex transmission system that digitally transmits video signals and audio signals is exemplified, but the present invention can also be applied to a system that transmits analog signals as they are. In addition, various modifications can be made without departing from the gist of the present invention.

[0021]

According to the present invention, the transmitting side device includes a first detecting means such as a horizontal synchronizing signal detecting section for detecting a horizontal synchronizing signal period in the video signal, and the first detecting means. and audio multiplexing means, such as a multiplexing unit, for multiplexing the audio signal with the video signal during the detected horizontal synchronization signal period, and the receiving device is configured to transmit the audio signal sent from the transmitting device. a second detection means, such as a horizontal synchronization signal detection section, which detects the horizontal synchronization signal period in the signal, and the audio signal multiplexed with the horizontal synchronization signal period detected by the second detection means; The level of the horizontal synchronization signal period detected by the audio extraction means, such as a separation unit, extracted from the signal sent from the transmission side device, and the second detection means of the signal sent from the transmission side device. Since it is configured to include a level replacement means such as a replacement processing unit for replacing the level with a predetermined level, the video/audio multiplex transmission system is capable of multiplex transmission of video signals and audio signals with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a video/audio multiplex transmission system according to an embodiment of the present invention.

FIG. 2 is a diagram clearly showing how an audio signal is multiplexed onto a video signal.

FIG. 3 is a diagram explaining the prior art.

[Explanation of symbols]

D... Transmitting device, E... Receiving device, C... Optical transmission line, 11... A
/D conversion unit, 12... encoding unit, 13... multiplexing unit, 15...
Optical transmitter, 31... Horizontal synchronization signal detector, 21... Optical receiver, 24... Decoder, 26... D/A converter, 41... Separator,
42...Replacement processing unit, 43...Horizontal synchronization signal detection unit.

Claims (1)

[Claims] 1. In a video/audio multiplex transmission system for multiplex transmission of a video signal and an audio signal, a transmitting side device includes a first detecting means for detecting a horizontal synchronizing signal period in the video signal, and a first detecting means for detecting a horizontal synchronizing signal period in the video signal; and audio multiplexing means for multiplexing the audio signal on the video signal during the period of the horizontal synchronization signal detected by the detection means, and the receiving device is configured to detect the horizontal synchronization signal in the signal sent from the transmitting device. a second detection means for detecting a synchronization signal period; and an audio extraction means for extracting the audio signal multiplexed in the horizontal synchronization signal period detected by the second detection means from the signal sent from the transmitting side device. and level replacing means for replacing the level of the horizontal synchronizing signal period detected by the second detecting means of the signal sent from the transmitting side device with a predetermined level. Audio multiplex transmission system.