DE4441517A1 - Device for transmitting and receiving for a video signal with compressed audio signals - Google Patents

Abstract

A system for transmitting composite television signals composed of a compressed time base of an audio signal injected into a composite video signal during the vertical blanking interval, for transmission through a common transmission line. Fig. 4 shows a compressed audio signal with a video signal. <IMAGE>

Description

The present invention relates to a device for Received and on a device for transmitting television si signals that have a video signal and audio signal.

More specifically, the invention relates to a transmission and emp Catching system for video signals that are turned on with an audio signal be fed, and more precisely it refers to a transfer supply and receiving device for video signals with a fed audio signal whose time base is compressed.

In a surveillance television system such as an operational or induction The video signal and the audio signal become the distribution network transmitted separately. That is why such a system makes dual or double transmission lines for the video signal and for the audio signals needed, which is expensive. Beyond that In such a system, the receiving device or the emp fall arrest device provided twice and for large surveillance tasks complex, since separate selection and reception devices must be used for video and audio channels.

There is a system for multiplexing a carrier whose frequency is modulated by an audio signal, on the video signal and  Transmission of the audio-video multiplex signal over a single one Transmission line. However, the Trä signal frequency is outside the video frequency bandwidth, and moreover, the signal level must be minimal, in order not to Bring noise into the video signal.

This includes a transmission line with a large bandwidth and emp high-gain circuits necessary and this ver causes crosstalk between channels of the receiving device tung.

There is another system for transmitting an image signal and an audio signal over a common transmission line, the different carrier waves as in the case of television broadcasting ver turns. However, in such a system, both the over Carrier device and the receiving device complicated and expensive.

It is an object of the present invention to transmit Audio and video signals over a common transmission line to enable without any influence on an audio signal the video signal or a video signal to the audio signal to practice.

This object is achieved by a device for transmission of television signals according to claim i and a device for emp capturing television signals according to claim 17.

Developments of the invention are specified in the subclaims ben.

A device for transmitting television signals after a Embodiment of the present invention has a compression tion device for compressing (shortening) the time base of a Audio signal, an insertion device for inserting the kompri mated audio signal into the video signal during the vertical Blanking period of the video signal and a composition direction for transmitting the video signals with the compressed Audio signal on.  

A device for receiving television signals after a Embodiment of the present invention receives one together set video signal, the compressed audio signals used more precisely an audio signal whose time base is compressed and that during the vertical blanking period of the composite Video signal is inserted, and the receiving device assigns an extraction and restoration facility Extract the compressed audio signal from the received one composite signal and to restore the (originally Lichen) time base of the extracted (compressed) audio signal on.

Since the time base of the audio signal is compressed and the kompri mated audio signal during the vertical blanking period of the composite video signal is inserted into the video signal can the audio signal over a video transmission line without off exercise any influence on the transmitted image of the together set video signal are transmitted.

The compression device preferably has an analog Digital conversion circuit for converting the audio signal that is to be transferred into a digital signal, a memory for Save the output from the analog-to-digital conversion circuit given digital signal, a control circuit for controlling the Writing the digital signal into the memory and for control reading the signal from the memory and outputting the signal stored in memory at a rate which are faster than the write speed of the signal in the Is memory, and a digital-to-analog conversion circuit for Convert the digital signal read from the memory back into an analog signal. This can change the time base of the audio signals are effectively compressed (i.e. the duration is shortened), while the continuous audio signals were screaming into memory be.

The assembly device of the transmission device has preferably an output signal switching circuit on the by the control circuit for alternating switching of the composite audio signal from the video signal to the kompri  mated audio signal is controlled. This will make the Videosi gnal and the audio signal sequentially, d. H. in sections consecutively transmitted and have no interaction other out.

When the transmitted audio signal has a first and a second Au diosignal such as for a stereo sound transmission the compression device instructs the transmission direction preferably an analog-to-digital conversion scarf device with a first and a second A-D converter, wherein the first A-D converter converts the first audio signal into a digital Si gnal converts and the second A-D converter in the second audio signal converts a digital signal. The facility also has one Memory for storing the from the first and the second A-D Output digital signals converter, a control circuit for Control the writing of digital signals to memory and reading the signal from the memory and outputting the signal stored in memory at a rate which are faster than the write speed of the signal in the Memory is a digital-to-analog conversion circuit for converting the digital signal read from the memory back into an analog signal, and a signal composition section to assemble the output signals of the two D-A converters. This allows the first and second audio signals for the Ste reoklang over a common transmission line, which for the Video signal is used without exerting any influence ses on the image of the video signal or a mutual change effect are transferred.

In addition, when the transmitted audio signal is a first and a second audio signal like a stereo sound transmission has, the compression device of the transmission device device further an audio signal switching circuit for alternating Switching the first and the second audio signal and the Ausge ben same to the analog-to-digital conversion circuit sen. This allows the first and second audio signals for Ste reoklang over a common transmission line, which for the Video signal is used without exerting any influence  on the picture of the video signal and without a mutual change effect are transferred.

The assembly device of the transmission device has further preferably a first clamping circuit for clamping the video signals (i.e. the base level of the video signal) that the signal Alternating circuit is to be supplied on a predetermined span voltage level and a second clamping circuit for clamping an off output signals (i.e., the base level of the output signal) of the Digi tal-analog conversion circuit that the signal change circuit is to be supplied at the same predetermined voltage level that the video signal is set to. This allows both the audio signal as well as the video signal, both on the same Level (basic level) are clamped or held, alternating can be carried over a common transmission line without (for example due to large voltage jumps) to act.

The compression device preferably compresses the Transmission device the time base of the audio signal with a Rate (i.e., in degrees) that is a time that is vertical Blanking period of the video signal corresponds to one time which corresponds to a horizontal blanking period of the video signal speaks, and the assembly means of the transmission direction injects or sets the compressed audio signal a single horizontal line period during the vertical Blanking period of the video signal. This allows the audio signal do not disturb or influence the image of the video signal.

The compression device of the transmission device in egg A preferred embodiment has an analog-to-digital conversion circuit for converting the audio signal to be transmitted is, in a digital signal, a memory for storing the output digital signals, a control circuit for control and coordinating the timing and speed of the Write the signals in the memory and the time and the Speed of reading the signals from the memory, so that the signal read from the memory of the written Signal is compressed and every vertical sampling period output  ben, and so during a vertical scan period written audio signal during a horizontal scanning period is read out, whereby the compression ratio is equal to Vertical scan period divided by time horizontal scanning period. The compression device of the Transmission device also has a digital-to-analog conversion circuit for converting the read out from the memory compressed signal into an analog signal, the Zu composition device of the transmission device preferred an output signal of the digital-to-analog conversion circuit into a horizontal scanning period during the ver tical blanking period of the video signal.

Instead of inserting the compressed signal into the video gnal can be the composition device of the transmission direction an output signal changeover circuit for switching the Output signal alternating between the Digi output signal tal-analog conversion circuit and the video signal and off give the compressed audio signal during a horizontal Sampling period within each vertical blanking period of Vi have deodorant signal.

The extraction and restoration facility of the Emp The catching device preferably has an extraction scarf device or separation circuit for extracting the compressed ana Lied audio signal, an analog-to-digital conversion circuit for Convert the compressed and from the extraction circuit extracted audio signal into a digital signal, a memory for storing the from the analog-to-digital conversion circuit output digital signal, a control circuit for control the timing and speed of writing the Si gnals in the memory and the time and speed reading the signal from the memory and outputting the signals stored in the memory with a slower Ge speed with the reciprocal of the writing speed of the Signals in the memory and a digital-to-analog conversion scarf device for converting the signal read from the memory into an analog signal. This will make the audio signal whose Time base is compressed, back into a continuous audiosi  gnal, whose time base is restored, regenerates or it is generated again.

If the received audio signal is an alternating compressed Stereo signal consisting of a first and a second audio signal, instructs the digital-to-analog conversion circuit of reception direction preferably a first D-A converter for conversion the first audio signal into an analog signal and a second D-A converter for converting the second audio signal into an analog signal. This allows the first and second audiosi signal for stereo sound without affecting the image signal or a mutual influence of the audio signals regenerates or be restored.

If the stereo audio signal is an alternating combined Si gnal from the first and the second audio signal, the Extraction and recovery facility of the reception direction a first sample-hold circuit for extraction and holding the first audio signal from the digital-to-analog conversion tion circuit and a second sample and hold circuit for extra Here and hold the second audio signal from the digital Ana have log conversion circuit. This allows the first and the second audio signal for stereo sound without affecting the Image signals or a mutual influence regenerated become.

The extraction and restoration facility of the Emp catching device preferably also has a holding or Clamping circuit for clamping the analog-digital conversion circuit to be supplied signal on a predetermined span level, making the received audio signals accurate or can be converted exactly into digital signals.

The extraction and restoration facility for the Emp Catcher preferably further has audio bandpass fil to remove any video signal components from the Output signals of the digital-to-analog conversion circuit. There can regenerate or restore the audio signal without being affected by the video signal.  

If the time base of the audio signal in the composite Si gnal is compressed with a degree that is a time (duration in the original audio signal) that a vertical sampling period ode of the video signal corresponds to a time (duration in the compressed signal), which is a horizontal scan period of the video signal corresponds to the extraction and Recovery device of the receiving device preferred the time base of the extracted audio signal with a Rate again that a time (length of time in the compressed Signal) representing a horizontal sampling period of the video signal corresponds to a time (time period in the restored th signal), which is equal to a vertical sampling period of the Video signal is. This allows the audio signal to be restored exactly be put.

If the compressed audio signal is in a specific horizontal Line during the vertical blanking period or the vertical Blanking period of the video signal is inserted, which extracts Extraction and recovery facility of the reception direction of the audio signal from the composite signal preferably by pulling out or separating the synchronizer tion signal from the composite video signal for application of the extracted synchronization pulses to the controller and to the timing circuit for extracting the compressed Video signal from the composite video signal and for input ben of the extracted signal in the D-A conversion circuit during the specific horizontal line period. This can the audio signal can be precisely extracted and restored.

Further features and advantages of the invention result from the description of exemplary embodiments with reference to the Characters.

From the figures show:

Fig. 1 is a block diagram showing an electrical circuit device of a transmission device as an embodiment of the present invention;

Fig. 2 is a view showing the waveform of an electrical signal in the transmission device shown in Fig. 1;

Fig. 3 is a block diagram showing an electrical circuit of a receiving device for separating egg nes signal composed by the transmission device shown in Fig. 1 into a video signal and an audio signal as an embodiment of the present invention;

Fig. 4 is a block diagram showing an electrical circuit device of a transmission device of another embodiment;

Fig. 5 is a block diagram showing an electrical circuit device of a transmission device of another embodiment;

Fig. 6 is a block diagram showing an electrical circuit device of a transmission device according to yet another embodiment;

Fig. 7 is a block diagram of an electrical circuit of a transmission device according to a yet another embodiment;

Fig. 8 is a view showing the waveform of an electrical rule signal is generated by the transmission means, which are shown in Figures 4, 5, 6 and 7.

Fig. 9 is a block diagram showing an electrical circuit of a receiving device for separating egg nes by any of the transmission means shown in Figs. 4, 5 and 7 composite signal into a video signal and an audio signal as an embodiment of the present invention; and

Fig. 10 is a block diagram showing an electrical circuit of a receiving device for separating egg nes signal composed by the transmission device shown in Fig. 6 into a video signal and an audio signal as an embodiment of the present invention.

As shown in FIG. 1, a transmission device 10 is a composing device for composing a video signal and an audio signal.

In the transmission device or circuit 10 , a video signal from a video signal generator such as a television camera or a video player is input into a connector 12 , while an audio signal from an audio signal generator such as a microphone or a video player is input into a connector 14 .

In the illustrated embodiment, the video signal input to terminal 12 is a known composite video signal that is supplied to a clamp circuit 16 and a synchronization isolation circuit 18 . The synchronization separation circuit 18 extracts the horizontal synchronization signal and the vertical synchronization signal from the video signal, and supplies the extracted signals to a timing controller 20 . The controller 20 generates various timing signals based on the synchronization signals supplied from the synchronization disconnection circuit 18 .

The audio signal that is input to the terminal 14 is an analog signal that was successively by a controllable cons stand or a volume control 22 and an amplifier 24 runs and then input to an analog-to-digital conversion circuit 26 . The analog-to-digital conversion circuit (AD converter) 26 is activated based on the timing signal supplied from the controller 20 with a predetermined period and converts the analog audio signal into a digital signal during the active period.

The output signal of the AD converter 26 is given to a memory 28 . The memory 28 is also input with the write timing signal from the controller 20 for controlling the write speed, and therefore the memory 28 successively writes the signal input from the AD converter 26 . The timing control 20 also leads the memory 28 to the readout timing signal, so that the signal written in the memory 28 is read out at a greater speed than the write speed.

The readout speed of the signal from the memory 28 preferably speaks to such a speed that a period corresponding to a vertical scanning period of the video signal is equal to a time corresponding to a horizontal scanning period. Otherwise, any other speed can be adapted to the readout speed. The readout timing of the signal from memory 28 corresponds to a horizontal scan period of a video signal, preferably within the vertical blanking period, and more preferably is a horizontal scan line period during the vertical blanking period.

The memory 28 may be provided with a plurality of memory sections for successively storing audio signals, which are equal to a time period which corresponds to at least one vertical sampling period of the video signal, so that such a memory arrangement allows a simple circular response of the memory sections for successive writing of the Signal and for subsequent reading of the signal with each vertical sampling of the video signal, he enables.

The signal read out from the memory 28 is converted by a digital-to-analog conversion circuit (DA converter) 30 into an analog signal. The DA converter 30, a Zeitsteue is further approximate signal supplied by the timing controller 20 so that the digital-to-analog conversion of the signal supplied from the memory 28 Si gnals carried out in synchronization with the readout of the signal from the memory 28th

The frequency of an audio signal shown in Fig. 2 (A) is compressed n times in Fig. 2 (B), where n is the ratio of a vertical sampling period 1 V of a video signal divided by a time equal to a horizontal sampling period 1 H of the video signal corresponds to that shown in Fig. 2 (B), and in the case of the NTSC system, n can be defined as the number of horizontal scanning lines per field (field), that is, approximately 262.5. As a result, the audio signal is compressed in a timely manner, namely the time base of the audio signal is compressed in 1 / n, where the frequency of the compressed audio signal increases n times. The compressed audio signal is output from the DA converter 30 during the vertical blanking period of the video signal 1 Bv shown in FIG. 2 (C), preferably during a specific horizontal sampling period 1 H within the vertical blanking period 1 Bv shown in FIG. 2 (D) is shown.

An output signal of the DA converter 30 is input to a clamp circuit 32 , and the circuit 32 is also supplied with a timing signal from the controller 20 . Based on the timing signal supplied from the controller 20 , the latch circuit 32 holds the signal output from the DA converter 30 at a predetermined voltage level for a period of time corresponding to a feeding period (injection period) of the compressed audio signal into the video signal speaks, that is, preferably during the 1H period of the 1Bv period shown in Fig. 2 (D).

The supplied from the controller 20 of the holding circuit 32 timing signal supplied from the control circuit 20 also a holding sixteenth Based on the timing signal supplied from the controller 20 , the hold circuit 16 holds the video signal supplied from the terminal 12 at a predetermined voltage level during the remaining vertical scanning period 1 V shown in Fig. 2 (D).

The audio signal, the signal components of which are present during the 1H period from FIGS . 2 (B) and 2 (D), is supplied from the hold circuit 32 to a signal input of a signal change circuit 34 , and a video signal which is shown in FIG 2 (C) is shown., is from the latch circuit 16 to the other Si gnaleingangsanschluß the signal switching circuit 34 is supplied.

The timing signals supplied to the latch circuits 16 and 32 from the controller 20 are also supplied to the signal change circuit 34 for controlling the signal change timing. The signal switching circuit 34 is an electronic switching circuit which switches either the compressed audio signal during the horizontal scanning period 1 H shown in FIG. 2 (B) or the video signal during the rest of the vertical scanning period 1 V shown in FIG. 2 (C) is output to a terminal 36 . Since both signals, the compressed audio signal and the video signal are clamped or held at the same predetermined level by the clamping circuits 16 and 32 , a very smooth transition can be achieved during switching by the electronic switch of the signal change circuit 34 . As a result, a jump-free composite signal shown in Fig. 2 (D) is output at the terminal 36 .

In the transmission device 10 , each of the circuits 18 , 20 , 26 , 28 and 30 operates as an element of a compression device for compressing the time base of an audio signal. In addition, each of the latch circuits 16 , 32 and the signal change circuit 34 functions as an element of a composing device for composing the compressed audio signal and a video signal. In addition, the timing controller 20 functions as a control circuit for controlling the circuits 16 , 26 , 28 , 30 , 32 and 34 in the transmission device 10 together with the synchronization disconnection circuit 18 . If the video signal source is a video camera that includes a synchronization generator and if the transmission device 10 is connected to the video camera, the synchronization signals can be transmitted or driven directly from the video camera and the synchronization disconnection circuit 18 is unnecessary.

The timing signals are supplied from the timing controller 20 to each of the circuits 16 , 26 , 28 , 30 , 32 , 34 and 36 and are mutually related to have a predetermined phase relationship with each other and with a video signal. Such a phase relationship can be obtained by generating various timing signals based on the synchronization signals output from the synchronization isolation circuit 18 .

As shown in Fig. 3, a receiving device or a receiving device 40 separates the audio signal from a composite signal consisting of a video signal with a compressed audio signal fed in, and restores the original audio signal, ie it restores the audio signal.

The receiving device 40 receives a composite signal from the transmission device 10 shown in FIG. 1 via a connection 42 . The composite signal is inputted to a synchronization separation circuit 44 and the latch circuit 48 .

The synchronization separation circuit 44 separates the horizontal and the vertical synchronization signals from the composite signal and supplies the separated synchronization signals to a timing controller 50 . The timing controller 50 he witnesses various timing signals on the basis of the Syn chronisationssignale, which are supplied from the tung 44 Synchronisationsabtrennschal. The timing signals generated by controller 50 are input to latch 48 , AD converter 54 , memory 56 and DA converter 58 .

Based on the timing signals supplied from the controller 50 , the latch 48 holds the composite signal supplied from the terminal 42 at a predetermined voltage level during the time in FIG. 2 (D) 1 H period shown, ie during the time in which the compressed audio signal is fed into the video signal. As a result, the audio signal components in the composite video signal are held or clamped at a predetermined voltage level.

An output signal of the clamp circuit 48 is input to the analog-digital conversion circuit 54 .

The AD converter 54 converts the audio signal output from the clamp circuit 48 into a digital signal during the 1 H period shown in FIG. 2 (D) based on the timing signal supplied for conversion from the controller 50 .

The signal converted in the AD converter 54 is input to a memory 56 and written into the memory based on a write timing signal supplied from the controller 50 . The memory 56 successively writes in the signal supplied by the AD converter 54 . The signal written into the memory 56 is read out from the memory 56 at a slower speed than the write speed based on a read timing signal supplied from the controller 50 .

The readout speed of a signal from the memory 56 preferably corresponds to such a speed that the horizontal scanning period of a video signal corresponds to de time equal to a time that corresponds to a vertical scanning period of the video signal. Otherwise a different speed can be adapted for reading out. The readout timing from the memory 56 corresponds to the timing of a specific horizontal scan period shown in Fig. 2 (D) during a vertical scan period of a video signal, and the readout of the signal from the memory 56 is every vertical scan period of the Video signal repeated.

Comparable to the memory 28 shown in FIG. 1, the memory 56 can be provided with a plurality of memory sections (memory blocks) for the successive storage of audio signals, which are equal to a time period which corresponds to at least one horizontal sampling period of a video signal, one of which Memory arrangement enables a simple circulation of the successive response of the memory sections for successive writing of the signal and for subsequent reading of the signal with each vertical sampling of the video signal.

The signal read out from the memory 56 is converted in a digital-to-analog conversion circuit 58 into an analog signal, the conversion at the same speed as the readout speed of the signal from the memory 56 and in synchronization with the readout of the signal from the memory 56 is executed based on the timing signal for the conversion output from the controller 50 .

This reduces the frequency of the compressed audio signal in the composite signal shown in FIG. 2 (D) with the ratio that corresponds to the transition from a time corresponding to a horizontal sampling period 1 H of the video signal to a time that corresponds to a vertical sampling period 1 V of the video signal. As a result, the time base of the compressed video signal is increased, whereby the time base of the compressed audio signal is converted into the original time base in real time, ie the time base in real time is restored.

Accordingly, since the compression ratio of the time base of the audio signal in the transmission device 10 is 1 / n, the time base of the audio signal in the receiving device 40 is increased n times, which is why the restored audio frequency in the receiving device is divided by 1 / n.

The output signal of the DA converter 58 is input to a low-pass filter 60 for preventing the passage of a frequency component higher than one of the audio signal, so that only a frequency component of the audio signal is output from the low-pass filter 60 . The output signal of the low-pass filter 60 is amplified by an amplifier 62 , and the amplified signal is output from a terminal 64 to a reproducing device such as a speaker, or it is sent to an audio-video signal recording device such as a VCR for recording a separate audio signal along with the video signal output from a terminal 52 .

In the receiving device 40 , each of the circuits 44 , 48 , 50 , 54 , 56 , 58 and 60 operates as an element of a device for restoring the time base of the compressed audio signal. In addition, the timing controller 50 functions as a control circuit for controlling the circuits 48 , 54 , 56 and 58 in the receiving device 40 together with the synchronization separation circuit 44 .

The timing signals supplied from the timing controller 50 to each of the circuits 48 , 54 , 56 and 58 are related to each other in such a way that they have a predetermined phase relationship with each other and with a video signal. Such a phase relationship can be obtained by generating different timing signals based on the synchronization signals output from the synchronization separation circuit 44 .

As shown in Fig. 4, a transmission device 70 is a composing device for composing a video signal and two analog audio signals for stereo transmission. The transmission device 70 receives the first audio signal via a connection 14 L and the second audio signal via a connection 14 R.

The first analog audio signal, which is input to the terminal 14 L, runs through a volume control 22 L and an amplifier 24 L and is then input to a first analog-to-digital conversion circuit (AD converter) 26 L. The second analog audio signal, which is input to the terminal 14 R, runs through a volume control 22 R and an amplifier 24 R and is then input to a second analog-to-digital conversion circuit (AD converter) 26 R.

The AD converters 26 L and 26 R are activated at a predetermined period based on the timing signals supplied from the controller 20 and convert the analog audio signals into digital signals during the active period.

The output signals of the AD converters 26 L and 26 R are input to a memory 28 . The memory 28 is also input the write timing signal from the controller 20 for controlling the writing speed, and therefore the SpeI writes cher 28 supplied from the AD converters 26 L and 26 R signals, a successively or sequentially. The timing controller 20 also supplies the readout timing signal to the memory so that the signal written in the memory 28 is read out at a speed greater than the write speed.

The readout speed of one of the two signals from the memory 28 preferably corresponds to such a speed that a time corresponding to half the vertical sampling period of the video signal is equal to a time corresponding to half the horizontal sampling period. Otherwise a different speed can be adapted to the readout speed. The readout timing of both signals from memory 28 corresponds to a horizontal scan period of a video signal, preferably within the vertical blanking period, and more preferably a specific horizontal scan line period during the vertical blanking period, each of the two signals occupying half of the specific horizontal scan line period, such as is shown in Fig. 8 (A).

The memory 28 can be provided with a plurality of memory sections (memory blocks) which are provided for the sequential storage of the two audio signals during a time period which corresponds to at least one vertical sampling period of the video signal, so that such a memory arrangement enables a simple circular sequential response of the memory sections successive writing of the signals and for successive reading of the signals with each vertical sampling of the video signal.

The signal read out from the memory 28 is converted into an analog signal in a digital-to-analog conversion circuit (DA converter) 30 . The DA converter 30, a Zeitsteue will also approximate signal input from the timing controller 20 so that the digital-to-analog conversion of the signal that is fed from the memory 28 to be, carried out in synchronization with the readout of the signal from the memory 28th

As shown in Fig. 5, a transmission device 80 is a composing device for composing a video signal and two analog audio signals for stereo transmission. The transmission device 80 receives the first audio signal via a connection 14 L and the second audio signal via a connection 14 R.

The first analog audio signal, which is input to the terminal 14 L, runs through a volume control 22 L and an amplifier 24 L and is then input to a first analog-to-digital conversion circuit (AD converter) 26 L. The second analog audio signal, which is input to the terminal 14 R, runs through a volume control 22 R and an amplifier 24 R and is then input to a second analog-to-digital conversion circuit (AD converter) 26 R.

The AD converters 26 L and 26 R convert the corresponding audio signals with a predetermined period based on timing control signals for conversion to be supplied from the controller 20 into digital signals.

The AD converters 26 L and 26 R convert the audio signals alternately (ie alternately). The AC frequency for conversion is preferably selected so that it is not less than twice the highest frequency of the transmitted audio signals, for example, if the highest frequency of the audio signals is 8 kHz, 16 kHz should be selected as the minimum AC frequency. In addition, it is preferable that the frequency change is synchronized with the horizontal synchronization signal. Therefore, as an alternating frequency, if, for example, the horizontal synchronization frequency of the NTSC system is selected at 15,750 Hz, double or triple the horizontal synchronization frequency such as 31,500 Hz or 47,250 Hz can be selected. The timing signals having such an alternating or clock frequency are output to the AD converters 26 L and 26 R for alternately outputting the converted signals to the signal composing section 72 . The converted signals are supplied from the signal composing section 72 to the memory 28 .

The memory 28 is also supplied with the write timing signal for controlling the write speed by the controller 20 , and therefore the memory 28 sequentially writes the signals provided by the composing section 72 . The timing controller 20 also supplies the read-out timing signal to the memory so that the signal written in the memory 28 is read out at a speed greater than the write speed.

The readout speed of the two composite signals from the memory 28 preferably corresponds to a speed such that a time corresponding to the vertical sampling period of the video signal is equal to a time corresponding to a horizontal sampling period. Otherwise, a different speed can be adapted to the readout speed. The readout timing of the two composite signals from memory 28 corresponds to a horizontal sampling period of a video signal, preferably within the vertical blanking period, and more preferably a specific horizontal scanning line period during the vertical blanking period, each of the two signals with a portion corresponding to the AC frequency during of the specific horizontal scanning line period alternates as shown in Fig. 8 (B).

The memory 28 may be provided with a plurality of memory sections (memory blocks) for successively storing the two audio signals during a period corresponding to at least one vertical sampling period of the video signal, so that such a memory arrangement is a simple, sequential successive response of the memory sections successive writing of the signals and for successive reading of the signals with each vertical sampling of the video signal.

The signal read out from the memory 28 is converted in a digital-to-analog conversion circuit (DA converter) 30 into an analog signal. The DA converter 30 is also a timing control signal supplied from the timing controller 20 so that the digital-to-analog conversion of the signal which is fed from the memory 28 takes place synchronously with the reading of the signal from the memory 28 .

As shown in Fig. 6, a transmission device 90 is a composing device for composing a video signal and two analog audio signals for stereo transmission. The transmission device 90 receives the first audio signal through the connection 14 L and the second audio signal through the connection 14 R.

The first analog audio signal, which is supplied to the connection 14 L, runs through a volume control 22 L and an amplifier 24 L and is then fed to an input of an analog stereo multiplexer circuit 92 . The second analog audio signal, which is input to the terminal 14 R, runs through a volume control 22 R and an amplifier 24 R and is then given to a second input of the analog stereo multiplexer 92 .

The signal output from the analog stereo multiplexer 92 is input to an analog-to-digital conversion circuit (AD converter) 26 . The AD converter 26 is activated with a predetermined period based on the timing signals supplied by the controller 20 and converts the analog multiplexed stereo audio signals into digital signals during the active period.

The output signals of the AD converter 26 are fed to a memory 28 . The memory 28 is also inputted from the controller 20 with the write timing signal for controlling the write speed, whereby the memory 28 sequentially writes the signals supplied from the AD converter 26 . The timing controller 20 also supplies the readout timing signal to the memory 26 , so that the signal written into the memory 28 is read out at a speed greater than the write speed.

The readout speed of the signals from the memory 28 preferably corresponds to such a speed that a time (a period of the original signal) corresponding to the vertical sampling period of the video signal is equal to a time (a period of the readout signal) that is a horizontal one Corresponds to the sampling period. Otherwise, a different speed can be adapted to the readout speed. The readout timing of the signals from the memory 28 corresponds to a horizontal scanning period of the video signal before preferably the vertical blanking period and more preferably a specific horizontal scanning line period during the vertical blanking period, as shown in Fig. 8 (C).

The memory 28 may be provided with a plurality of memory sections (memory blocks) for successively storing the multiplexed audio signals during a time period corresponding to at least one vertical sampling period of the video signal, so that such a memory arrangement provides a simple circular successive response of the memories sections for successive writing of the signal and for successive reading of the signal each time the video signal is sampled vertically.

The signal read out from the memory 28 is converted in a digital-to-analog conversion circuit (DA converter) 30 into an analog signal. The DA converter 30, a Zeitsteue will also approximate signal supplied from the timing controller 20 so that the digital-to-analog conversion of the signal that is supplied from the memory 28 is performed in synchronization with the readout of the signal from the memory 28th

As shown in FIG. 7, a transmission device 100 is an assembly device for assembling a video signal and two analog audio signals for stereo transmission. The transmission device 100 receives the first audio signal via a connection 14 L and the second audio signal via a connection 14 R.

The first analog audio signal, which is input to the terminal 14 L, runs through a volume control 22 L and an amplifier 24 L and is then input to a first input (input) of an electronic switch 102 . The second analog audio signal, which is fed to the terminal 14 R, runs through a volume control 22 R and an amplifier 24 R and is then entered into a second input of the electronic switch 102 .

The electronic switch 102 is gnal by a Zeitsteuerungssi, which is supplied from the timing controller 20, gesteu ert. The output or the output of the electronic switch 102 is connected to an AD converter 26. The AD converter 26 is acti vated at a predetermined period based on the timing signals supplied from the controller 20 and converts the analog audio signals supplied from the electronic switch 102 to digital during the active period Signals around.

The output signals from the AD converter 26 are fed to a memory 28 . The memory 28 is also supplied with write timing signals for controlling the write speed from the controller 20 , whereby the memory 28 sequentially writes the signals supplied from the AD converter 26 . The timing controller 20 also supplies the readout timing signal to the memory so that the signal written into the memory 28 is read out at a faster rate than the write rate.

The readout speed of one of the two signals from the memory 28 preferably corresponds to such a speed that a time corresponding to one half of the vertical sampling period of the video signal is equal to a time corresponding to a horizontal sampling period. Otherwise, a different speed can be adapted to the readout speed. The readout timing of both signals from the memory 28 corresponds to a horizontal scan period of the video signal, preferably within the vertical blanking period, and more preferably during two specific horizontal scan line periods during the vertical blanking period, each of the two signals occupying a specific horizontal blanking line period, as shown in FIG. 8 (D) is shown.

The memory 28 may be provided with a plurality of memory sections (memory blocks) for successively storing the two audio signals during a period corresponding to at least one vertical sampling period of the video signal, so that this memory arrangement enables a simple circular sequential response of the memory sections for successive Allows writing of the signals and subsequent reading of the signals with each vertical scan of the video signal.

The signal read out from the memory 28 is converted in a digital-to-analog conversion circuit (DA converter) 30 into an analog signal. The DA converter 30 is also supplied with a timing signal from the timing controller 20 so that the digital-to-analog conversion of the signal to be supplied from the memory 28 is carried out in synchronization with the reading of the signal from the memory 28 .

In the transmission device 70 shown in FIG. 4, the AD converters 26 L and 26 R each work as one of the elements of a compression device for compressing the time base of a stereo audio signal together with the circuits 18 , 20 , 28 and 30 .

In the transmission device 80 shown in FIG. 5, the AD converters 26 L and 26 R and the signal composition section 72 each work as one of the elements of a compression device for compressing the time base of a stereo audio signal with the circuits 18 , 20 , 28 and 30 together.

In the transmission device 90 shown in FIG. 6, the audio multiplexer 92 and the AD converter 26 each cooperate with the circuits 18 , 20 , 28 and 30 as one of the elements of a compression device for compressing the time base of a stereo audio signal.

In the transmission device 100 shown in FIG. 7, the electronic switch 102 and the AD converter 26 each cooperate with the circuits 18 , 20 , 28 and 30 as one of the elements of a compression device for compressing the time base of a stereo audio signal.

In each of the transmission devices 70 , 80 , 90 and 100 , the synchronization separation circuit 18 is not necessary if the transmission device is connected directly to a video signal generator such as a video camera and synchronization signals are supplied directly from the video signal generator.

In each of the transmission devices 70 , 80 , 90 and 100, the holding or clamping circuits 16 and 32 with the change circuit 34 each work as an element of a composition device for composing the composite audio signal and a video signal comparable to the composition device of the to together in Fig. 1 shown transmission circuit 10.

As a result, the transmitters 70 , 80 , 90 and 100 can transmit two separate audio signals for stereo sound together with an image signal over a common transmission line without exerting any influence on the image signal and without exerting any influence on one another becomes.

As shown in FIG. 9, a receiver 74 receives a composite signal from any of the transmitters 70 , 80 , 90 and 100 shown in FIGS. 4, 5 and 7 via port 42 . The composite signal is input to a synchronization isolation circuit 44 and the clamp circuit 48 .

The synchronization separation circuit 44 separates or extracts the horizontal and vertical synchronization signals from the received composite signal and supplies the separated or extracted synchronization signals to a timing control 50 . The timing controller 50 generates various timing signals based on the synchronization signals supplied from the synchronization isolation circuit 44 . The timing signals generated by controller 50 are applied to latch 48 , AD converter 54 , memory 56, and DA converters 58 L and 58 R.

Based on the timing signals supplied from the controller 50 , the latch circuit 48 holds the composite signal supplied from the terminal 42 at a predetermined voltage level during that shown in Fig. 8 (A) or 8 (B) 1 H period or during the 2 H period from FIG. 8 (D), ie during the period of time of the compressed audio signals played into the video signal. As a result, the audio signal components in the composite video signal are clamped at a predetermined voltage level.

An output signal of the clamp circuit 48 is input to an analog-digital conversion circuit (AD converter) 54 .

The AD converter 54 converts the audio signal output from the hold circuit 48 during the 1 H period shown in FIG. 8 (A) or 8 (B) or during the 2 H period shown in FIG. 8 (D) Converts the timing control signal for conversion supplied by controller 50 to a digital signal.

The signal converted by the AD converter 54 is input to a memory 56 and written into the memory based on the write timing signal supplied from the controller 50 . The memory 56 sequentially writes the signal supplied from the AD converter 54 . The signal written in the memory 56 is read out from the memory 56 at a speed lower than the write speed on the basis of readout timing signals supplied from the controller 50 .

The readout speed of a signal from the memory 56 preferably corresponds to such a speed that a time (duration of the compressed signal) corresponding to one or two horizontal sampling periods of the video signal becomes equal to a time (duration of the decompressed signal) that is vertical Corresponds to the sampling period of the video signal. Otherwise, a different speed can be adapted to the readout speed. The reading of the signal from the memory 56 is repeated each time with the vertical sampling period of the video signal.

Comparable to the memory 28 shown in FIGS. 4, 5 or 7, the memory 56 can be provided with a plurality of memory sections (memory blocks) for successively storing audio signals for a time period which corresponds to at least one horizontal sampling period of the video signal, so that such a memory arrangement allows a simple circular successive addressing of the memory sections for successive writing of the signal and for subsequent reading of the signal with each vertical sampling of the video signal.

A composite signal composed of any of the transmission devices 70 , 80 , 90 and 100 shown in FIGS . 4, 5 and 7 can be separated into a video signal and an audio signal by the receiving device 74 . Therefore, the receiving device 74 has a first and a second DA converter 58 L and 58 R for converting the first and the second audio signals, which are read out from the memory 56 , into corresponding analog signals.

The first and second DA converters 58 L and 58 R accordingly convert the first audio signal and the second audio signal into analog signals at the same speed as the readout speed of the signal from the memory 56 and in synchronization with the readout of the signal from the memory 56 based on conversion timing signals output from the controller 50 to.

The frequency and phase of the timing signal for converting each of the DA converters 58 L and 58 R are preferably equal in frequency and phase to the timing signal for converting the AD converters 26 L and 26 R from any of the transmission devices 70 , 80 and 100 shown in Figs. 4, 5 and 7.

For reading out from the memory 56 and separating the audio signals from the composite signal which has been composed by the transmission device 70 shown in FIG. 4, the timing signals generated by the timing controller 50 of the receiving device 74 are corresponding are, preferably such a speed that a time (duration of the compressed signal), which corresponds to half of the horizontal sampling period, is equal to half of the vertical sampling period of the video signal. Otherwise, a different reading and conversion speed can be adjusted. The readout timing of both the first and the second audio signal from the memory 56 and the conversion time running through both DA converters 58 L and 58 R corresponds to the interpretation sen a specific horizontal scanning period shown in Fig. 8 (A), during a vertical sampling period of a video signal, wherein one of the two audio signals is read and converted during the first half of the vertical sampling period of the video signal and the other audio signal is read out and converted during the second half of the vertical sampling period of the video signal.

For reading out from the memory 56 and separating the audio signals from the composite signal that is composed by the transmission means 80 shown in FIG. 5, the timing signals generated by the timing control 50 of the receiving means 74 correspond to the changing timing of the transmission means 80 , preferably with an alternating alternating frequency which is selected such that it corresponds to not less than twice the highest frequency of the received audio frequency, for example, if the highest frequency of the audio signal is 8 kHz, 16 kHz should be selected as the minimum alternating frequency become. In addition, it is preferable to synchronize the alternating frequency with the horizontal synchronization signal, and therefore the alternating frequency of the horizontal synchronization frequency of the NTSC system, which can be selected, for example, at 15,750 Hz, is preferably twice or three times the horizontal synchronisa frequency of 31,500 Hz or 47,250 Hz selected. Such an alternating or clock frequency is applied to the DA converters 58 L and 58 R for alternately outputting a converted analog audio signal.

The readout speed of the two alternating audio signals composed by the transmission means 80 from the memory 56 preferably corresponds to a speed such that a time corresponding to a horizontal scanning period of the video signal becomes equal to a time corresponding to a vertical scanning period Video signal speaks ent. The readout timing of signals from the memory 56 corresponds to reading out a specific horizontal scanning line period shown in FIG. 8 (B) during a vertical scanning period of a video signal.

For reading out from the memory 56 and separating the audio signals from the composite signal that has been assembled by the transmission device 100 shown in FIG. 7, the timing signals generated by the timing controller 50 of the receiver 74 are generated will preferably correspond to such a speed that a time corresponding to a horizontal scanning period becomes equal to half the vertical scanning period of the video signal. Otherwise, any other speed can be read out and adjusted for conversion. The readout timing of both the first and second audio signals from the memory 56 and the conversion timing through both DA converters 58L and 58R correspond to reading out two specific horizontal scanning periods shown in Fig. 8 (D) during one vertical sampling period of the video signal, wherein one of the audio signals is read out and converted during the first half of the vertical sampling period of a video signal and the other audio signal is read out and converted during the second half of the vertical sampling period of a video signal.

The output signals of the AD converters 58 L and 58 R of the receiver 74 shown in Fig. 9 are corresponding to the amplifiers 62 L and 62 R through low-pass filters 60 L and 60 R to prevent the passage of a frequency component which is higher as such is an audio signal input, whereby the filtered and amplified audio signals from the amplifiers 62 L and 62 R through the terminals 64 L and 64 R to a reproducing device such as a speaker or an audio-video signal recording apparatus such as a video recorder for recording an audio signal separated from the video signal output from the terminal 52 are output.

As shown in FIG. 10, a receiver 84 receives a composite signal from the transmitter 90 shown in FIG. 6 via port 42 . The composite signal is input to a synchronization disconnection circuit 44 and the latch circuit 48 .

The synchronization separation circuit 44 separates the horizontal and vertical synchronization signals from the composite signal or extracts them from the composite signal and supplies the separated synchronization signals to a timing control 50 . The timing controller 50 generates various timing signals based on the synchronization signals supplied from the synchronization disconnection circuit 44 . The timing signals generated by controller 50 are applied to latch 48 , AD converter 54 , memory 56, and DA converter 58 .

On the basis of the power supplied from the controller 50 Zeitsteue approximately signals holds or clamps the holding circuit 48, the composite signal, which is supplied from the terminal 42 on egg nem predetermined voltage level during the 1H period shown in Fig. 8 (C ) is shown fixed, ie during the time in which the compressed audio signals are imported or injected into the video signal. As a result, the audio signal components within the composite video signal are clamped at a predetermined voltage level.

An output signal of the clamp circuit 48 is supplied to an analog-digital conversion circuit 54 .

The AD converter 54 converts the audio signal output from the clamp circuit 48 during the 1 H period shown in FIG. 8 (C) during the 1 H period shown in FIG. 8 (C) the basis of the timing signal for the conversion supplied from the controller 50 to a digital signal.

The signal converted in the AD converter 54 is input to a memory 56 and written into the memory based on the write timing control signal supplied from the controller 50 . The memory 56 successively writes in the signal supplied by the AD converter 54 . The signal written in the memory 56 is read out from the memory 56 at a speed lower than the write speed based on the readout timing signals supplied from the controller 50 .

The readout speed of the signal from the memory 56 preferably corresponds to such a speed that a time corresponding to one or two horizontal scanning periods of a video signal becomes equal to a time corresponding to a vertical sampling period of the video signal. Otherwise, a different speed can be adapted to the readout speed. The reading of the signal from the memory 56 is repeated every vertical sampling period of the video signal.

Comparable to the memory 28 shown in Fig. 6, the memory 56 may be provided with a plurality of memory sections (memory blocks) for sequentially storing audio signals corresponding to a period corresponding to at least one horizontal scanning period of a video signal, so that this memory arrangement is simple encircling (ie using the memory sections one after the other) successive addressing or use of the memory sections for successive writing of the signal and for subsequent reading of the signal with each vertical sampling of the video signal he permits.

To read from the memory 56 and to separate the audio signals from the composite signal which has been assembled by the transmission device 90 shown in FIG. 6, the timing signals corresponding to the timing control 50 of the reception device 84 shown in FIG. 10 are accordingly it is generated, preferably such a speed that a time corresponding to a horizontal scanning period becomes equal to a time corresponding to a vertical scanning period of the video signal. Otherwise, another speed can be adjusted for reading and conversion. The readout timing of the multiplexed first and second audio signals from the memory circuit 56 and the conversion timing by the DA converter 58 corresponds to reading out a specific horizontal scanning period shown in Fig. 8 (C) during a vertical scanning period of a video signal.

The multiplexed stereo signals output from the DA converter 58 are input to a demultiplexer circuit 61 via a low-pass filter 60 . The low-pass filter 60 prevents the passage of frequency components which are higher than those of an audio signal, as a result of which filtered multiplexed stereo audio signals are supplied to the demultiplexer circuit 61 . The de multiplexer circuit separates the first and second audio signals and feeds these two audio amplifiers 62 L and 62 R to output two separate audio signals via the connections 64 L and 64 R.

In the receiving devices 74 and 84 , the circuits 44 , 48 , 50 , 54 and 56 each operate as an element of a device for extracting the compressed audio signal from a composite video signal. In addition, the timing controller 50 functions as a control circuit for controlling the circuits 48 , 54 and 56 in the receivers 74 and 84 together with the synchronization separation circuit 44 .

In the receiving device 74 , the DA converters 58 L, 58 R and the low-pass filters 60 L, 60 R each work as one of the elements of a device for restoring the time base of the compressed audio signal with other circuits 44 , 48 , 50 , 54 and 56 .

In the receiving device 84 , the DA converter 58 , the demultiplexer circuit 61 and the low-pass filter 60 L and 60 R each work as one of the elements of a means for restoring the time base of the compressed audio signal with other circuits 44 , 48 , 50 , 54 and 56 together.

The timing signals supplied from the timing controller 50 to each of the circuits 48 , 54 , 56 and 58 or 58 L and 58 R have such a relationship that they have a predetermined phase relationship with each other and with a video signal. Such a phase relationship can be obtained by generating various timing signals based on the synchronization signals output from the synchronization separation circuit 44 .

In order to receive the composite signals that have been assembled by one of the transmission devices 70 , 80 and 100 , the memory circuit 56 of the reception device 74 can further comprise two readout circuits, each of which outputs separately to the two DA converters 58 L and 58 R, and each Ausleseaus reproducing or each read-out output may have a delay circuit which is controlled by the timing controller 50 so that the timing of the first and the second audio signal per fect coincide with each other, alternatively, an additional delay circuit which is controlled by the timing controller 50 ge, 58 L and 58 R can be added to each of the DA converters.

Because the degree of compression of the audio signals is equal to the ratio the vertical scan period and the horizontal scan period is, for example, in the case of the NTSC system in which the ver tical sampling period 16.666 ms and the horizontal sampling period 53 µs  the compression ratio is 16.666 ms / 53 µs ≈ 314.

Accordingly, it is by using a compression method ratio of 314 possible, for example an audio signal with 14 kHz and compress it into an NTSC video signal with a Use bandwidth of 4.5 MHz or combine with it (314 x 14 kHz = 4.396 MHz).

Depending on the audio frequencies that are used and the Video signal bandwidth, it is possible to have more than two audio signals to compress and on the transmission side into a video signal insert or combine with this and using a common transmission line these two audio signals to extract and restore on the receiving side.

It is also possible, for example, to take such audio signals during every other vertical sampling period and that Audio signal used in different horizontal sampling periods zen, or it into a section of a single one or more horizontal scanning periods. Are accordingly unlimited combinations of audio signal compression levels, Audio signal compression durations and audio signal composition timings are possible, and limitless combinations are similar of recovery and extraction facilities for one single or for several audio signals according to the compression ratio, the compression duration or the compression time lapse that for the composition of the audio signals and a Video signal have been used, possible.

Claims (26)

1. A device for transmitting television signals with a video signal and an audio signal, which comprises:
a compression device ( 18 , 20 , 26 , 28 , 30 , 26 L, 26 R, 92 , 102 ) for compressing a time base of an audio signal to be transmitted and
composing means ( 16 , 32 , 34 ) for inserting the compressed video signal into a video signal and for transmitting the composite signal over a common transmission line. 2. Device according to claim 1, characterized in that the composition means comprises:
an analog-digital conversion circuit ( 26 , 26 L, 26 R) for converting the audio signal into a digital signal,
a memory ( 28 ) for storing output signals of the analog-digital conversion circuit,
a control circuit ( 20 ) for controlling the writing of the signal into the memory and the reading out of the signal from the memory and for outputting the signal stored in the memory at a speed which is greater than the writing speed, and
a digital-to-analog conversion circuit ( 30 ) for converting the signal read from the memory into an analog signal. 3. Device according to claim 2, characterized in that the composition means comprises:
an output signal switching circuit ( 34 ) controlled by the control circuit ( 20 ) for inserting an output signal of the digital-to-analog conversion circuit ( 30 ) into the video signal during a switching period according to a timing controlled by the control circuit ( 20 ). 4. Device according to claim 2 or 3, characterized in
that the audio signal has a first and a second audio signal for stereo sound, and
that the analog-to-digital conversion circuit has:
a first AD converter ( 26 L) for converting the first audio signal into a digital signal,
a second AD converter ( 26 R) for converting the second audio signal into a digital signal and
a feeder for independently feeding the converted digital signals of the first audio signal and the second audio signal to the memory ( 28 ). 5. Device according to one of claims 2 to 4, characterized in
that the audio signal has a first and a second audio signal for stereo sound, and
that the analog-to-digital conversion circuit has:
a first AD converter ( 26 L) for converting the first audio signal into a digital signal,
a second AD converter ( 26 R) for converting the second audio signal into a digital signal and
a signal composing section ( 72 ) for composing the output signals from both AD converters ( 26 L, 26 R) and supplying them to the memory ( 28 ). 6. Device according to one of claims 2 to 5, characterized in
that the audio signal has a first and a second audio signal, and
that the compression means further comprises a stereo audio signal multiplexer circuit ( 92 ) for multiplexing the first and second audio signals and outputting them to the analog-digital conversion circuit ( 26 ). 7. Device according to one of claims 2 to 6, characterized in
that the audio signal has a first and a second audio signal, and
that the compression means further comprises an audio signal changing circuit ( 102 ) for alternating switching of the first and second audio signals and outputting them to the analog-digital conversion circuit ( 26 ). 8. Device according to one of claims 3 to 7, characterized in
that the assembly device further comprises:
a first clamping circuit ( 16 ) for clamping the video signal to be supplied to the output signal switching circuit ( 34 ) to a predetermined voltage level and
a second clamping circuit ( 32 ) for clamping the compressed audio signals to be output from the digital-to-analog conversion circuit ( 30 ) and to be fed to the output signal switching circuit ( 34 ) to the predetermined voltage level. 9. Device according to one of claims 1 to 8, characterized ge features that the compression means the time base of the audio signal compressed in a degree that is a time that of a vertical Sampling period of the video signal corresponds to one time which corresponds to a horizontal scanning period of the video signal speaks. 10. Device according to one of claims 4 to 9, characterized ge features that the compression means the time base of the first audio signals and the second audio signal compressed to one degree, that is a time corresponding to a vertical scan period of the video i gnals corresponds to a time equal to a horizontal Corresponds to the sampling period of the video signal. 11. Device according to one of claims 4 to 9, characterized ge features that the compression means the time base of the first audio signals and the second audio signal compressed to one degree, that is a time corresponding to a vertical scan period of the video i gnals corresponds to a time equal to the two horizontal Sampling periods of the video signal corresponds. 12. Device according to one of claims 1 to 11, characterized ge features that the composition means the compressed audio signal during the vertical blanking period of the video signal.   13. Device according to one of claims 1 to 12, characterized in
that the compression device has:
an analog-digital conversion circuit ( 26 , 26 L, 26 R) for converting the audio signal into a digital signal, a memory ( 28 ) for storing output signals of the analog-digital conversion circuit,
a control circuit ( 20 ) for controlling the writing of the signals into the memory and the reading out of the signals from the memory, the control circuit ( 20 ) writing the audio signal into the memory ( 28 ) and the written signal from the memory ( 28 ) each vertical Outputs a sampling period at a rate that a time corresponding to a vertical sampling period of the video signal is equal to a time corresponding to a horizontal sampling period of the video signal, and
a digital-to-analog conversion circuit ( 30 ) for converting the signal read from the memory ( 28 ) into an analog signal, and
that the composing means sets an output signal of the digital tal-to-analog converting circuit ( 30 ) during a horizontal scanning period of the vertical blanking period of the video signal. 14. Device according to one of claims 4 to 13, characterized in
that the compression device has:
a memory ( 28 ) for storing the output signals of the first AD converter ( 26 L) and the second AD converter ( 26 R),
a control circuit ( 20 ) for controlling the writing of the signals into the memory and the reading out of the signals from the memory, the control circuit ( 20 ) writing the converted digital signals of the first audio signal and the second audio signal into the memory ( 28 ) and that outputs the written signal from the memory every one vertical sampling period at a rate that a time corresponding to one vertical sampling period of the video signal becomes equal to a time corresponding to two horizontal sampling periods of the video signal, and
a digital-to-analog conversion circuit ( 30 ) for converting the signal read from the memory ( 28 ) into an analog signal, and
that the composing means uses an output signal of the digital tal-to-analog conversion circuit ( 30 ) during two horizontal scanning periods of the vertical blanking period of the video signal. 15. Device according to one of claims 2 to 14, characterized in that the composing means uses an output signal of the digital-ana log conversion circuit ( 30 ) during a specific horizontal sampling period in the vertical blanking period of the video signal. 16. Device according to one of claims 2 to 14, characterized in that the composition means uses an output signal from the digital-to-analog conversion circuit ( 30 ) during two specific ho rizontaler sampling periods in the vertical blanking period of the video signal. 17. Device for receiving television signals that come together set signals with an inserted audio signal, its time base is compressed, contained and over a common over transmission line are transmitted with an extraction and restoration facility for extra hieren the compressed audio signal from the composite Signal and to restore the time base of the extracted Audio signal. 18. Device according to claim 17, characterized in that the extraction and restoration device comprises:
an analog-to-digital conversion circuit ( 54 ) for extracting the audio signal from the composite signal and for converting the audio signal into a digital signal,
a memory ( 56 ) for storing an output signal from the analog-to-digital conversion circuit ( 54 ),
a control circuit (50) for controlling writing of the signal into the memory (56) and the reading of the signal from the SpeI cher (56) and for outputting the data stored in the memory (56) signals with a speed which is slower than the write speed of the signal in the memory ( 56 ), and a digital-to-analog conversion circuit ( 58 , 58 L, 58 R) for converting the signal read from the memory ( 56 ) into an analog signal. 19. Device according to claim 18, characterized in
that the audio signal is an alternating signal from the first and
the second audio signal for stereo sound, and
that the digital-to-analog conversion circuit has:
a first DA converter ( 58 L) for converting the first audio signal into an analog signal and
a second DA converter ( 58 R) for converting the second audio signal into an analog signal. 20. Device according to claim 18 or 19, characterized in that
that the audio signal is an alternating combined signal of the first and the second audio signal for stereo sound, and
that the digital-to-analog conversion circuit has:
a first DA converter ( 58 L) for converting the first audio signal into an analog signal and
a second DA converter ( 58 R) for converting the second audio signal into an analog signal. 21. Device according to one of claims 18 to 20, characterized in
that the audio signal is a multiplex signal of the first and the two th audio signal for stereo sound multiplex, and
that the extracting and restoring means further comprises a demultiplexer circuit ( 61 ) for decoding the multiplex signals output from the digital-to-analog conversion circuit ( 58 ) and for separately outputting the first audio signal and the second audio signal. 22. Device according to one of claims 18 to 21, characterized in that the extracting and restoring device further comprises a clamping circuit ( 48 ) for clamping a composite signal which is to be fed to the analog-digital conversion circuit ( 54 ) has a predetermined voltage level. 23. Device according to one of claims 18 to 22, characterized in that the extraction and restoration device further comprises a low-pass filter ( 60 , 60 L, 60 R) for removing a signal component with a frequency higher than that of the digital Analog conversion circuit ( 58 , 58 L, 58 R) is output audio signal frequency. 24. Device according to one of claims 17 to 23, characterized in
that the time base of the audio signal is compressed to a degree that a time corresponding to a vertical sampling period of the video signal becomes equal to a time corresponding to a horizontal sampling period of the video signal, and
that the extracting and restoring means restores the time base of the extracted audio signal to a degree that a time corresponding to a horizontal sampling period of the video signal becomes equal to a time corresponding to a vertical sampling period of the video signal. 25. Device according to one of claims 17 to 23, characterized in
that the time base of the audio signal in the composite signal is compressed to a degree that a time corresponding to a vertical sampling period of the video signal becomes equal to a time corresponding to two horizontal sampling periods of the video signal, and
that the extracting and restoring means restores the time base of the extracted audio signal to a degree that a time corresponding to two horizontal sampling periods of the video signal becomes equal to a time corresponding to a vertical sampling period of the video signal. 26. Device according to one of claims 17 to 25, characterized ge features that the audio signal into the composite signal during the vertical sampling period of the video signal is inserted, and that the extraction and restoration facility the Audio signal from the composite signal by separating the Sync signal from the video signal and by applying of the separated synchronization signal to a control circuit to output a precise time control to control the extra period of the audio signal.