JP2002125207A - Signal transmitter and signal receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a signal transmission system adopting the DVI(Digital Visual Interface) standards that can transmit an audio signal together with a video signal. SOLUTION: A multiplexer section 102 of the signal transmitter of this invention multiplexes the video signal with the audio signal subjected to time base compression on the basis of a multiplex control signal and the transmitter transmits the multiplexed signal via a data line 106 to the signal receiver of this invention. The signal receiver uses a demultiplexer section 103 to demultiplex the video signal/audio signal multiplexed signal received via the data line 106 on the basis of a demultiplex control signal into the original video signal and the original audio signal. Furthermore, the signal transmission system employs the horizontal synchronizing signal or vertical synchronizing signal of the video signal for the multiplex control signal and the demultiplex control signal, the transmitter side applies time base compression to the audio signal and multiplexes the audio signal with gaps of the video signal and the receiver side applies time base expansion to the received signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmitting device and a signal receiving device.

[0002]

2. Description of the Related Art Conventional DVI (Digital Visual Interface)
ce) A standard signal transmission system will be described with reference to FIG. FIG. 26 is a diagram showing a configuration of a conventional transmission system. In the figure, reference numerals 2601 to 2603 denote TMDS encoders / serializers provided on the transmission side, which perform TMDS encoding on input component signals such as RED, GREEN, and BLUE, serialize them, and transmit them to a transmission path. Reference numerals 2604 to 2606 denote TMDS decoders / recoveries provided on the receiving side, which decode the received signals by TMDS and recover them to recover component signals.

[0003] A DE (data enable) signal is an RE signal.
This is a signal indicating a period during which a component signal such as D, GREEN, or BLUE exists, and is a HIGH active signal. For example, a period during which the DE signal is LOW is a horizontal synchronization signal period or a vertical synchronization signal period of a video.

A CTL (control) signal CTL
0, CTL1, CTL2, and CTL3 are prepared as control signals. However, these signals are unused in the current DVI standard. Specifically, the signal level is always 0.

A conventional signal transmission system configured as described above will be described. The transmitting-side TMDS encoder / serializers 2601 to 2603 convert an 8-bit input video signal (RGB signal) into 10-bit data, serialize the signal, and transmit the signal to a transmission path. 8 bits / 1
The purpose of the 0-bit conversion is to reduce data change points and to make the data suitable for high-speed transmission. In the TMDS encoder / serializers 2601-2603, CL
Two bits of the T signal are converted into 10 bits and transmitted to the transmission path. Further, the DE signal is also encoded and serialized together and transmitted to the transmission path.

[0006] TMDS decoder / recovery 2 on the receiving side
In 604 to 2606, the 10-bit serial data received from the transmission path is converted into the 8-bit color signal, the DE signal, and the C signal.
The TL signal is decoded and expanded into two bits.

[0007]

SUMMARY OF THE INVENTION However, DVI
The standard is a standard for transmitting only a video signal, and there is a problem that a conventional signal transmission system cannot transmit an audio signal.

An object of the present invention is to provide a signal transmitting apparatus and a signal receiving apparatus capable of realizing a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal. Aim.

[0009]

According to a first aspect of the present invention, there is provided a signal transmitting apparatus connected to a signal receiving apparatus via a transmission line. A time axis compression unit for compressing the signal of the time axis, a multiplex control signal generator for generating a multiplex control signal based on the second signal, and a multiplex control signal generated by the multiplex control signal generator. Signal multiplexing means for multiplexing the first signal compressed on the time axis, the second signal, and the third signal and outputting the multiplexed signal as the multiplexed signal; and transmitting the multiplexed signal and the multiplexed control signal to the signal receiving device. Signal transmitting means for transmitting.
This makes it possible to realize a signal transmission system that transmits the first, second, and third signals through the same transmission path.

According to a second aspect of the present invention, there is provided a signal transmitting apparatus connected to a signal receiving apparatus via a transmission path, wherein the first signal is compressed by a time axis compressing means; 2, a multiplex control signal generator for generating a multiplex control signal based on the second signal, the first signal compressed on the time axis using the multiplex control signal generated by the multiplex control signal generator, and the second signal. And a signal transmitting means for transmitting the multiplexed signal to the signal receiving apparatus, and a signal multiplexing means for multiplexing the signal and the third signal and outputting the multiplexed signal as a multiplexed signal. . Thereby, without transmitting the multiplex control signal to the signal receiving device,
A signal transmission system that transmits the first, second, and third signals through the same transmission path can be realized.

According to a third aspect of the present invention, in the signal transmission apparatus according to the first or second aspect, the first signal is an audio signal, and the second signal is a horizontal signal. A synchronization signal or a vertical synchronization signal.
Is a video signal. As a result, it is possible to realize a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal.

According to a fourth aspect of the present invention, there is provided a signal transmitting apparatus according to the DVI transmission standard for transmitting an RGB video signal as serial data, wherein the first video signal transmits the RGB video signal as serial data. A second mode for transmitting three signals of a luminance signal, a color difference signal, and an audio signal in addition to the mode, and a switching unit for switching between the first mode and the second mode;
It is characterized by the following. As a result, it is possible to realize a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal.

According to a fifth aspect of the present invention, there is provided a signal receiving apparatus connected to a signal transmitting apparatus via a transmission line, wherein the first signal multiplexed on the time axis from the signal transmitting apparatus is First receiving means for receiving a multiplexed signal in which the second signal and the third signal are multiplexed; second receiving means for receiving a multiplexed control signal from the signal transmitting device;
Separating means for separating the multiplexed signal received by the first receiving means into the first and second signals by using the multiplex control signal received by the second receiving means; And a time axis extending means for extending the time axis of the first signal separated by the above. This makes it possible to realize a signal transmission system that can transmit the first, second, and third signals through the same transmission path.

According to a sixth aspect of the present invention, there is provided a signal receiving apparatus connected to a signal transmitting apparatus via a transmission line, wherein the first signal, which is time-division multiplexed from the signal transmitting apparatus, Receiving means for receiving a multiplexed signal in which the second signal and the third signal are multiplexed; detecting means for detecting the second signal from the multiplexed signal; and a second signal detected by the detecting means. Multiplex control signal generating means for generating a multiplex control signal based on a signal; separating means for separating the multiplex signal into the first, second, and third signals using the multiplex control signal; And a time axis extending means for extending the first signal separated by the time axis on a time axis. Thereby, a multiplexed signal can be separated without receiving a multiplexed control signal from the signal transmission device, and a signal transmission system capable of receiving the first, second, and third signals on the same transmission path can be realized. .

According to a seventh aspect of the present invention, in the signal receiving apparatus according to the fifth or sixth aspect, the first signal is an audio signal and the second signal is a horizontal signal. A synchronization signal or a vertical synchronization signal.
Is a video signal. As a result, it is possible to realize a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal.

According to a eighth aspect of the present invention, in the signal receiving apparatus of the DVI transmission standard for receiving RGB video signals as serial data, a first signal receiving apparatus for receiving the RGB video signals as serial data is provided. In addition to the mode, it has a second mode for receiving three signals of a luminance signal, a color difference signal, and an audio signal, and has a switching unit that switches between the first mode and the second mode.
It is characterized by the following. As a result, it is possible to realize a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. The embodiment described here is merely an example, and the present invention is not necessarily limited to this embodiment.

(Embodiment 1) A signal transmission system according to Embodiment 1 will be described below with reference to FIGS. FIG. 1 is a diagram showing a configuration of a signal transmission system according to the first embodiment. In FIG. 1, a signal transmission device includes a time axis compression unit 101 for compressing an audio signal on a time axis.
And a multiplexing unit 102 for multiplexing the video signal and the time-axis-compressed audio signal using the multiplex control signal and transmitting the multiplexed signal to a data line 106 described later as a video / audio multiplexed signal.

The signal receiving device uses the multiplex control signal to
Demultiplexer 1 that separates a video / audio multiplexed signal in which a video signal and an audio signal received via data line 106 are multiplexed.
03, a time axis decompression unit 104 for performing time axis decompression on the audio signal separated by the demultiplexing unit 103 and restoring the original audio signal, and a video clock received via the clock line 107 from the transmission side. And an audio clock reproducing unit 105 for reproducing the audio clock.

The data line 106 is a serial transmission line connecting the signal transmitting device and the signal receiving device. The multiplex control signal is for controlling an audio signal to be multiplexed during an idle time of a video signal such as a horizontal synchronization signal or a vertical synchronization signal of a video signal. No).

Next, the operation of the signal transmission system according to the first embodiment will be described. First, FIG. 2 schematically shows a relationship between a video signal and an audio signal before time-axis compression. In general, a video signal has a larger amount of data than an audio signal, so that one sample of the audio signal substantially corresponds to time in several samples of the video signal. In the signal transmission system according to the first embodiment, this video / audio signal is temporally compressed and multiplexed in an area where no video signal exists. Specifically, the time during which no video signal exists is, for example, a horizontal synchronization period and a vertical synchronization period of the video signal as shown in FIG.
In FIG. 3, a hatched portion other than the effective screen corresponds to the synchronization period. In FIG. 3, an SD screen of MP @ ML (main profile main level) of MPEG2 is taken as an example. The whole screen is 85 horizontally
There are eight pixels and 525 lines vertically. The effective screen among them has 720 horizontal pixels and 480 vertical lines, and the difference between the entire screen and this effective screen is the synchronization period. The audio signal is multiplexed during this synchronization period.

Next, the operation on the transmitting side will be described. FIG. 4 is a diagram showing a configuration of the time axis compression unit 101. The time axis compression unit 101 is mainly configured by a memory, and converts a rate of an input audio signal. Specifically, the input sampling clock is the audio clock fa, and the output clock is the video clock fv. Note that fa is the audio sampling clock frequency, and fv is the video sampling clock frequency. A multiplex control signal is used for output control of the time compression section 101. A horizontal synchronization signal or a vertical synchronization signal is used as the multiplex control signal.

FIG. 5 is a diagram showing a state of time axis compression by the time axis compression section 101. The audio signal before the time axis compression is input at the sampling frequency fa, and the audio signal after the time axis compression is output to the multiplexing unit 102 at the sampling frequency fv. The time-compressed audio signal is output during the LOW period of the multiplex control signal. In this figure,
For simplicity, the number of audio sample points output during the LOW period of the multiplex control signal is shown small,
The number of audio sample points actually output is much more than this.

FIG. 6 is a diagram showing a configuration of the multiplexing unit 102. The multiplexing unit 102 multiplexes the video signal and the time-axis-compressed audio signal and transmits the multiplexed signal as a video / audio multiplexed signal. Switching of the input of the video signal and the audio signal compressed on the time axis to the multiplexing unit 102 is performed by a multiplex control signal. A horizontal synchronization signal or a vertical synchronization signal of an image is used as the multiplex control signal.

FIG. 7 shows how the multiplexing section 102 multiplexes the video signal and the audio signal. In the figure, the video signal and the audio signal after the time axis compression are in the upper two stages. White circles are sample points of video signals, and black circles are sample points of audio signals. The lowermost part shows how the audio signal is multiplexed with the video signal while the multiplex control signal is LOW. Then, this video / audio multiplexed signal becomes a signal on the transmission path and is transmitted to the transmission path.

Next, the operation on the receiving side will be described. FIG. 8 is a diagram illustrating a configuration of the separation unit 103. The separation unit 103 converts the video / audio multiplex signal flowing from the data line 106 into
The video signal and the audio signal compressed on the time axis are separated. Note that a separation control signal is used for separation, and a multiplex control signal provided from a transmission side via a transmission line provided separately from the data line 106 is used as the separation control signal.

FIG. 9 is a diagram showing how the separating unit 103 separates the video signal and the audio signal. Data line 106
The video / audio multiplexed signal flowing from is separated into a video signal and an audio signal by a separation control signal. Specifically, a signal in a period when the separation control signal is LOW is regarded as a time-base-compressed audio signal, and the selector of the separation unit 103 shown in FIG. 8 is set to the audio signal output.

FIG. 10 is a diagram showing the configuration of the time axis extension unit 104. The time axis decompression unit 104 is mainly composed of a memory, and separates a time axis compressed audio signal into a low control signal.
During the period, the video signal is input with the video sampling clock fv and output with the audio sampling clock frequency fa. As a result, an audio signal whose time axis is expanded as before is obtained.

FIG. 11 is a diagram showing how the time expansion unit 104 expands the time axis. The data in the period in which the separation control signal is LOW is regarded as an audio signal, and the time-axis-compressed audio signal is input at the sampling frequency fv only during the period in which the separation control signal is LOW, and is beaten out with the sampling frequency fa to obtain the time. An audio signal whose axis has been extended can be obtained.

Next, the operation of the audio clock reproducing unit 105 will be described. On the receiving side, the audio clock is reproduced by applying a PLL (Phase Lock Loop) based on the video clock sent from the transmitting side, and the audio clock is supplied to the time axis expansion unit 104.

As described above, in the signal transmission system according to the first embodiment of the present invention, the multiplexing unit 102 on the transmitting side multiplexes the video signal and the time-axis-compressed audio signal based on the multiplex control signal. Thus, the video signal and the audio signal can be transmitted on the same data line 106. On the receiving side, the video / audio multiplexed signal received via the data line 106 is separated by the separation control signal, so that the video / audio multiplexed signal can be separated into a video signal and an audio signal.

Further, a horizontal synchronizing signal or a vertical synchronizing signal of a video signal is used as a multiplexing control signal and a demultiplexing control signal.
Further, since the audio signal is compressed on the transmission side on the time axis and expanded on the reception side on the time axis, the audio signal can be multiplexed into the gaps between the video signals and separated.

(Embodiment 2) Hereinafter, a signal transmission system according to Embodiment 2 will be described with reference to FIGS. FIG. 12 is a configuration diagram of a signal transmission system according to the second embodiment. In FIG. 12, a signal transmission device includes a time axis compression unit 201 that compresses a time axis of an audio signal,
The video signal and the audio signal are multiplexed using the multiplex control signal,
It comprises a multiplexing unit 202 that outputs a multiplexed video and audio signal, and a multiplex control signal processing unit 208 that processes a multiplex control signal.

The signal receiving device is provided with a separating unit 203 for separating a video / audio multiplex signal received via the data line 206.
A time axis extending section 204 for extending the time axis of the audio signal separated by the separating section 203;
A data line 206 comprising an audio clock reproducing unit 205 that reproduces an audio clock from a video clock received via a video signal 07 is a transmission line connecting the signal transmitting device and the signal receiving device.

The difference between the signal transmission system according to the second embodiment and the signal transmission system according to the first embodiment is as follows.
In the signal transmission system according to the second embodiment, the multiplex control signal is not notified to the receiving side.

The operation of the signal transmission system according to the second embodiment will be described below. The time axis compression unit 20
In the first embodiment, the time axis compression of the audio signal is performed as in the first embodiment, but the multiplex control signal for the time axis compression is applied to the first embodiment.
And different.

FIG. 13 is a diagram showing the configuration of the time axis compression section 201. The time axis compressing section 201 is configured by a memory similarly to the time axis compressing section 101 of the first embodiment, and converts a sampling rate of an audio signal. In the first embodiment, a multiplex control signal, that is, a horizontal synchronizing signal or a vertical synchronizing signal is used as it is as a control signal of the memory, but in the second embodiment, this signal is slightly processed and used.
Specifically, a signal is used that counts from the falling edge of the multiplex control signal (horizontal synchronization signal or vertical synchronization signal) and falls during the period of the L clock of the video sampling clock (L × 1 / fv sec.). The purpose of this is to provide a non-signal period (L clock period) before the audio signal after the time axis compression, and to recognize this non-signal period as the switching timing of the video signal and the audio signal on the receiving side. is there.

FIG. 14 is a diagram showing a state of time axis compression by the time compression section 201. In this figure, the relationship between the audio signal before time axis compression and the audio signal after time axis compression is almost the same as these relationships in the first embodiment,
The audio signal after the time axis compression with respect to the fall of the multiplex control signal is delayed by L clocks. There is no signal during this L clock period.

FIG. 15 is a diagram showing how a video signal and an audio signal are multiplexed in the second embodiment. As described in FIG. 14, an L-clock non-signal period is provided between the video signal and the audio signal after the time axis compression. In the second embodiment, a sample of a time-axis-compressed audio signal to be multiplexed with a video signal is determined as an M clock period (M × 1 / fv sec.) Of a video sampling clock. L and M are integers and are constant values. The multiplex control signal processing unit 208 generates a new multiplex control signal in which the fall of the multiplex control signal (horizontal synchronization signal or vertical synchronization signal) is delayed by L clocks. By doing so, the receiving side can recognize where the audio signal is and how many sample points are located,
Audio signals can be separated.

FIG. 16 is a diagram showing the configuration of the separation unit 203. In the figure, reference numeral 210 denotes a selector circuit for separating a video signal and a time axis compressed audio signal. A selector control signal generation unit 211 generates a signal for controlling the selector circuit 210. Reference numeral 212 denotes a no-signal detection unit which detects a no-signal state of the video / audio multiplex signal flowing through the transmission path. The counter 213 counts a period during which a sample of the audio signal exists, and is M clock periods (M
× 1 / fv sec. ) Is counted.

Next, a specific operation of the separating section 203 will be described. The no-signal detecting unit 212 outputs an L clock period (L × 1 / f).
v sec. When the no-signal state is detected, the output level is changed from HIGH to LOW. The timing of the count start (fall of the output) of the counter 213 is the same as the fall timing of the output of the no-signal detection unit 212. After counting M clock periods from the fall of the output of the no-signal detection unit 212, the counter 213 raises its output from LOW to HIGH. The selector control signal generator 211 is a circuit that performs an OR operation on the output of the no-signal detector 212 and the output of the counter 213.
The selector circuit 210 includes a selector control signal generation unit 211
When the output of the selector control signal generation unit 211 is LOW, the video signal is extracted by selecting A while the output of the selector control signal generation unit 211 is LOW.

FIG. 17 shows how video signals and audio signals are separated in the second embodiment. In the video / audio multiplexed signal on the transmission line, an audio signal sample exists for M clock periods after a non-signal period lasts for L clock periods. Then, as described with reference to FIG.
If the selector is switched to B during the period of W and set to A during the other periods, the video signal and the audio signal can be separated and extracted from the video / audio multiplexed signal.

FIG. 18 is a diagram showing the configuration of the time axis extension unit 204. The time axis extending section 204 is formed of a memory similarly to the time axis extending section 104 of the first embodiment, but the selector control signal described in FIG. 16 is used as the separation control signal.

FIG. 19 is a diagram showing how the time axis expansion unit 204 expands the time axis. The time-axis-compressed audio signal is converted to a separation control signal, that is, a selector control signal LOW.
The time axis extending unit 20 at the sampling frequency fv during the period
4 and beats it out with an audio sampling clock fa to obtain an audio signal whose time base is expanded.

As described above, in the signal transmission system according to the second embodiment, the same operation as the signal transmission system according to the first embodiment can be realized without transmitting a multiplex control signal to the receiving side. That is, in the second embodiment, in a period in which a video signal and an audio signal are multiplexed, a signal state of an L clock period is provided between the video signal and the audio signal,
Also, the sampling point of the audio signal is fixed as the M clock period, and the receiving side detects the non-signal period during the L clock period, and then considers the M clock period as the separation timing of the audio signal. The audio signal and the video signal can be separated without transmitting to the receiving side.

(Embodiment 3) A signal transmission system according to Embodiment 3 will be described below with reference to FIGS. The third embodiment is different from the first and second embodiments.
Of DVI (Digital Visual Int.)
erface) applied to the standard.

FIG. 20 is a diagram showing a configuration of a signal transmission system according to the third embodiment. In FIG. 20, 301
Is a time axis compression unit, which is the same as that used in the first or second embodiment. Reference numeral 302 denotes a decomposing unit, which converts the time-axis-compressed audio signal into CTL2 and CTL according to the DVI standard.
3, which is decomposed and superimposed on the signal of CTL1. 3
03 to 305 are TMDS encoder / serializer, 3
06 to 308 are TMDS decoders / recoveries;
These are the same as those described in the prior art. 3
Reference numeral 09 denotes a synthesizing unit that synthesizes audio signals from the CTLs 1, 2, and 3. Reference numeral 310 denotes a time-axis decompression unit that decompresses the time-axis-compressed audio signal output from the synthesis unit 309. In this figure, the channel 0 of the transmission path has BLUE and HSYN of the video signal.
C, VSYNC (horizontal synchronization signal, vertical synchronization signal) time-division multiplexed serial data is transmitted, and channel 1
, Serial data in which GREEN and voice (CTL1) are time-division multiplexed is transmitted.
Serial data in which the ED and voice (CTL2, 3) are time-division multiplexed is transmitted.

The operation of the signal transmission system configured as described above will be described. FIG. 21 shows a state of a signal on a transmission line according to the third embodiment. First, TMD on top
4 shows data of an input to the S encoder. A CTL (control signal) is inserted while the DE (data enable) signal is LOW, and a time-axis-compressed audio signal is placed on these CTLs 1, 2, 3 to perform TMDS encoding. Then, in the signal on the transmission path, CTLs 2 and 3 encoded on channel 2 are superimposed, and CTL 1 encoded on channel 1 is superimposed. Thus, on the transmission line, audio (sound signal) is superimposed during the period of the horizontal synchronization signal or the vertical synchronization signal. The data at the bottom is TMDS decoded and recovered on the receiving side. The recovered data is exactly the same as the input data on the transmission side.

Next, a method of separating the sound on the receiving side will be described. As shown in FIG. 22, first, a fixed period of data of channel 0 is detected by a fixed data period detection circuit 350. The certain period of the data is a horizontal synchronization period or a vertical synchronization period. A fixed period of the data is detected and a DE (data enable) signal is generated and transmitted. A period in which the DE signal is LOW is regarded as a period in which the audio signal is multiplexed. D for separation circuits 351 and 352
The E signal is supplied, and the video signal and the audio signal are separated by the channel 1 and channel 2 decoders. And CTL1,
The separated audio signals of the lines CTL2 and CTL3 appear.

Next, a decoding method on the receiving side will be described. In FIG. 23, a video / audio multiplex signal transmitted to channel 2 is converted into a serial / parallel converter 36.
The serial / parallel conversion is performed at 0 and the period when the DE (data enable) signal is HIGH is regarded as a video signal, and the decoder 362 performs 10-bit / 8-bit TMDS decoding, thereby obtaining a RED signal. A period in which the DE (data enable) signal is LOW is regarded as an audio signal, and the decoder 363 outputs 10 bits / bit.
Performs 2-bit TMDS decoding and performs CTL2, CTL3
The audio signal can be obtained on the line. Similarly, the video / audio multiplexed signal transmitted in channel 1 is converted from serial / parallel by a serial / parallel conversion circuit 361, and when the DE (data enable) signal is HIGH, it is regarded as a GREEN video signal. Performs a bit / 8-bit TMDS decoding. Then, when the DE (data enable) signal is LOW, the decoder 365 performs 10-bit / 2-bit TMDS decoding by the decoder 365 to obtain an audio signal on the CTL1.

Thus, CTL (control)
The audio signal obtained on the line is synthesized by the synthesizing unit 309, and further subjected to rate conversion by the time axis decompression unit 310, whereby the original audio signal can be obtained.

Next, the operation of the decomposing unit 302 and the synthesizing unit 309 will be described. The decomposing unit 302 decomposes the time-axis-compressed audio signal into three CTLs 2, 3 and 1. Depending on the band of the audio signal, only one CTL2 or two CTLs 2 and 3 may be used. You can also use it. In addition, according to the order of the sampling points of the audio signal, the signal may be decomposed in the order of CTLs 2, 3, 1, 2, 3, and 1. The combining unit 309 decodes the audio signal flowing from the transmission path,
Assuming that the audio signal is coming in the order of 3, 1
What is necessary is just to synthesize. Note that these three lines may be used in an arbitrary order instead of the order of the CTLs 2, 3, and 1. However, the order of the disassembly and the combination must be determined between the transmitting side and the receiving side.

As described above, in the signal transmission system according to the third embodiment, the configuration of the signal transmission system according to the first and second embodiments is applied to the DVI standard, and the signal obtained by compressing the audio signal on the time axis is CTL2,3,1. And the receiving side synthesizes the audio signals transmitted by the CTLs 2, 3, and 1 and expands the time axis to restore the audio signals. In a signal transmission system, transmission of an audio signal can also be enabled.

(Embodiment 4) A signal transmission system according to Embodiment 4 will be described below with reference to FIGS. The fourth embodiment is the first to third embodiments.
Unlike the case where the audio signal is not transmitted using the gap between the video signals, one of the three transmission lines used in the DVI standard signal transmission system is reserved as the transmission line for the audio signal. It was made. That is, in the DVI standard, the transmission of the video signal is RED, GRE
Although this is performed using component signals such as EN and BLUE, in the fourth embodiment, Y such as Y, Pb, and Pr is used.
A mode for transmitting a color difference signal is added, and an empty channel is assigned to an audio signal there.

FIG. 24 is a diagram showing a configuration of a signal transmission system according to the fourth embodiment. In the figure, reference numeral 401 denotes a selector, which selects a RED signal and a luminance signal (Y) and supplies them to a TMDS encoder. A selector 402 selects a GREEN signal and a Pb or Pr signal. 403 is a selector, and BLU
Either the E signal or the audio signal is selected. Reference numerals 404 to 406 denote TMDS encoders / serializers, and reference numerals 407 to 409 denote TMDS decoders / recoveries. These configurations are the same as those of the first, second, and third embodiments.

A feature of the fourth embodiment resides in that Y-color difference transmission is used for transmitting a video signal. In the Y color difference transmission, there is, for example, 4: 2: 0 transmission. 4:
In the 2: 0 transmission, as shown in FIG. 25, the rate of the chrominance signal is reduced to half the rate of the luminance signal. Specifically, the sampling number of the chrominance signal is halved with respect to the luminance signal. This makes it possible to transmit a video signal using two channels on the DVI transmission path. More specifically, the luminance signal is used for channel 2 and the color signal P is used for channel 1.
b, Pr signals are transmitted. Then, an audio signal is superimposed on the vacant channel 0. This audio signal is an original audio signal that has not been compressed on the time axis.

As described above, in the signal transmission system according to the fourth embodiment, a mode for transmitting a Y color difference signal such as Y, Pb, and Pr is added, and an empty channel is assigned to an audio signal. A signal transmission system conforming to the DVI standard capable of transmitting an audio signal together with a signal can be realized.

In the fourth embodiment, Y, Pb / P
Although r and audio are assigned to channel 2, channel 1 and channel 0, respectively, the order of assignment is not limited to this.

In the embodiment of the present invention, multiplexing and transmission of signals are performed by the multiplexing unit, but multiplexing and transmission may be performed separately.

[0060]

According to the signal transmitting apparatus of the first aspect of the present invention, in the signal transmitting apparatus connected to the signal receiving apparatus via the transmission path, the time axis compression of the first signal is performed on the time axis. Means, a multiplex control signal generator for generating a multiplex control signal based on the second signal, and the time-axis-compressed first signal using the multiplex control signal generated by the multiplex control signal generator. Signal multiplexing means for multiplexing the second signal and the third signal and outputting the multiplexed signal as a multiplexed signal, and signal transmitting means for transmitting the multiplexed signal and the multiplexed control signal to the signal receiving device. Thus, it is possible to realize a signal transmission system that transmits the first, second, and third signals through the same transmission path.

According to the signal transmitting apparatus of the present invention, in the signal transmitting apparatus connected to the signal receiving apparatus via the transmission path, the time axis compressing means for compressing the first signal on the time axis is provided. A multiplex control signal generator for generating a multiplex control signal based on the second signal, the first signal compressed on the time axis using the multiplex control signal generated by the multiplex control signal generator, Signal multiplexing means for multiplexing the second signal and the third signal and outputting the multiplexed signal;
Signal transmission means for transmitting the multiplexed signal to the signal receiving device, thereby transmitting the first, second, and third signals to the same transmission line without transmitting the multiplexed control signal to the signal receiving device. Thus, it is possible to realize a signal transmission system for transmitting the signals.

According to the signal transmitting device of the third aspect of the present invention, in the signal transmitting device of the first or second aspect, the first signal is a voice signal and the second signal is a voice signal.
Is a horizontal synchronizing signal or a vertical synchronizing signal, and the third signal is a video signal. Therefore, a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal can be realized.

According to the signal transmitting apparatus of the fourth aspect of the present invention, in the signal transmitting apparatus of the DVI transmission standard for transmitting an RGB video signal as serial data,
In addition to the first mode for transmitting the video signal of B as serial data, there is a second mode for transmitting three signals of a luminance signal, a color difference signal, and an audio signal, wherein the first mode and the second mode are transmitted. Is provided with a switching means for switching between the modes, so that the audio signal can be transmitted together with the video signal.
A signal transmission system of the VI standard can be realized.

According to the signal receiving apparatus of the fifth aspect of the present invention, in the signal receiving apparatus connected to the signal transmitting apparatus via the transmission path, the signal transmitting apparatus transmits the first time-multiplexed first signal. First receiving means for receiving a multiplexed signal obtained by multiplexing a signal, a second signal, and a third signal; second receiving means for receiving a multiplexed control signal from the signal transmitting device; A separating unit that separates the multiplexed signal received by the first receiving unit into the first and second signals by using the multiplex control signal received by the receiving unit; And a time axis extending unit for extending the first signal on the time axis. Thus, it is possible to realize a signal transmission system capable of transmitting the first, second, and third signals through the same transmission path.

According to the signal receiving apparatus of the sixth aspect of the present invention, in the signal receiving apparatus connected to the signal transmitting apparatus via the transmission path, the signal transmitting apparatus transmits the first time-multiplexed first signal. Receiving means for receiving a multiplexed signal obtained by multiplexing the signal, the second signal, and the third signal; detecting means for detecting the second signal from the multiplexed signal; A multiplex control signal generating means for generating a multiplex control signal based on the second signal; a separating means for separating the multiplex signal into the first, second, and third signals using the multiplex control signal; A time axis extending unit for extending the first signal separated by the separating unit on a time axis, the multiplexed signal can be separated without receiving the multiplexed control signal from the signal transmitting device; The first, second and third signals are It is possible to realize a signal transmission system that can be received by the transmission path.

According to the signal receiving apparatus of the seventh aspect of the present invention, in the signal receiving apparatus of the fifth or sixth aspect, the first signal is an audio signal and the second signal is an audio signal.
Is a horizontal synchronizing signal or a vertical synchronizing signal, and the third signal is a video signal. Therefore, a DVI standard signal transmission system capable of transmitting an audio signal together with a video signal can be realized.

According to the signal receiving apparatus of the present invention, in the signal receiving apparatus of the DVI transmission standard for receiving RGB video signals as serial data,
In addition to the first mode for receiving the video signal of B as serial data, there is a second mode for receiving three signals of a luminance signal, a color difference signal, and an audio signal. Is provided with a switching means for switching between the modes, so that the audio signal can be transmitted together with the video signal.
A signal transmission system of the VI standard can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a signal transmission system according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a video signal and an audio signal before time axis compression.

FIG. 3 is a diagram for explaining a horizontal synchronization period and a vertical synchronization period.

FIG. 4 is a diagram illustrating a configuration of a time axis compression unit of the signal transmission system according to the first embodiment.

FIG. 5 is a diagram for explaining time axis compression in the signal transmission system according to the first embodiment.

FIG. 6 is a diagram showing a configuration of a multiplexing unit of the signal transmission system according to the first embodiment.

FIG. 7 is a diagram showing how a video signal and an audio signal are multiplexed in the signal transmission system according to the first embodiment.

FIG. 8 is a diagram illustrating a configuration of a separation unit of the signal transmission system according to the first embodiment.

FIG. 9 is a diagram showing a state of separation of a video signal and an audio signal in the signal transmission system according to the first embodiment.

FIG. 10 is a diagram showing a configuration of a time axis extension unit of the signal transmission system according to the first embodiment.

FIG. 11 is a diagram for explaining time base expansion in the signal transmission system according to the first embodiment.

FIG. 12 is a diagram showing a configuration of a signal transmission system according to a second embodiment.

FIG. 13 is a diagram illustrating a configuration of a time axis compression unit of the signal transmission system according to the second embodiment.

FIG. 14 is a diagram for explaining time axis compression in the signal transmission system according to the second embodiment.

FIG. 15 is a diagram showing how a video signal and an audio signal are multiplexed in the signal transmission system according to the second embodiment.

FIG. 16 is a diagram illustrating a configuration of a separation unit of the signal transmission system according to the second embodiment.

FIG. 17 is a diagram showing a state of separation of a video signal and an audio signal in the signal transmission system according to the second embodiment.

FIG. 18 is a diagram illustrating a configuration of a time axis extension unit of the signal transmission system according to the second embodiment.

FIG. 19 is a diagram for explaining time base expansion in the signal transmission system according to the second embodiment.

FIG. 20 is a diagram showing a configuration of a signal transmission system according to a third embodiment.

FIG. 21 is a diagram illustrating a state of data in the signal transmission system according to the third embodiment.

FIG. 22 is a diagram illustrating a method of audio separation on the receiving side in the signal transmission system according to the third embodiment.

FIG. 23 is a diagram illustrating a decoding method on the receiving side in the signal transmission system according to the third embodiment.

FIG. 24 is a diagram showing a configuration of a signal transmission system according to a fourth embodiment.

FIG. 25 is a diagram illustrating a signal image on a transmission line in a signal transmission system according to a fourth embodiment.

FIG. 26 is a diagram illustrating a configuration of a conventional signal transmission system.

[Explanation of symbols]

 101, 201 time axis compression section 102, 202 multiplexing section 103, 203 separation section 104, 204 time axis expansion section 105, 205 audio clock reproduction section 106, 206 data line 107, 207 clock line 208 multiplex control signal processing section 210 selector circuit 211 selector control signal generation section 212 no signal detection section 213 counter 301 time axis compression section 302 decomposition section 303 to 305 TMDS encoder / serializer 306 to 308 TMDS decoder / recovery 309 synthesis section 310 time axis expansion section 401 to 403 selector 404 to 406 TMDS encoder / serializer 407-409 TMDS decoder / recovery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 11/00 11/24 F term (Reference) 5C057 AA03 BA15 DA02 DB01 EA01 EA02 EC01 EC04 EL01 FA03 FC10 GB02 5C063 AA01 AB03 AC01 AC05 CA14 CA20 DA07 DB05 5D045 BA02 5K028 AA08 AA11 BB01 EE03 KK01 KK03

Claims (8)

[Claims] 1. A signal transmitting device connected to a signal receiving device via a transmission line, a time axis compressing means for compressing a first signal on a time axis, and a multiplex control signal based on the second signal. Multiplexing the time-axis-compressed first signal, the second signal, and the third signal using a multiplex control signal generator and a multiplex control signal generated by the multiplex control signal generator; A signal transmitting device comprising: a signal multiplexing unit that outputs a multiplexed signal; and a signal transmitting unit that transmits the multiplexed signal and the multiplexed control signal to the signal receiving device. 2. A signal transmitting device connected to a signal receiving device via a transmission line, wherein a time axis compressing means for compressing a first signal on a time axis and a multiplex control signal are generated based on the second signal. Multiplexing the time-axis-compressed first signal, the second signal, and the third signal using a multiplex control signal generator and a multiplex control signal generated by the multiplex control signal generator; A signal transmitting device comprising: a signal multiplexing unit that outputs a multiplexed signal; and a signal transmitting unit that transmits the multiplexed signal to the signal receiving device. 3. The signal transmission device according to claim 1, wherein the first signal is an audio signal, the second signal is a horizontal synchronization signal or a vertical synchronization signal, and the third signal is The signal transmitting device is a video signal. 4. A signal transmission device according to the DVI transmission standard for transmitting an RGB video signal as serial data, wherein a luminance signal, a color difference signal, and an audio signal are transmitted in addition to the first mode for transmitting the RGB video signal as serial data. A signal transmission device, comprising: a second mode for transmitting three signals of signals; and switching means for switching between the first mode and the second mode. 5. A signal receiving apparatus connected to a signal transmitting apparatus via a transmission path, wherein the signal transmitting apparatus transmits a time-division multiplexed first signal;
First receiving means for receiving a multiplexed signal in which the second signal and the third signal are multiplexed; second receiving means for receiving a multiplexed control signal from the signal transmitting device; Separating means for separating the multiplexed signal received by the first receiving means into the first and second signals by using the multiplex control signal received by the means; 1. A signal receiving apparatus, comprising: a time axis extending unit that extends the time axis of one signal. 6. A signal receiving device connected to a signal transmitting device via a transmission path, wherein the signal transmitting device outputs a first signal multiplexed on a time axis,
Receiving means for receiving a multiplexed signal in which a second signal and a third signal are multiplexed; detecting means for detecting the second signal from the multiplexed signal; and a second signal detected by the detecting means Multiplex control signal generating means for generating a multiplex control signal based on the multiplex control signal,
A signal receiving apparatus, comprising: separating means for separating into second and third signals; and time axis extending means for extending the first signal separated by the separating means on a time axis. 7. The signal receiving apparatus according to claim 5, wherein the first signal is an audio signal, the second signal is a horizontal synchronizing signal or a vertical synchronizing signal, and the third signal is The signal receiving device is a video signal. 8. A signal receiving apparatus according to a DVI transmission standard for receiving RGB video signals as serial data, further comprising a luminance signal, a color difference signal, and an audio signal in addition to the first mode for receiving the RGB video signals as serial data. A signal receiving apparatus comprising: a second mode for receiving three signals; and a switching unit configured to switch between the first mode and the second mode.