JPH05110995A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide a device which reduces sag by accurately separating synchronizing signals of a reproduced video signal and normally performing the clamping operation. CONSTITUTION:When PCM audio signals are multiplexed in time division during the blanking period of a recorded video signal and are recorded and reproduced, the signal obtained by delaying the reproduced signal by a certain time and the reproduced signal are switched by a switch circuit 31 to perform FM demodulation at the time of reproducing. The signal obtained by delaying the reproduced signal by a prescribed horizontal scanning period and the reproduced signal are switched by the switch circuit 31 to perform FM demodulation. Such FM signal is generated by an FM signal generator that it has a certain frequency after FM demodulation, and the signal in the PCM audio signal area of the reproduced video signal after FM demodulation is switched to this signal having the certain frequency. Delay elements 30 are provided which delay the reproduced signals of heads 12a, 12b in the preceding stage of a head switching circuit 17, and reproduced signals of heads 12a, 12b are switched in the PCM audio signal area to perform FM demodulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is constructed so that a video signal is FM-modulated and a digital audio signal (hereinafter referred to as a PCM audio signal) is time-division multiplexed and recorded / reproduced during a blanking period of the FM video signal. The present invention relates to a video signal recording / reproducing device that has been recorded.

[0002]

2. Description of the Related Art FIG. 17 is a magnetic recording / reproducing apparatus which is an example of a conventional video signal recording / reproducing apparatus for time-divisionally multiplexing and recording / reproducing a PCM audio signal in a part of a vertical blanking period of an FM-modulated video signal. Device (hereinafter referred to as VTR)
It is a block diagram showing. In the figure, 1 is an A / D that converts an input video signal from an analog signal to a digital signal.
A converter 2 is a first sync separation circuit for performing sync separation from an input video signal, and a reference numeral 3 is a recording signal processing circuit, which uses the sync signal output from the first sync separation circuit 2 as a reference. Recording signal processing such as inserting blanking data is performed. Further, in the recording signal processing circuit 3, the FM
It also generates and outputs a timing pulse for inserting a PCM audio signal into the video signal. Reference numeral 4 is a D / A converter for converting a digital signal into an analog signal, 5 is a pre-emphasis circuit for emphasizing high frequency components of the video signal, 6 is an FM modulator for FM-modulating the video signal, and 7 is a PCM encoder. After the shuffling process and the addition of an error correction code are performed on the input audio signal, the digital audio signal of one field period is output from the FM modulator 6 based on the timing pulse output from the recording signal processing circuit 3. Time-axis compression processing is performed for insertion in the vertical blanking period of the output FM video signal, and digitally modulated and output.
Reference numerals 8 and 9 are switches, 10 is an adder for adding the outputs of the switches 8 and 9, 11 is a recording amplifier, 12a and 12b are rotary heads, and 13 is a magnetic tape.

Reference numerals 16a and 16b denote the rotary heads 12a.
And a head amplifier for amplifying the reproduction signal from 12b,
Reference numeral 17 denotes a head switching circuit for switching the outputs from the head amplifiers 16a and 16b based on a head switching signal,
Reference numeral 18 is a reproduction equalizer for compensating the frequency characteristic of the reproduction FM video signal, 19 is a limiter for removing the amplitude fluctuation component of the reproduction FM video signal output from the reproduction equalizer 18, and 20.
Is an FM demodulator, 21 is a de-emphasis circuit having the inverse characteristic of the pre-emphasis circuit 1, 22 is a clamp circuit, 23 is an A / D converter for converting a reproduced video signal from an analog signal to a digital signal, 24 Is a second sync separation circuit that separates the sync signal from the reproduced video signal, and 25 is a reproduction such as time-axis correction and dropout compensation of the reproduced video signal based on the sync separation signal output from the second sync separation circuit 24. A reproduction signal processing circuit for performing signal processing, 26 is D
An A / A converter 27 is a PCM decoder, which detects the PCM audio signal of the one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling process, error correction process, etc. The audio signal is restored and output.

FIG. 18 is a top view of a rotary head used in a VTR, and 14 is a rotary head 12a, 12a.
a rotating drum with b mounted at 180 ° intervals,
Reference numerals 15a and 15b are guide pins for winding the magnetic tape 13 on the rotary drum 14.

Next, the operation will be described. In the block diagram of FIG. 17, the input video signal is A / D converted by the A / D converter 1, and then, in the recording signal processing circuit 3, based on the sync separation output from the first sync separation circuit 2. Recording signal processing such as inserting blanking data is performed. The recording signal processing circuit 3 also generates and outputs a timing pulse for inserting the PCM audio signal into the FM video signal. The output of the recording signal processing circuit 3 is converted from a digital signal to an analog signal by the D / A converter 4 and input to the pre-emphasis circuit 5. The pre-emphasis circuit 5 emphasizes the high frequency component of the video signal and outputs it to the FM modulator 6, and the FM modulator 6 FM-modulates the video signal. On the other hand, the audio signal is input to the PCM encoder 7, subjected to shuffling processing, addition of error correction code, etc., and then the digital audio signal of one field period is converted into the digital audio signal based on the timing pulse output from the recording signal processing circuit 3. The FM output from the FM modulator 6
It is subjected to time-axis compression processing for insertion in the vertical blanking period of the video signal, digitally modulated and output.

Thereafter, the PCM audio signal output from the PCM encoder 7 in the one field period is FM.
The signal is inserted into the vertical blanking period of the modulated video signal (FM video signal) at the timing shown in FIG. 19, for example, and is output to the recording amplifier 11. A timing pulse output from the recording signal processing circuit 3 is sent to the switches 8 and 9, and an FM video signal and a PCM audio signal are switched and added by an adder 10 to create a recording signal. Then, the recording amplifier 11 outputs the above-mentioned recording signal FM.
The rotary head 12 that amplifies the video signal and the PCM audio signal
Data is recorded on the magnetic tape 13 with a and 12b.

At this time, the magnetic tape 13 is the rotating drum 14
On the other hand, as shown in FIG. 18, it is strongly wound by 180 °, and even when the recording current is constantly flowing through the rotary heads 12a and 12b, the data is recorded on the magnetic tape 13 when the rotary head is in contact with the magnetic tape 13. It is only for the period of time. Therefore, the recording pattern on the magnetic tape 13 is divided into two areas a and b as shown in FIG. 20, and the recording signal of one field is recorded on one track. In addition,
In the figure, a indicates a track recorded by the rotary head 12a, and b indicates a track recorded by the rotary head 12b. Further, since the PCM audio signal is time-division multiplexed and recorded during the vertical blanking period of the FM video signal,
The portion where the PCM audio signal is recorded is the shaded portion.

Next, the operation during reproduction will be described. The reproduced FM video signal reproduced by the rotary heads 12a and 12b and the PCM audio signal mixed at the time of recording are amplified by the head amplifiers 16a and 16b, respectively. Then, the reproduction signal output from each of the head amplifiers 16a and 16b is selected by the head switching circuit 17 from the reproduction signal from the rotary head in contact with the magnetic tape 13 as shown in FIG. 21, based on the head switching signal. Then, the reproduction signal is switched to one reproduction signal (FIG. 21 (c)). Then, the reproduction signal from the head switching circuit 17 is sent to the reproduction equalizer 18 and the PCM decoder 27. In the PCM decoder 27, the P of the one field period inserted in the vertical blanking period of the reproduced signal is used.
While detecting the CM voice signal, error correction, deshuffling processing, error correction processing, etc. are performed to restore the original voice signal and output it.

Generally, when an FM signal is recorded and reproduced by an electromagnetic conversion system using a tape and a head, the lower sideband is emphasized and the upper sideband is suppressed so that the modulation index changes and at the same time the sideband unbalance occurs. Therefore, the reproduced FM signal corresponding to the rising portion (FIG. 22A) of the video signal in which the high frequency component is emphasized by the pre-emphasis circuit 5 is
As shown in FIG. 22 (b), it is greatly squeezed. Therefore, the reproduction equalizer 18 compensates the frequency characteristic of the reproduced FM video signal by suppressing the lower sideband and emphasizing the upper sideband with the frequency characteristic as shown in FIG. The output of is reduced in the manner of constriction as shown in FIG. Then, the output of the reproduction equalizer 18 is sent to the limiter 19 to remove the amplitude fluctuation component of the reproduction FM video signal, and its output is as shown in FIG. 22 (d).

Next, the reproduction signal output from the limiter 19 is input to the FM demodulator 20 and FM demodulated. The de-emphasis circuit 21 attenuates the high frequency component emphasized at the time of recording to obtain a reproduced video signal in which high frequency noise is reduced. This reproduced video signal is then input to the clamp circuit 22 and is clamped so that the input voltage level of the A / D converter 23 is reached. The clamp circuit 22 separates the sync signal of the reproduced video signal to generate a clamp pulse, and clamps the sync signal tip of the reproduced video signal to a predetermined DC voltage level. The reproduced video signal clamped by the clamp circuit 22 is converted from an analog signal to a digital signal by the A / D converter 23 and sent to the reproduced signal processing circuit 25. The second sync separation circuit 24 separates the sync signal from the reproduced video signal. The reproduction signal processing circuit 25 performs reproduction signal processing such as time axis correction and dropout compensation on the reproduction video signal on the basis of the sync separation output from the second sync separation circuit 24, and the D / A converter 26. The digital reproduction video signal is D / A converted and output.

[0011]

In the conventional video signal recording / reproducing apparatus as described above, at the time of recording, the PCM audio signal is time-division multiplexed and recorded in the vertical blanking period of the FM-modulated video signal, During reproduction, the reproduced FM video signal and the mixed PCM audio signal are FM-demodulated as they are.
On the other hand, since the PCM audio signal has a pulse waveform and thus has a wide-band signal component, the PCM audio signal band overlaps with the video signal band as shown in FIG.
As described above, the reproduced FM video signal and the PCM audio signal are FM.
When demodulated, the output waveform of the FM demodulator 20 becomes a noise-like signal waveform in the PCM audio signal area, as shown in FIG.

Further, the reproduction signal shown in FIG.
Before demodulation, as shown in FIG. 26B, when the FM video signal and the PCM audio signal in the reproduction signal are separated and the reproduction signal processing such as the FM demodulation is performed thereafter, the reproduction FM video signal (see FIG. 26) is also generated. In the PCM audio signal region period in (b)), there is no signal portion, and when the reproduced FM video signal in which this signalless portion exists is FM demodulated, FIG.
As shown in FIG. 6 (c), the FM demodulated waveform in the PCM audio signal region, which is a non-signal portion, becomes a signal waveform like noise.

On the other hand, when the clamp circuit 22 in the preceding stage of the A / D converter 23 is configured to separate the sync signal of the reproduced video signal to generate a clamp pulse and clamp the leading end of the sync signal, the reproduced video signal If there is noise as shown in FIGS. 25 and 26 (c) in the middle PCM audio signal area, normal synchronization separation cannot be performed, and the clamp operation is performed at the lower end of the noise portion in the PCM audio signal area.
There is a problem that the signal level of the input reproduction video signal of the A / D converter 23 is not clamped to a normal value and the reproduction video signal is broken.

Further, in the PCM audio signal region of the reproduced video signal, it is not known what kind of waveform the output waveform of the FM demodulator 20 will be demodulated, and noise above the white level or below the sync signal tip as shown in FIG. If it is output or has a DC component, it causes sag, and there is a problem that a good reproduced video signal cannot be obtained because the hue changes in part of the reproduced video signal. .

The present invention has been made to solve the above-mentioned problems, and it is possible to accurately perform synchronous separation of reproduced video signals, to normally operate the clamp circuit, and to reduce sag. It is an object of the present invention to obtain a video signal recording / reproducing device capable of producing a good reproduction video signal.

[0016]

A video signal recording / reproducing apparatus according to the present invention includes a PCM area signal generator for generating a control signal indicating a PCM audio signal area in a reproduction signal at the time of reproduction, and a reproduction signal for a predetermined period τ. And a switch circuit for switching between the reproduction signal and the output of the delay element according to the PCM area signal output from the PCM area signal generator, and the output of the switch circuit is FM demodulated. It was done.

Further, the video signal recording / reproducing apparatus according to the present invention delays the reproduction signal by a PCM area signal generator for generating a control signal indicating the PCM audio signal area in the reproduction signal during reproduction. A delay element is provided, and a switch circuit for switching between the reproduction signal and the output of the delay element is provided in accordance with the PCM area signal output from the PCM area signal generator so that the switch circuit output is FM demodulated. It was done.

Further, the video signal recording / reproducing apparatus according to the present invention includes a PCM area signal generator for generating a control signal indicating a PCM audio signal area in the reproduction signal at the time of reproduction, and an FM signal obtained by FM-modulating a signal of a constant frequency. And an FM signal generator for generating a reproduction signal and the FM signal according to the PCM area signal output from the PCM area signal generator.
By providing a switch circuit that switches the output of the signal generator,
The output of the switch circuit is FM demodulated.

Further, the video signal recording / reproducing apparatus according to the present invention includes a PCM area signal generator for generating a control signal indicating a PCM audio signal area in the reproduction signal during reproduction, and respective reproduction signals reproduced from respective heads. And a switch circuit for switching the reproduction signal from each head and the output of each of the delay elements according to the PCM area signal which is the output of the PCM area signal generator. A head switching circuit for selecting and switching the output of each switch circuit is provided, and the output of the head switching circuit is FM demodulated.

[0020]

The video signal recording / reproducing apparatus of the present invention is a PC
A switch circuit for switching between a reproduction signal and a signal obtained by delaying the reproduction signal by a predetermined period τ based on the PCM area signal indicating the M audio signal area is provided, and the output of the switch circuit is FM demodulated. The signal in the audio signal area is replaced with the playback video signal in the previous field, the playback video signal is accurately separated in synchronization, the clamp circuit can operate normally, and the playback video signal does not break down, resulting in a good playback image. Can be obtained. Further, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

Further, the video signal recording / reproducing apparatus according to the present invention is provided with a switch circuit for switching the reproduction signal and a signal obtained by delaying the reproduction signal by a predetermined horizontal scanning period based on the PCM area signal indicating the PCM audio signal area. Since the output of the switch circuit is FM-demodulated, the signal of the PCM audio signal area in the reproduced video signal is replaced with the repeated video signal of the data of the last line of the previous field to accurately perform synchronous separation of the reproduced video signal and clamp it. The circuit can operate normally, the playback video signal does not break down,
A good reproduced image can be obtained. Further, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

Further, in the video signal recording / reproducing apparatus of the present invention, in the switch circuit capable of switching based on the PCM area signal indicating the PCM audio signal area, the reproduced signal and the FM signal obtained by FM-modulating the signal of the constant frequency are switched. , Since the signal in the PCM audio signal area in the reproduced video signal after FM demodulating the output of the switch circuit is a signal of a constant frequency, the reproduced video signal is accurately separated and the clamp circuit operates normally. Therefore, the reproduced video signal does not break down, and a good reproduced image can be obtained. Moreover, since the signal switched in the PCM audio signal area is not the signal of only the DC level, the sag can be reduced.

Further, the video signal recording / reproducing apparatus according to the present invention, based on the PCM area signal indicating the PCM audio signal area, each reproduction signal reproduced from each head and each reproduction signal delayed by a certain period τ. Are switched by the switch circuit, and the outputs of the respective switch circuits are selected by the head switching circuit and switched to form one reproduced signal, and the output of the head switching circuit is FM demodulated. Therefore, in the PCM audio signal area in the reproduced video signal. Since the signal is replaced with the reproduced video signal of the previous field, the reproduced video signal can be accurately synchronized and separated, and the operation of the clamp circuit can be performed normally, the reproduced video signal does not break down and a good reproduced image can be obtained. .. Further, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

[0024]

EXAMPLES Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a VTR according to the first embodiment. In FIG. 1, recording systems 1 to 13
Since the reproducing systems 16 to 26 are exactly the same as the above-mentioned conventional apparatus, detailed description thereof will be omitted.

Reference numeral 28 denotes a PCM decoder which detects the PCM audio signal of one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling processing, error correction processing and the like to recover the original audio signal. Restore and output. Reference numeral 29 is a PCM area signal generator for generating a PCM area signal indicating the PCM audio signal area of the reproduction signal in the PCM decoder 28, and 30 is a delay period τ.
The delay element 31 is a switch circuit which can be switched by the PCM area signal output from the PCM area signal generator 29.

Next, the operation will be described. During recording, the input video signal is A / D converted by the A / D converter 1, and then, in the recording signal processing circuit 3, blanking data is generated based on the sync separation output from the first sync separation circuit 2. Recording signal processing such as insertion is performed. The recording signal processing circuit 3 also generates and outputs a timing pulse for inserting the PCM audio signal into the FM video signal. The output of the recording signal processing circuit 3 is converted from a digital signal to an analog signal by the D / A converter 4 and sent to the pre-emphasis circuit 5. The pre-emphasis circuit 5 emphasizes the high frequency component of the video signal and outputs it to the FM modulator 6, and the FM modulator 6 FM-modulates the video signal.
On the other hand, the audio signal is input to the PCM encoder 7, subjected to shuffling processing, addition of error correction code, etc., and then the digital audio signal of one field period is converted into the digital audio signal based on the timing pulse output from the recording signal processing circuit 3. F
A time-axis compression process is performed to insert the signal into the vertical blanking period of the FM video signal output from the M modulator 6, and the signal is digitally modulated and output.

After that, the PCM audio signal output from the PCM encoder 7 in the one field period is FM.
The recording amplifier 1 is inserted in the vertical blanking period of the modulated video signal at a timing as shown in FIG.
It is output to 1. A timing pulse output from the recording signal processing circuit 3 is sent to the switches 8 and 9, and an FM video signal and a PCM audio signal are switched by the adder 10 to generate a recording signal. Then, in the recording amplifier 11, the FM video signal and the PCM which are the above recording signals.
The audio signal is amplified and recorded on the magnetic tape 13 by the rotary heads 12a and 12b. At this time, the magnetic tape 13 is tightly wound around the rotary drum 14 by 180 ° as shown in FIG. Only during the period when the rotary head is in contact with the magnetic tape 13. Therefore, the recording pattern on the magnetic tape 13 is divided into two areas a and b as shown in FIG. 20, and the recording signal of one field is recorded on one track. In the figure, a indicates a track recorded by the rotary head 12a, and b indicates a track recorded by the rotary head 12b. Also, the PCM audio signal is F
Since the signals are time-division multiplexed and recorded during the vertical blanking period of the M video signal, the portion where the PCM audio signal is recorded is the shaded portion. The recording operation up to this point is the same as in the conventional example.

Next, the operation during reproduction will be described. The reproduced FM video signal reproduced from the rotary heads 12a and 12b and the PCM audio signal mixed at the time of recording are the head amplifier 1
It is amplified by 6a and 16b. Then, the reproduction signals output from the head amplifiers 16a and 16b are
In the head switching circuit 17, the reproduction signal from the rotary head that is in contact with the magnetic tape 13 is selected and switched based on the head switching signal as shown in FIG.
One reproduction signal (FIG. 21 (c)) is obtained. The reproduction signal from the head switching circuit 17 is supplied to the reproduction equalizer 1
8 and also to the PCM decoder 28.
The PCM decoder 28 detects the PCM voice signal of one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling process, error correction process, etc. to restore the original voice signal and output it. . On the other hand, the reproduction equalizer 18 compensates the frequency characteristic of the reproduction FM video signal of the input reproduction signal and sends it to the limiter 19, which removes the amplitude fluctuation component of the reproduction FM video signal.

By the way, when the FM demodulator 20 directly demodulates the reproduced FM video signal and the PCM audio signal multiplexed in the vertical blanking period as in the conventional example,
The reproduced video signal waveform in the PCM audio signal area is shown in FIG.
As shown in (a), a signal waveform like noise is output.

Therefore, the reproduced signal output from the limiter 19 is sent to the switch circuit 31 and the delay element 30,
As shown in FIG. 2B, the signal in the PCM audio signal area is switched to the reproduced FM video signal in the previous field. Here, the PCM area signal generated by the PCM area signal generator 29 in the PCM decoder 28 is sent to the switch circuit 31. The PCM area signal generator 29 is
In the CM decoder 28, the end timing of the PCM audio signal area of the reproduction signal is detected, and the start time of the next PCM audio signal area is predicted from the above detection result to generate the PCM area signal indicating the PCM audio signal area. is doing.

In the PCM domain signal generator 29, the PC
A pulse indicating the M audio signal area and the video signal area is generated and sent to the switch circuit 31. In the switch circuit 31,
In the video signal area, the reproduced signal output from the limiter 19 shown in FIG. 3A is selected, while in the PCM audio signal area, the output of the delay element 30 having a delay time τ as shown in FIG. 3B is selected. Switch to do so. From the delay element 30, P
Since the reproduced FM signal obtained by delaying the signal in the previous field of the CM audio signal area by τ is output, the signal in the PCM audio signal area is the reproduced FM signal for the τ period of the previous field as shown in FIG. 3C. Becomes

Therefore, the reproduced FM signal output from the switch circuit 31 to be input to the FM demodulator 20 has the PCM audio signal inserted in the PCM audio signal area as shown in FIG. 3C. Since the reproduced FM signal for the τ period of the field before the vertical blanking period is inserted, the output of the switch circuit 31 is FM demodulated by the FM demodulator 20 and the pre-emphasis in the recording circuit is performed by the de-emphasis circuit 21. When the high frequency component emphasized by the circuit 5 is attenuated, a reproduced video signal in which high frequency noise is reduced as shown in FIG. 2B is obtained. Then, since the signal in the PCM audio signal area is replaced with the reproduced video signal for the τ period of the previous field, synchronous separation of the reproduced video signal can be accurately performed and the operation of the clamp circuit 22 is normally performed. Become. Further, since the synchronization signal is added to the signal in the PCM audio signal area, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

The reproduced video signal output from the de-emphasis circuit 21 is clamped at the tip of the sync signal to a predetermined DC voltage level in the clamp circuit 22, and is converted from an analog signal to a digital signal in the A / D converter 23. It is A / D converted and sent to the reproduction signal processing circuit 25. The second sync separation circuit 24 separates the sync signal from the reproduced video signal. The reproduction signal processing circuit 25 performs reproduction signal processing such as time axis correction and dropout compensation on the reproduction video signal based on the sync separation output from the second sync separation circuit 24, and the D / A converter 26 performs digital signal processing. When D / A is converted to an analog signal and output, a good reproduced video signal can be obtained.

In the first embodiment, the delay time of the delay element 30 is set to τ corresponding to the PCM audio signal area period, the PCM audio signal is multiplexed in the vertical blanking period of the recorded video signal, and the PCM is reproduced at the time of reproduction. PC in the audio signal area
The case where the M audio signal is switched to the reproduced FM video signal before the τ period of the previous field and FM demodulation has been described, but the delay time of the delay element 30 is not limited to this, and the signal in the PCM audio signal area is If it is the delay time for switching to the reproduced FM video signal other than the audio signal area,
The same effect as that of the above embodiment is obtained.

Further, in the above-mentioned first embodiment, when the reproduction is performed as shown in FIG.
The case where the PCM audio signal mixed with the reproduced FM video signal shown in (a) is directly processed as the reproduction signal has been described. For example, in the output of the limiter 19, the FM video signal and the PCM audio signal in the reproduction signal are shown in FIG. Even if it is configured to be separated as in b), the FM
The reproduced video signal after demodulation becomes noise in the PCM audio signal area as shown in FIGS. 26 (c) and 25.
Therefore, as in the above-described embodiment, the reproduced FM video signal (FIG. 4B) in the video signal area of the switch circuit 31 is changed to the PCM audio signal area based on the PCM area signal output from the PCM area signal generator 29. Playback F above
With the configuration in which the output (FIG. 4C) obtained by delaying the M video signal by τ by the delay element 30 is selected and switched, the same effect as that of the above-described embodiment is obtained.

In the first embodiment, the end timing of the PCM audio signal area in the reproduced signal is detected by the PCM area signal generator 29, and the start time of the next PCM audio signal area is predicted from the detection result. P depending on configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal, for example.

In the first embodiment, the PCM audio signal is switched by the switch 8 during the vertical blanking period of the FM video signal.
Although the case of switching and recording in 9 has been described, the present invention is not limited to this, and for example, the PCM audio signal may be divided and switched and inserted in the horizontal blanking period. Further, in a VTR for recording / reproducing by dividing a video signal of one field into a plurality of segments as shown in FIG. 5 (FIG. 5 shows a case of two segment division), each segment blanking period and vertical blanking are performed. Even when the PCM audio signal of one field is divided and inserted in the period and the recording / reproduction is performed, the reproduction F in the reproduction signal is reproduced at the time of reproduction.
Identifying a region of the PCM audio signal mixed with the M video signal and generating a control signal indicating the PCM audio signal region,
As long as the switch circuit 31 is switched based on the control signal, a recording format for recording a PCM audio signal during the segment blanking period may be used, and the same effect as that of the first embodiment can be obtained.

In the first embodiment, the magnetic tape is 18
Although the case of recording in one field and one track by winding 0 ° is shown, the winding angle and the recording format are not limited to this. It may be recorded.

Example 2. Further, in the above-described first embodiment, the FM
The case where the modulated video signal is recorded on the magnetic tape by the rotary head and applied to the magnetic recording / reproducing device (VTR) has been described, but the digital audio signal is time-division multiplexed and recorded on the FM modulated video signal. It may be any device that reproduces, for example, a video signal recording / reproducing device that FM-modulates a video signal to record / reproduce it on a disc-shaped recording medium as in the second embodiment shown in FIG. 6, or a laser disc (LD). Also in other video signal recording / reproducing apparatus such as a magneto-optical disk, the same effect as that of the above-described embodiment can be obtained.

Example 3. In the above embodiment, the delay element 30
Is set to τ corresponding to the period of the PCM audio signal region, and the reproduced FM video signal before the period τ of the field preceding the blanking period of the PCM ¥ audio signal is switched in the PCM audio signal region for FM demodulation. In the case of the PCM audio signal, the delay element 32 having a delay time corresponding to one horizontal scanning period (hereinafter, referred to as 1H) of the video signal is used as in the third embodiment shown in FIG. The same effect as in the above embodiment can be obtained even if the area signal is switched by the switch circuit 31 to the reproduced FM video signal in which the data of the last line of the previous field of the blanking period in which the PCM audio signal is inserted is repeatedly reproduced and FM demodulated. Play.

At this time, the switch circuit 31 selects the reproduced FM video signal output from the limiter 19 in the video signal area based on the PCM area signal from the PCM area signal generator 29 and sends it to the FM demodulator 20 as it is. , On the other hand, P
In the CM audio signal area, switching is performed so as to select the output of the delay element 32 having a delay time of 1H. From the delay element 32, P
Since the reproduced FM video signal, which is the data of the last line of the previous field of the CM audio signal area, is repeatedly output, the PCM is reproduced in the reproduced signal output from the switch circuit 31.
The signal in the audio signal area is a signal in which the reproduced FM video signal, which is the data of the last line of the previous field, is repeated.
The output of the switch circuit 31 is fed to the FM demodulator 20.
FM demodulation is performed with the de-emphasis circuit 21, and the high-frequency component emphasized by the pre-emphasis circuit 5 in the recording circuit is attenuated by the de-emphasis circuit 21 to obtain a reproduced video signal in which high-frequency noise is reduced. The area signal is repeatedly replaced with the reproduced video signal of the last line of the previous field. Therefore, the reproduced video signal can be accurately separated and the clamp circuit 22 operates normally. Further, since the synchronization signal is added to the signal in the PCM audio signal area, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

In the third embodiment, the delay time of the delay element 32 is set to 1H, the PCM audio signal is multiplexed in the vertical blanking period of the recorded video signal, and the PCM audio signal in the PCM audio signal area is reproduced at the time of reproduction. The case where the reproduced FM video signal of the last line of the field is repeatedly replaced and FM demodulated has been described. However, the delay time of the delay element 32 is not limited to this, and may be a delay time of 2H or more. If the configuration is such that the reproduced FM video signal of the previous field other than the PCM audio signal area is repeatedly replaced with the signal, the same effect as that of the above-described embodiment is obtained.

Further, in the above-mentioned third embodiment, when reproducing is performed as shown in FIG.
The case where the PCM audio signal mixed with the reproduced FM video signal shown in (a) is directly processed as the reproduction signal has been described. For example, in the output of the limiter 19, the FM video signal and the PCM audio signal in the reproduction signal are shown in FIG. Even if it is configured to be separated as in b), the FM
The reproduced video signal after demodulation becomes noise in the PCM audio signal area as shown in FIGS. 26 (c) and 25.
Therefore, as in the above embodiment, the reproduced FM video signal is output in the video signal area of the switch circuit 31 and the reproduced FM video signal is output in the PCM audio signal area based on the PCM area signal output from the PCM area signal generator 29. With the configuration in which the output delayed by 1H is selected by the delay element 32 and switched, the same effect as that of the above-described embodiment is obtained.

In the third embodiment, the PCM area signal generator 29 detects the end timing of the PCM audio signal area in the reproduced signal and predicts the start time of the next PCM audio signal area from the detection result. P depending on configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal, for example.

In the third embodiment, the PCM audio signal is switched by the switch 8 during the vertical blanking period of the FM video signal.
Although the case of switching and recording in 9 has been described, the present invention is not limited to this, and for example, the PCM audio signal may be divided and switched and inserted in the horizontal blanking period. Further, in a VTR for recording / reproducing by dividing a video signal of one field into a plurality of segments as shown in FIG. 5 (FIG. 5 shows a case of two segment division), each segment blanking period and vertical blanking are performed. Even when the PCM audio signal of one field is divided and inserted in the period and the recording / reproduction is performed, the reproduction F in the reproduction signal is reproduced at the time of reproduction.
Identifying a region of the PCM audio signal mixed with the M video signal and generating a control signal indicating the PCM audio signal region,
As long as the switch circuit 31 is switched based on the control signal, a recording format for recording the PCM audio signal during the segment blanking period may be used, and the same effect as that of the above embodiment can be obtained.

In the third embodiment, the magnetic tape is 18
Although the case of recording in one field and one track by winding 0 ° is shown, the winding angle and the recording format are not limited to this. It may be recorded.

Example 4. Further, in the above-described third embodiment, the FM
The case where the modulated video signal is recorded on the magnetic tape by the rotary head and applied to the magnetic recording / reproducing device (VTR) has been described, but the digital audio signal is time-division multiplexed and recorded on the FM modulated video signal. It may be any device that reproduces, for example, a video signal recording / reproducing device that FM-modulates a video signal to record / reproduce it on a disc-shaped recording medium, as in the fourth embodiment shown in FIG. 8, or a laser disc (LD). Also in other video signal recording / reproducing apparatus such as a magneto-optical disk, the same effect as that of the above-described embodiment can be obtained.

Example 5. Further, FIG. 9 shows a fifth embodiment of the present invention.
2 is a block diagram of a VTR according to the present invention. In the figure, the recording systems 1 to 13 and the reproducing systems 16 to 26 are exactly the same as those of the above-mentioned conventional device, and therefore detailed description thereof will be omitted.

A PCM 33 detects the PCM voice signal of one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling processing, error correction processing and the like to restore and output the original voice signal. A decoder 34 identifies a PCM audio signal area in the reproduced signal in the PCM decoder 33 and generates a PCM area signal indicating the PCM audio signal area. A PCM area signal generator 35 superimposes on a gray level after FM demodulation, for example. An FM signal generator for generating and outputting an FM signal (carrier frequency is f _c ) which becomes a signal having a constant frequency f _p and an amplitude B, and 36 is a PCM region output from the PCM region signal generator 34. A switch circuit for switching between the reproduction signal output from the limiter 19 and the output from the FM signal generator 35 based on the signal. A.

Next, the operation will be described. During recording, the input video signal is A / D converted by the A / D converter 1, and then, in the recording signal processing circuit 3, blanking data is generated based on the sync separation output from the first sync separation circuit 2. Recording signal processing such as insertion is performed. The recording signal processing circuit 3 also generates and outputs a timing pulse for inserting the PCM audio signal into the FM video signal. The output of the recording signal processing circuit 3 is converted from a digital signal to an analog signal by the D / A converter 4 and sent to the pre-emphasis circuit 5. The pre-emphasis circuit 5 emphasizes the high frequency component of the video signal and outputs it to the FM modulator 6, and the FM modulator 6 FM-modulates the video signal.
On the other hand, the audio signal is input to the PCM encoder 7, subjected to shuffling processing, addition of error correction code, etc., and then the digital audio signal of one field period is converted into the digital audio signal based on the timing pulse output from the recording signal processing circuit 3. F
The time base compression processing is performed to insert the FM video signal output from the M modulator 6 in the vertical blanking period, and the signal is digitally modulated and output.

Thereafter, the PCM audio signal output from the PCM encoder 7 in the one field period is FM.
The recording amplifier 1 is inserted in the vertical blanking period of the modulated video signal at a timing as shown in FIG.
It is output to 1. A timing pulse output from the recording signal processing circuit 3 is sent to the switches 8 and 9, and an FM video signal and a PCM audio signal are switched by the adder 10 to generate a recording signal. Then, in the recording amplifier 11, the FM video signal and the PCM which are the above recording signals.
The audio signal is amplified and recorded on the magnetic tape 13 by the rotary heads 12a and 12b. At this time, the magnetic tape 13 is tightly wound around the rotary drum 14 by 180 ° as shown in FIG. Only during the period when the rotary head is in contact with the magnetic tape 13. Therefore, the recording pattern on the magnetic tape 13 is divided into two areas a and b as shown in FIG. 20, and the recording signal of one field is recorded on one track. In the figure, a indicates a track recorded by the rotary head 12a, and b indicates a track recorded by the rotary head 12b. Also, the PCM audio signal is F
Since the signals are time-division multiplexed and recorded during the vertical blanking period of the M video signal, the portion where the PCM audio signal is recorded is the shaded portion. The recording operation up to this point is the same as in the conventional example.

At the time of reproduction, the rotary heads 12a and 12b reproduce from the magnetic tape 13 the PCM audio signal mixed with the reproduced FM video signal at the time of recording as a reproduction signal, which is amplified by the head amplifiers 16a and 16b. The reproduced signals output from the head amplifiers 16a and 16b are sent to the head switching circuit 17 as shown in FIG.
The reproduction signal from the rotary head that is in contact with the magnetic tape 13 is selected and switched based on the head switching signal as shown in FIG. 11, and one reproduction signal (FIG. 21C) is obtained. The reproduction signal from the head switching circuit 17 is sent to the reproduction equalizer 18 and the PCM decoder 34. In the PCM decoder 34, the PCM of one field period inserted in the vertical blanking period of the reproduction signal
The voice signal is detected, and error correction, deshuffling processing, error correction processing and the like are performed to restore the original voice signal and output it. On the other hand, the reproduction equalizer 18 compensates the frequency characteristic of the reproduction FM video signal of the input reproduction signal and sends it to the limiter 19, which removes the amplitude fluctuation component of the reproduction FM video signal.

By the way, when the FM demodulator 20 directly demodulates the reproduced FM video signal and the PCM audio signal multiplexed in the vertical blanking period as in the conventional example,
The reproduced video signal waveform in the PCM audio signal area is shown in FIG.
As shown in (a), a signal waveform like noise is output.

Therefore, in the FM signal generator 35, for example, after FM demodulation, an FM modulated signal (carrier frequency f _c ) which is a signal of constant frequency f _p and amplitude B superimposed on the gray level is generated and output. , This FM signal generator 35
And the reproduction signal output from the limiter 19 as P
The PCM area signal indicating the CM audio signal area is input to the switch circuit 36 capable of switching the output and switched.
The waveform of the reproduced video signal after FM demodulating the output of the switch circuit 36 becomes a signal as shown in FIG.
The switch circuit 36 includes a PC in the PCM decoder 33.
The PCM domain signal generated by the M domain signal generator 34 is sent. The PCM area signal generator 34 detects the end timing of the PCM audio signal area of the reproduced signal in the PCM decoder 33 and predicts the start time of the next PCM audio signal area from the detection result. A PCM area signal indicating the audio signal area is generated.

In the PCM domain signal generator 34, the PC
When a pulse indicating the M audio signal area and the video signal area is generated and sent to the switch circuit 36, the switch circuit 36
The reproduction signal sent from the limiter 19 (FIG. 11A) is selected in the video signal area period, and the output of the FM signal generator 35 (FIG. 11B) is selected and output in the PCM audio signal area period. Therefore, the output of the switch circuit 36 becomes as shown in FIG. 11C, and the output of the switch circuit 36 is sent to the FM demodulator 20 for FM demodulation and the reproduced video signal after passing through the de-emphasis circuit 21. PC
The signal in the M audio signal region is a signal of frequency f _p and amplitude B superimposed on the gray level as shown in FIG.

By doing so, the signal in the PCM audio signal region in the FM-demodulated reproduced video signal can be made into a signal of constant frequency f _p and amplitude B which is superimposed on the gray level, so that the video signal is synchronously separated. Can be done accurately. Moreover, since the signal switched in the PCM audio signal area is not the signal of only the DC level, the sag can be reduced.

The reproduced signal output from the switch circuit 36 is FM demodulated by the FM demodulator 20 and the pre-emphasis circuit 5 in the recording circuit by the de-emphasis circuit 21.
By attenuating the high frequency component emphasized in step 1, a reproduced video signal in which high frequency noise is reduced as shown in FIG. 10 is obtained. Then, the reproduced video signal output from the de-emphasis circuit 21 is input to the clamp circuit 22, where the sync signal tip of the reproduced video signal is clamped to a predetermined DC voltage level. After that, the reproduced video signal is sent to the A / D converter 2
At 3, the analog signal is A / D converted into a digital signal and sent to the reproduction signal processing circuit 25. The second sync separation circuit 24 separates the sync signal from the reproduced video signal. In the reproduction signal processing circuit 25, reproduction signal processing such as time axis correction and dropout compensation is performed on the reproduction video signal based on the synchronization separation output from the second synchronization separation circuit 24, and the output is a D / A converter. When D / A conversion is performed at 26, a good reproduced video signal is obtained.

In the fifth embodiment, the FM signal generator 3
5, a case has been described in which an FM signal (carrier frequency f _c ) which becomes a signal of constant frequency f _p and amplitude B superimposed on the gray level after FM demodulation is generated and output, but the present invention is not limited to this. Similar to the above-described embodiment, if an FM-modulated signal other than a constant DC level signal having a certain frequency that reduces sag is generated between the pedestal level and the white level after FM demodulation. Produce an effect.

In the fifth embodiment, the end timing of the PCM audio signal area in the reproduced signal is detected by the PCM area signal generator 34, and the start time of the next PCM audio signal area is predicted from the detection result. P depending on configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal, for example.

In the fifth embodiment, the reproduction F
The case has been described in which the PCM audio signal mixed with the M video signal is directly demodulated and processed as a reproduction signal by FM demodulation.
For example, even when the output of the limiter 19 is configured such that the FM video signal and the PCM audio signal in the reproduction signal are separated as shown in FIG. 12B, the reproduction video signal after FM demodulation is shown in FIG. As shown in FIG. 25C and FIG. 25, it becomes noise in the PCM audio signal area. Therefore, as in the above-described embodiment, the reproduced FM video signal (FIG. 12B) in the video signal area of the switch circuit 36 is changed to the PCM audio signal area based on the PCM area signal output from the PCM area signal generator 34. Then, the output (FIG. 12 (c)) of the FM signal generator is selected and switched to achieve the same effect as that of the fifth embodiment.

In the fifth embodiment, the PCM audio signal is switched by the switch 8 during the vertical blanking period of the FM video signal.
Although the case of switching and recording in 9 has been described, the present invention is not limited to this, and for example, the PCM audio signal may be divided and switched and inserted in the horizontal blanking period. Further, in a VTR for recording / reproducing by dividing a video signal of one field into a plurality of segments as shown in FIG. 5 (FIG. 5 shows a case of two segment division), each segment blanking period and vertical blanking are performed. Even when the PCM audio signal of one field is divided and inserted in the period and the recording / reproduction is performed, the reproduction F in the reproduction signal is reproduced at the time of reproduction.
Identifying a region of the PCM audio signal mixed with the M video signal and generating a control signal indicating the PCM audio signal region,
As long as the switch circuit is switched based on the control signal, a recording format for recording the PCM audio signal during the segment blanking period may be used, and the same effect as that of the third embodiment can be obtained.

In the fifth embodiment, the magnetic tape is 18
Although the case of recording in one field and one track by winding 0 ° is shown, the winding angle and the recording format are not limited to this. It may be recorded.

Example 6. In addition, in the fifth embodiment, the FM
The case where the modulated video signal is recorded on the magnetic tape by the rotary head and applied to the magnetic recording / reproducing device (VTR) has been described, but the digital audio signal is time-division multiplexed and recorded on the FM modulated video signal. Any device may be used as long as it is a reproducing device, for example, a video signal recording / reproducing device for FM-modulating a video signal to record / reproduce on / from a disc-shaped recording medium as in the sixth embodiment shown in FIG. 13, or a laser disc (LD). Also in other video signal recording / reproducing apparatus such as a magneto-optical disk, the same effect as that of the above-described embodiment can be obtained.

Example 7. 14 is a block diagram of a VTR according to the seventh embodiment of the present invention. In the figure, the recording systems 1 to 13 and the reproducing systems 16 to 26 are exactly the same as those of the above-mentioned conventional apparatus, and therefore detailed description thereof will be omitted.

Numeral 37 is a PCM which detects the PCM voice signal of one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling processing, error correction processing and the like to restore and output the original voice signal. The decoder 38 is a PCM area signal generator for accurately discriminating the PCM audio signal area of the reproduced signal in the PCM decoder 37 and generating a PCM area signal indicating the PCM audio signal area. 39 is an output from the head amplifier 16a. A delay element I for delaying a reproduction signal by a delay period τ is a delay element II for delaying a reproduction signal which is an output from the head amplifier 16b by τ, and 41 and 42 are outputs from the PCM area signal generator 38. The switch circuit is capable of switching control based on a certain PCM area signal.

Next, the operation will be described. During recording, the input video signal is A / D converted by the A / D converter 1, and then, in the recording signal processing circuit 3, blanking data is generated based on the sync separation output from the first sync separation circuit 2. Processing such as insertion is performed to convert to a recorded video signal.
The recording signal processing circuit 3 converts the FM video signal into a PC.
A timing pulse for inserting the M audio signal is also generated and output. The output of the recording signal processing circuit 3 is D
The / A converter 4 converts the digital signal into an analog signal and sends it to the pre-emphasis circuit 5. Puri
The emphasis circuit 5 emphasizes the high frequency component of the video signal and outputs it to the FM modulator 6, and the FM modulator 6 FM-modulates the video signal. On the other hand, the audio signal is input to the PCM encoder 7, subjected to shuffling processing, addition of error correction code, etc., and then the digital audio signal of one field period is converted into the digital audio signal based on the timing pulse output from the recording signal processing circuit 3. The time axis compression process is performed for inserting the FM video signal output from the FM modulator 6 in the vertical blanking period, and the signal is digitally modulated and output.

Thereafter, the PCM audio signal output from the PCM encoder 7 in the one-field period is FM.
The recording amplifier 1 is inserted in the vertical blanking period of the modulated video signal at a timing as shown in FIG.
It is output to 1. A timing pulse output from the recording signal processing circuit 3 is sent to the switches 8 and 9, and an FM video signal and a PCM audio signal are switched by the adder 10 to generate a recording signal. Then, in the recording amplifier 11, the FM video signal and the PCM which are the above recording signals.
The audio signal is amplified and recorded on the magnetic tape 13 by the rotary heads 12a and 12b. At this time, the magnetic tape 13 is strongly wound around the rotary drum 14 by 180 ° as shown in FIG. Only during the period when the rotary head is in contact with the magnetic tape 13. Therefore, the recording pattern on the magnetic tape 13 is divided into two areas a and b as shown in FIG. 21, and the recording signal of one field is recorded on one track. In the figure, a indicates a track recorded by the rotary head 12a, and b indicates a track recorded by the rotary head 12b. Also, the PCM audio signal is F
Since the signals are time-division multiplexed and recorded during the vertical blanking period of the M video signal, the portion where the PCM audio signal is recorded is the shaded portion. The recording operation up to this point is the same as in the conventional example.

At the time of reproduction, the rotary heads 12a and 12b respectively reproduce from the magnetic tape 13 the reproduced FM video signal and the PCM audio signal mixed at the time of recording, and the head amplifier 16
Amplify with a and 16b. Then, the reproduction signals from the rotary heads amplified by the head amplifiers 16a and 16b are switched circuits 41 and 42 and a delay element 39, respectively.
40, and also to the PCM decoder 37. In the PCM decoder 37, the head amplifier 16
PC of one field period inserted in the vertical blanking period in the reproduction signal sent from each of a and 16b.
While detecting the M audio signal, shuffling processing, error correction processing and the like are performed to restore and output the original audio signal.

By the way, when the FM demodulator 20 directly demodulates the reproduced FM video signal and the PCM audio signal multiplexed in the vertical blanking period as in the conventional example,
The reproduced video signal waveform in the PCM audio signal area is shown in FIG.
As shown in (a), a signal waveform like noise is output.

Therefore, the reproduced signal shown in FIG. 15A output from the head amplifier 16a is input to the switch circuit 41 and the delay element I 39, and the reproduced signal shown in FIG. 15B from the head amplifier 16b is inputted into the switch circuit. 42 and the delay element II 40. And the switch circuit 4
By switching between 1 and 42, the signal in the PCM audio signal area in the reproduced video signal after FM demodulation can be changed as shown in FIG.
As described above, the signal is switched to the signal on the line before the PCM audio signal region period of the previous field. The PCM area signal generated by the PCM area signal generator 38 in the PCM decoder 37 is sent to the switch circuits 41 and 42. The PCM area signal generator 38 detects the end timing of the PCM audio signal area of the reproduced signal in the PCM decoder 37 and predicts the start time of the next PCM audio signal area from the detection result. A PCM area signal indicating the PCM audio signal area is generated.

In the PCM domain signal generator 38, the PC
A pulse indicating the M audio signal area and the video signal area is generated and sent to the switch circuits 41 and 42. The switch circuit 41 selects the reproduction signal (FIG. 15A) of the rotary head 12a which is the output of the head amplifier 16a in the video signal area, while the head amplifier 1 is selected in the PCM audio signal area.
6b output signal of the rotary head 16b (FIG. 15).
(B)) is switched to select the output of the delay element II40 delayed by τ period as shown in FIG. Then, the switch circuit 42 selects the reproduction signal of the rotary head 12b (FIG. 15B) which is the output of the head amplifier 16b in the video signal area, while the rotation signal which is the output of the head amplifier 16a in the PCM audio signal area. Head 16a
15 (a) is switched so as to select the output of the delay element I39 delayed by τ period as shown in FIG. 15 (c). The delay element I39 outputs a reproduced FM video signal obtained by delaying the signal of the previous field of the PCM audio signal area in the reproduced signal from the head amplifier 16b by τ, and the delay element II40 outputs the reproduced signal from the head amplifier 16a. 15 outputs the reproduced FM video signal obtained by delaying the signal of the previous field of the PCM audio signal area by .tau.
As shown in (e), the output from the switch circuit 42 is as shown in FIG. 15 (f). Therefore, the signals in the PCM audio signal area in the reproduced signals from the respective heads are in front of the PCM audio signal area. The reproduced FM video signal corresponds to the τ period of the field.

Therefore, the respective outputs of the switch circuits 41 and 42 are input to the head switching circuit 17, and the reproduction signal from the rotary head in contact with the magnetic tape 13 is selected and switched based on the head switching signal.
Assuming one reproduction signal, its output is as shown in FIG. The reproduction signal output from the head switching circuit 17 is sent to the reproduction equalizer 18, where the frequency characteristic of the reproduction FM video signal is compensated and the limiter 1 is used.
Then, the limiter 19 removes the amplitude fluctuation component of the reproduced FM video signal. The output of the limiter 19 is F
When the high-frequency component which is input to the M demodulator 20 and FM-demodulated and emphasized by the pre-emphasis circuit 5 in the recording circuit is attenuated by the de-emphasis circuit 21, a high-frequency component as shown in FIG. A reproduced video signal with reduced noise is obtained. Then, since the signal in the PCM audio signal area is replaced with the reproduced video signal in the previous field, the synchronous separation of the reproduced video signal can be accurately performed, and the operation of the clamp circuit 22 is normally performed. Also, since the synchronization signal is added to the signal in the PCM audio signal area, the PCM
Clamp can be applied even in the audio signal area,
Sags are reduced.

The reproduced video signal output from the de-emphasis circuit 21 is clamped at the tip of the synchronizing signal to a predetermined DC voltage level in the clamp circuit 22, and A
A / D converter 23 converts analog signals into digital signals A
The signal is D / D converted and sent to the reproduction signal processing circuit 25. The second sync separation circuit 24 separates the sync signal from the reproduced video signal. The reproduction signal processing circuit 25 performs reproduction signal processing such as time axis correction and dropout compensation on the reproduction video signal based on the sync separation output from the second sync separation circuit 24, and the D / A converter 26 performs digital signal processing. When D / A is converted to an analog signal and output, a good reproduced video signal can be obtained.

In the seventh embodiment, the delay time of the delay elements 39 and 40 is set to τ corresponding to the PCM audio signal area period, and the reproduced FM video signal before the τ period of the previous field of the PCM audio signal area is set. The case where the switching is performed in the PCM audio signal area has been described, but the delay times of the delay elements 39 and 40 are not limited to this.
If the delay time is such that the signal in the PCM audio signal area is switched to the reproduced FM video signal in the area other than the PCM audio signal area in the previous field, the same effect as that of the above-described embodiment can be obtained.

In the seventh embodiment, the end timing of the PCM audio signal area in the reproduced signal is detected by the PCM area signal generator 38, and the start time of the next PCM audio signal area is predicted from the detection result. P depending on the configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal, for example.

Further, in the above-mentioned seventh embodiment, the reproduction F is performed at the time of reproduction.
The case has been described in which the PCM audio signal mixed with the M video signal is directly processed as a reproduction signal by switching with the switch circuits 41 and 42. 16 (c) and 16 (d), the output of the head switching circuit is shown in FIG. 16 even when the switching circuit is switched based on the PCM region signal by inputting to the switching circuit and the delay element. As shown in (g), the same effect as that of the above-described embodiment is obtained.

In the seventh embodiment, the PCM audio signal is switched by the switch 8 during the vertical blanking period of the FM video signal.
Although the case of switching and recording in 9 has been described, the present invention is not limited to this, and for example, the PCM audio signal may be divided and switched and inserted in the horizontal blanking period. Further, in a VTR for recording / reproducing by dividing a video signal of one field into a plurality of segments as shown in FIG. 5 (FIG. 5 shows a case of two segment division), each segment blanking period and vertical blanking are performed. Even when the PCM audio signal of one field is divided and inserted in the period and the recording / reproduction is performed, the reproduction F in the reproduction signal is reproduced at the time of reproduction.
Identifying a region of the PCM audio signal mixed with the M video signal and generating a control signal indicating the PCM audio signal region,
As long as the switch circuit is switched based on the control signal, a recording format for recording the PCM audio signal during the segment blanking period may be used, and the same effect as that of the above embodiment is obtained.

In the seventh embodiment, the magnetic tape is 18
Although the case of recording in one field and one track by winding 0 ° is shown, the winding angle and the recording format are not limited to this. It may be recorded.

[0079]

As described above, according to the present invention, the PCM
The audio signal is time-division multiplexed in the blanking period of the FM video signal and recorded / reproduced. Based on the PCM area signal indicating the PCM audio signal area during reproduction, the reproduction signal before FM demodulation and this reproduction signal are kept for a certain period τ. A switch circuit for switching the signal delayed by only the above is provided, and the signal in the PCM audio signal area in the reproduced video signal after FM demodulating the output of the switch circuit is prior to the blanking period in which the PCM audio signal is inserted. Since it is configured to replace the reproduced video signal of,
Clamping can be applied even in the PCM audio signal area, sag can be reduced, and good reproduced video signals can be obtained.

As described above, according to the present invention, P
The CM audio signal is time-division multiplexed in the blanking period of the FM video signal and recorded / reproduced. Based on the PCM area signal indicating the PCM audio signal area at the time of reproduction, the reproduced signal before FM demodulation and this reproduced signal are 1 horizontal A switch circuit for switching the signal delayed for the scanning period is provided, and the signal in the PCM audio signal area in the reproduced video signal after FM demodulating the output of the switch circuit is placed before the blanking period in which the PCM audio signal is inserted. Since the reproduced video signal of the last line of the period is replaced with the repeated signal, the reproduced video signal can be accurately separated in synchronization, the PCM audio signal area can be clamped, and the sag can be reduced. It is possible to obtain an excellent reproduced video signal.

As described above, according to the present invention, P
The CM audio signal is time-division multiplexed in the blanking period of the FM video signal, recorded and reproduced, and an FM signal obtained by FM-modulating the reproduction signal and a signal of a constant frequency based on the PCM area signal indicating the PCM audio signal area during reproduction. A switch circuit for switching is provided, and the signal in the PCM audio signal region in the reproduced video signal after FM demodulating the output of the switch circuit becomes a signal of a constant frequency superimposed on the video signal level from the pedestal level to the white level. With this configuration, the reproduction video signal can be accurately separated in synchronization, the operation of the clamp circuit can be performed normally, the sag can be reduced, and an excellent reproduction video signal can be obtained.

As described above, according to the present invention, P
The CM audio signal is time-division multiplexed in the blanking period of the FM video signal and recorded / reproduced. Based on the PCM area signal indicating the PCM audio signal area during reproduction, each reproduction signal from each rotary head and each reproduction signal Is switched by a switch circuit, and the output of each switch circuit is selected and switched by the head switching circuit to switch the output of the head switching circuit to F
Since the signal in the PCM audio signal area in the reproduced video signal after M demodulation is replaced with the reproduced video signal in the period before the blanking period in which the PCM audio signal is inserted, the synchronous separation of the reproduced video signal is performed. Do exactly, P
Clamping can be applied even in the CM audio signal area, sag can be reduced, and a good reproduced video signal can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a magnetic recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram showing an example of an output waveform of a reproduced video signal after FM demodulation according to the embodiment of the present invention.

FIG. 3 is a waveform diagram for explaining operations of the PCM region signal generator, the delay element and the switch circuit according to the first embodiment of the present invention.

FIG. 4 is a waveform diagram for explaining the operation of the delay element and the switch circuit when the FM video signal and the PCM audio signal of the reproduction signal are separated and processed in the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of a case where a PCM audio signal is time-division multiplexed in each segment blanking period of an FM video signal in a VTR of 2-segment recording.

FIG. 6 is a block diagram showing a video signal recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 7 is a block diagram showing a magnetic recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 8 is a block diagram showing a video signal recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a block diagram showing a magnetic recording / reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a waveform chart showing an example of an output waveform of a reproduced video signal in Example 5 of the present invention.

FIG. 11 is a waveform diagram for explaining operations of the PCM region signal generator, the FM signal generator, and the switch circuit according to the fifth embodiment of the present invention.

FIG. 12 is a waveform diagram for explaining the operations of the FM signal generator and the switch circuit when the FM video signal and the PCM audio signal of the reproduction signal are separated and processed in the fifth embodiment of the present invention.

FIG. 13 is a block diagram showing a video signal recording / reproducing device according to a sixth embodiment of the present invention.

FIG. 14 is a block diagram showing a magnetic recording / reproducing apparatus according to Example 7 of the present invention.

FIG. 15 is a waveform diagram for explaining the operation of the PCM region signal generator, each delay element, and each switch circuit in the seventh embodiment of the present invention.

FIG. 16 is a waveform diagram for explaining the operation of each delay element and the switch circuit when the FM video signal and the PCM audio signal of the reproduction signal are separated and processed in the seventh embodiment of the present invention.

FIG. 17 is a block diagram showing an example of a conventional magnetic recording / reproducing apparatus.

FIG. 18 is a view of the rotary drum as viewed from above.

FIG. 19 is a diagram showing an example of a case where a PCM audio signal is time-division multiplexed during a blanking period of an FM video signal.

FIG. 20 is a diagram showing a recording pattern on a magnetic tape.

FIG. 21 is a diagram for explaining the operation of the head switching circuit.

FIG. 22 is a diagram for explaining operations of a reproduction equalizer and a limiter.

FIG. 23 is a characteristic diagram showing an example of frequency characteristics of a reproduction equalizer.

FIG. 24 is a characteristic diagram showing an FM video signal band and a PCM audio signal band during reproduction.

FIG. 25 is a waveform diagram showing an output waveform of a reproduced video signal after FM demodulation in the conventional magnetic recording / reproducing apparatus.

FIG. 26 is a diagram showing a case where an FM video signal and a PCM audio signal of a reproduction signal are separated and processed in a conventional magnetic recording / reproducing apparatus,
It is a waveform diagram which shows the output waveform of the reproduction | regeneration video signal after FM demodulation.

[Explanation of symbols]

 29, 34, 38 PCM area signal generator 30, 32 Delay element 31, 36, 41, 42 Switch circuit 35 FM signal generator 39 Delay element I 40 Delay element II 17 Head switching circuit

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[Procedure amendment]

[Submission date] March 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Reference numerals 16a and 16b denote the rotary heads 12a.
And a head amplifier for amplifying the reproduction signal from 12b,
Reference numeral 17 denotes a head switching circuit for switching the outputs from the head amplifiers 16a and 16b based on a head switching signal,
Reference numeral 18 is a reproduction equalizer for compensating the frequency characteristic of the reproduction FM video signal, 19 is a limiter for removing the amplitude fluctuation component of the reproduction FM video signal output from the reproduction equalizer 18, and 20.
Is an FM demodulator, 21 is a de-emphasis circuit having the inverse characteristic of the pre-emphasis circuit 5 , 22 is a clamp circuit, 23 is an A / D converter for converting a reproduced video signal from an analog signal to a digital signal, 24 Is a second sync separation circuit that separates the sync signal from the reproduced video signal, and 25 is a reproduction such as time-axis correction and dropout compensation of the reproduced video signal based on the sync separation signal output from the second sync separation circuit 24. A reproduction signal processing circuit for performing signal processing, 26 is D
An A / A converter 27 is a PCM decoder, which detects the PCM audio signal of the one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling process, error correction process, etc. The audio signal is restored and output.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Next, the operation during reproduction will be described. The reproduced FM video signal reproduced by the rotary heads 12a and 12b and the PCM audio signal mixed at the time of recording are amplified by the head amplifiers 16a and 16b, respectively. The reproduction signals output from the head amplifiers 16a and 16b are selected by the head switching circuit 17 from reproduction signals from the rotary head that is in contact with the magnetic tape 13 as shown in FIG. 21, based on the head switching signals. Then, the signals are switched to one reproduction signal (FIG. 21 (c)). And
The reproduction signal from the head switching circuit 17 is sent to the reproduction equalizer 18 and the PCM decoder 27. In the PCM decoder 27, the PCM of the one field period inserted in the vertical blanking period of the reproduction signal.
The voice signal is detected, and error correction, deshuffling processing, error correction processing and the like are performed to restore the original voice signal and output it.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Next, the operation during reproduction will be described. The reproduced FM video signal reproduced from the rotary heads 12a and 12b and the PCM audio signal mixed at the time of recording are the head amplifier 1
It is amplified by 6a and 16b. Then, the reproduction signals output from the head amplifiers 16a and 16b are
In the head switching circuit 17, the reproduction signal from the rotary head that is in contact with the magnetic tape 13 is selected and switched based on the head switching signal as shown in FIG. 21, and one reproduction signal (FIG. 21C) is selected. Become. The reproduction signal from the head switching circuit 17 is sent to the reproduction equalizer 18 and the PCM decoder 28. The PCM decoder 28 detects the PCM voice signal of one field period inserted in the vertical blanking period of the reproduced signal and performs error correction, deshuffling process, error correction process, etc. to restore the original voice signal and output it. . On the other hand, the reproduction equalizer 18 compensates the frequency characteristic of the reproduction FM video signal of the input reproduction signal and sends it to the limiter 19, which removes the amplitude fluctuation component of the reproduction FM video signal.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

In the PCM domain signal generator 29, the PC
A pulse indicating the M audio signal area and the video signal area is generated and sent to the switch circuit 31. In the switch circuit 31,
In the video signal area, the reproduced signal output from the limiter 19 shown in FIG. 3A is selected, while in the PCM audio signal area, the output of the delay element 30 having a delay time τ as shown in FIG. 3B is selected. Switch to do so. From the delay element 30, P
Since the reproduced FM signal obtained by delaying the signal in the previous field of the CM audio signal area by τ is output, the signal in the PCM audio signal area is delayed by τ period in the previous field as shown in FIG. It becomes a reproduced FM signal of a part .

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

Therefore, the reproduced FM signal output from the switch circuit 31 to be input to the FM demodulator 20 has the PCM audio signal inserted in the PCM audio signal area as shown in FIG. 3C. Since the reproduced FM signal obtained by delaying the signal in the previous field of the vertical blanking period by τ period is inserted, the output of the switch circuit 31 is FM demodulated by the FM demodulator 20 and the pre-emphasis circuit 21 stores the pre-recorded signal in the recording circuit. When the high frequency component emphasized by the emphasis circuit 5 is attenuated, a reproduced video signal in which high frequency noise is reduced as shown in FIG. 2B is obtained. And P
Since the signal of the CM audio signal region will be replaced by the playback video signal of the previous field, the sync separator of the reproduced video signal is accurately performed, the operation of the clamp circuit 22 is to be performed normally. Further, since the synchronization signal is added to the signal in the PCM audio signal area, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

In the first embodiment, the end timing of the PCM audio signal area in the reproduced signal is detected by the PCM area signal generator 29, and the start time of the next PCM audio signal area is predicted from the detection result. P depending on configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal , for example.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Item name to be corrected] 0040

[Correction method] Change

[Correction content]

Example 3. In the above embodiment, the delay element 30
Delay time of the τ corresponds to the PCM audio signal area period, to FM demodulation by switching the playback FM video signal of τ period previous to the previous field blanking period with a PC M sound voice signals in PCM audio signal area Although the case of the configuration has been described, as in the third embodiment shown in FIG.
By using the delay element 32 having a delay time corresponding to a horizontal scanning period (hereinafter referred to as 1H), the signal in the PCM audio signal area is switched by the switch circuit 31 in the field before the blanking period in which the PCM audio signal is inserted. Even if the configuration is such that the data of the final line is switched to the replayed FM video signal and FM demodulated, the same effect as that of the above-described embodiment can be obtained.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

In the third embodiment, the PCM area signal generator 29 detects the end timing of the PCM audio signal area in the reproduced signal and predicts the start time of the next PCM audio signal area from the detection result. P depending on configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal , for example.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction content]

At the time of reproduction, the rotary heads 12a and 12b reproduce from the magnetic tape 13 the PCM audio signal mixed with the reproduced FM video signal at the time of recording as a reproduction signal, which is amplified by the head amplifiers 16a and 16b. The reproduced signals output from the head amplifiers 16a and 16b are based on the reproduced signals from the rotary head contacting the magnetic tape 13 in the head switching circuit 17 as shown in FIG. Select and switch to one reproduction signal (FIG. 21 (c)). And
Reproduced signal from the head switching circuit 17 is fed to a PCM decoder 3 3 together and sent to the reproduction equalizer 18. In PCM decoder 3 3 detects a PCM audio signal of one field period which is inserted in a vertical blanking period of the reproduced signal, error correction, deshuffling process, to restore the subjecting original audio signal error correcting process like output . On the other hand, the reproduction equalizer 18 compensates the frequency characteristic of the reproduction FM video signal of the input reproduction signal and sends it to the limiter 19, which removes the amplitude fluctuation component of the reproduction FM video signal.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction content]

In the fifth embodiment, the end timing of the PCM audio signal area in the reproduced signal is detected by the PCM area signal generator 34, and the start time of the next PCM audio signal area is predicted from the detection result. P depending on configuration
The case where a CM area signal is generated has been described.
The method of generating the M region signal is not limited to this, and may be generated from the timing of the head switching signal , for example.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction content]

In the fifth embodiment, the PCM audio signal is switched by the switch 8 during the vertical blanking period of the FM video signal.
Although the case of switching and recording in 9 has been described, the present invention is not limited to this, and for example, the PCM audio signal may be divided and switched and inserted in the horizontal blanking period. Further, in a VTR for recording / reproducing by dividing a video signal of one field into a plurality of segments as shown in FIG. 5 (FIG. 5 shows a case of two segment division), each segment blanking period and vertical blanking are performed. Even when the PCM audio signal of one field is divided and inserted in the period and the recording / reproduction is performed, the reproduction F in the reproduction signal is reproduced at the time of reproduction.
Identifying a region of the PCM audio signal mixed with the M video signal and generating a control signal indicating the PCM audio signal region,
As long as the switch circuit is switched based on the control signal, a recording format for recording the PCM audio signal during the segment blanking period may be used, and the same effect as that of the fifth embodiment can be obtained.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction content]

Thereafter, the PCM audio signal output from the PCM encoder 7 in the one-field period is FM.
The recording amplifier 1 is inserted in the vertical blanking period of the modulated video signal at a timing as shown in FIG.
It is output to 1. A timing pulse output from the recording signal processing circuit 3 is sent to the switches 8 and 9, and an FM video signal and a PCM audio signal are switched by the adder 10 to generate a recording signal. Then, in the recording amplifier 11, the FM video signal and the PCM which are the above recording signals.
The audio signal is amplified and recorded on the magnetic tape 13 by the rotary heads 12a and 12b. At this time, the magnetic tape 13 is strongly wound around the rotary drum 14 by 180 ° as shown in FIG. 18 , and even if the recording current is constantly flowing to the rotary heads 12a and 12b, the data is recorded on the magnetic tape 13. Only during the period when the rotary head is in contact with the magnetic tape 13. Therefore, the recording pattern on the magnetic tape 13 is divided into two areas a and b as shown in FIG. 20 , and the recording signal of one field is recorded on one track. In the figure, a indicates a track recorded by the rotary head 12a, and b indicates a track recorded by the rotary head 12b. Also, the PCM audio signal is F
Since the signals are time-division multiplexed and recorded during the vertical blanking period of the M video signal, the portion where the PCM audio signal is recorded is the shaded portion. The recording operation up to this point is the same as in the conventional example.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction content]

In the PCM domain signal generator 38, the PC
A pulse indicating the M audio signal area and the video signal area is generated and sent to the switch circuits 41 and 42. The switch circuit 41 selects the reproduction signal (FIG. 15A) of the rotary head 12a which is the output of the head amplifier 16a in the video signal area, while the head amplifier 1 is selected in the PCM audio signal area.
6b output signal of the rotary head 16b (FIG. 15).
(B)) is switched to select the output of the delay element II40 delayed by τ period as shown in FIG. Then, the switch circuit 42 selects the reproduction signal of the rotary head 12b (FIG. 15B) which is the output of the head amplifier 16b in the video signal area, while the rotation signal which is the output of the head amplifier 16a in the PCM audio signal area. Head 16a
15 (a) is switched so as to select the output of the delay element I39 delayed by τ period as shown in FIG. 15 (c). From the delay element I39, is output reproduced FM video signal a signal of the previous field of the PCM audio signal area delayed by τ in the reproduced signal from the head amplifier 16 a, from the head amplifier 16 b from the delay element II40 The output from the switch circuit 41 is shown in FIG.
As shown in (e), the output from the switch circuit 42 is as shown in FIG. 15 (f). Therefore, the signals in the PCM audio signal area in the reproduced signals from the respective heads are in front of the PCM audio signal area. The reproduced FM video signal corresponds to the τ period of the field.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Name of item to be corrected] 0072

[Correction method] Change

[Correction content]

Therefore, the respective outputs of the switch circuits 41 and 42 are input to the head switching circuit 17,
When the reproduction signal from the rotary head that is in contact with the magnetic tape 13 is selected and switched based on the head switching signal to make one reproduction signal, the output is as shown in FIG. 15 (g). Then, the reproduction signal output from the head switching circuit 17 is sent to the reproduction equalizer 18, where the frequency characteristic of the reproduction FM video signal is compensated and sent to the limiter 19, and the amplitude of the reproduction FM video signal is sent by the limiter 19. Remove the fluctuation component. The output of the limiter 19 is then input to the FM demodulator 20 for FM demodulation, and the de-emphasis circuit 21 attenuates the high-frequency component emphasized by the pre-emphasis circuit 5 in the recording circuit. A reproduced video signal in which high-frequency noise is reduced as shown in b) can be obtained. Then, since the signal in the PCM audio signal area is replaced with the reproduced video signal in the previous field, the synchronous separation of the reproduced video signal can be accurately performed, and the operation of the clamp circuit 22 is normally performed. Further, since the synchronization signal is added to the signal in the PCM audio signal area, the clamp can be applied also in the PCM audio signal area, and the sag can be reduced.

[Procedure Amendment 15]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 10

[Correction method] Change

[Correction content]

FIG. 10 is a waveform chart showing an example of an output waveform of a reproduced video signal in Example 5 of the present invention.

[Procedure 16]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 17]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure 18]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure Amendment 19]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure amendment 20]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

[Procedure correction 21]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

[Procedure correction 22]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure amendment 23]

[Document name to be corrected] Drawing

[Correction target item name] Figure 9

[Correction method] Change

[Correction content]

[Figure 9]

[Procedure amendment 24]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 13

[Correction method] Change

[Correction content]

[Fig. 13]

[Procedure Amendment 25]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14

[Procedure Amendment 26]

[Document name to be corrected] Drawing

[Correction target item name] Figure 15

[Correction method] Change

[Correction content]

FIG. 15

[Procedure Amendment 27]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 16

[Correction method] Change

[Correction content]

FIG. 16

[Procedure correction 28]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 17

[Correction method] Change

[Correction content]

FIG. 17

[Procedure correction 29]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 20

[Correction method] Change

[Correction content]

FIG. 20

[Procedure amendment 30]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 21

[Correction method] Change

[Correction content]

FIG. 21

[Procedure 31]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 26

[Correction method] Change

[Correction content]

FIG. 26

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H04N 7/08 101 9070-5C

Claims (3)

[Claims] 1. A video signal recording / reproducing apparatus for FM-modulating a video signal and time-division multiplexing and recording / reproducing a digital audio signal in the blanking period of the FM-modulated recording video signal. The area signal generating means for discriminating the area of the digital audio signal and generating the control signal indicating the area of the digital audio signal, the delay means for delaying the reproduction signal for a predetermined period, and the output signal of the area signal generating means. Based on the above, a video signal recording / reproducing apparatus comprising a switching means for switching the reproduction signal and the output of the delay means. 2. A video signal recording / reproducing apparatus for FM-modulating a video signal and time-division multiplexing and recording / reproducing a digital audio signal in the blanking period of the FM-modulated recording video signal. The delay time of the delay means for delaying is the predetermined horizontal scanning period in the recording signal, and the output of the delay signal delayed by the reproduction signal and the predetermined horizontal scanning period is switched based on the control signal indicating the area of the digital audio signal. The video signal recording / reproducing apparatus according to claim 1, wherein. 3. A video signal recording / reproducing apparatus for FM-modulating a video signal and time-division multiplexing and recording / reproducing a digital audio signal in the blanking period of the FM-modulated recording video signal. Area signal generating means for determining the area of the digital audio signal and generating a control signal indicating the area of the digital audio signal, FM signal generating means for generating a signal obtained by FM-modulating a signal of a predetermined frequency, and the area A video signal recording / reproducing apparatus comprising: a switching means for switching the reproduction signal and the output of the FM signal generating means based on the output signal of the signal generating means.