JPH04212595A - Video signal recording and/or reproducing device - Google Patents

Abstract

PURPOSE:To constitute the above device in such a manner that the brightness signal and color signals subjected to time base compression are subjected to the time base compression at the time of reproducing and an adequate reference point is set at the time of the time base expansion of the time base multiplexed and synthesized brightness signal and color signals at the time of recording the above-mentioned brightness signal and color signals together with color burst signals by time base multiplexing and synthesizing. CONSTITUTION:The burst synthesized signals obtd. by superposing the segmented time base compressed brightness signal obtd. by time base compression of the brightness signal Y at every one horizontal period, the segmented time base compressed color signals obtd. by time base compression of the color signals R-Y, B-Y at every one horizontal period and the color burst signal on the auxiliary signals which have the frequencies lower than the frequencies of these signals and have at least one piece of zero cross points within the period of the color burst signal are time base multiplexed and synthesized to successively formed the video signals for recording of respective horizontal periods and these signals are recorded on a recording medium 30A.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention compresses a luminance signal and a color signal forming a color video signal in a time axis, combines them in a time axis multiplexed manner, and records them on a recording medium. The present invention relates to a video signal recording and/or reproducing device that reproduces original luminance signals and color signals from a recording medium on which axis-multiplexed luminance signals and color signals are recorded.

0002

2. Description of the Related Art As one method for recording color video signals on a magnetic tape using a video tape recorder (VTR), a luminance signal and a chrominance signal forming the color video signal each have a predetermined ratio of time. Perform axis compression and time axis multiplexing of the time axis compressed luminance signal and color signal,
It has been proposed to supply a common recording magnetic head that forms recording tracks on the magnetic tape.

[0003] When recording a color video signal using such a technique of time-base compression multiplexing of luminance signals and color signals, for example, the luminance signal Y is subjected to time-base compression for each horizontal period. The segmented time-base compressed luminance signal Y' having information for one horizontal period is sequentially obtained, and each of the two color difference signals (R-Y) and (B-Y) forming the color signal is transmitted for that one horizontal period. A segmented time-axis compressed color difference signal (R-Y)' which is time-axis compressed every minute and has information for one horizontal period.
and (B-Y)' are obtained sequentially, and each segmented time-axis compressed luminance signal Y' and its corresponding segmented time-axis compressed color difference signal (R
-Y)' and (B-Y)' are time-axis multiplexed, and a horizontal synchronization signal and a color burst signal are added to create recording video signals for each horizontal period as shown in FIG. Formed sequentially. In the example shown in FIG. 8, following the horizontal blanking period HBL, the segmented time-axis compressed color difference signal (RY)' and the segmented time-axis compressed color difference signal (B-Y)'
, and the segmented time-axis compressed luminance signal Y' are sequentially arranged to form a recording video signal for one horizontal period, and the segmented time-axis compressed color difference signals (R-Y)' and (B-Y)' Each of these has a compression rate four times that of the segmented time-base compressed luminance signal Y'.

[0004] Furthermore, in the horizontal blanking period HBL,
As shown in the enlarged diagram in FIG. 8, the horizontal synchronization signal H
P and a color burst signal SB are arranged.

[0005] Recording of color video signals on magnetic tape is
Recording video signals for each horizontal period, including segmented time-axis compressed luminance signal Y' and segmented time-axis compressed color difference signals (RY)' and (B-Y)' as shown in FIG. In this case, the configuration of the recording magnetic head is simplified by making the recording magnetic head unit common for luminance signals and color signals, and the frequency bands of recording video signals are compared. This has the advantage of being narrower in scope.

Then, as shown in FIG. 8, a segmented time axis compressed luminance signal Y' and a segmented time axis compressed color difference signal (RY) are obtained.
A luminance signal Y from a magnetic tape on which recording video signals of each horizontal period including ' and (B-Y)' are sequentially recorded.
When the color difference signals (R-Y) and (B-Y) forming the color signals are reproduced, the reproducing magnetic head reads the segmented time-axis compressed luminance signal Y' and the segmented time-axis compressed color difference signal (Y') from the magnetic tape. The recording video signal of each horizontal period including R-Y)' and (B-Y)' is sequentially read out, and the segmented time axis in the recording video signal of each horizontal period obtained from the reproducing magnetic head is The compressed luminance signal Y' and the segmented time-axis compressed color difference signals (R-Y)' and (B-Y)' are each subjected to time-axis expansion and extracted, and the original luminance signal Y for one horizontal period and the original Color difference signals (RY) and (B-Y) for one horizontal period of
) is played.

At that time, the segmented time axis compressed luminance signal Y' and the segmented time axis compressed color difference signals (R-Y)' and (B-Y)'
A reference time point is set in the recording video signal of each horizontal period obtained from the reproducing magnetic head, and the time axis extension for each of the above is performed based on the reference time point. For example, as shown in FIG. 9, such a reference time point is set when a preset period T has elapsed from the leading edge of the horizontal synchronization signal HP in the recording video signal of each horizontal period obtained from the reproducing magnetic head. A gate pulse PG is formed having a leading edge at a point in time and is gated by the gate pulse PG;
This is done by setting the zero-crossing point Qz in the color burst signal SB placed following the horizontal synchronization signal HP as a reference time, and a reference time pulse PT having a leading edge at the reference time is formed, which is used for classification. It is used to represent the reference timing for the clock pulse for time axis expansion for each of the time axis compressed luminance signal Y' and the segmented time axis compressed color difference signals (RY)' and (BY)'.

[0008]

As described above, the segmented time axis compressed luminance signal Y' and segmented time axis compressed color difference signal (R-Y )' and (B-Y)', when a preset period T has elapsed from the leading edge of the horizontal synchronization signal HP in the recording video signal of each horizontal period. When the reference time pulse PT is formed by setting the time point of the zero crossing point Qz in the color burst signal SB gated by the gate pulse PG having a leading edge as the reference time point, as shown by the dashed line in FIG. If the horizontal synchronizing signal in the recording video signal for each horizontal period obtained from A gate that is delayed with respect to the time of the leading edge detected for HP, and accordingly has a leading edge at a time when a preset period T has elapsed from the leading edge of the horizontal synchronization signal HP'. The pulse also lags behind the gate pulse PG, which has its leading edge at the time when a preset period T has elapsed from the leading edge of the proper horizontal synchronizing signal HP, as represented by the gate pulse PG' indicated by a dashed line. . As a result, the zero-crossing point Qz' in the color burst signal SB which is gated by the gate pulse PG' and whose point in time is taken as the reference point is compared to the zero-crossing point Qz in the proper color burst signal SB which is gated by the gate pulse PG. For example, the color burst signal SB will be delayed by one period τ, and the reference time pulse P obtained at that time will be delayed by one period τ of the color burst signal SB.
T' is delayed by a period corresponding to τ compared to the appropriate reference time pulse PT.

[0009] Then, a segmented time-axis compressed luminance signal Y' and a segmented time-axis compressed color difference signal (R-Y)' are generated by a clock pulse based on a reference time pulse PT' that is delayed compared to the appropriate reference time pulse PT. and (B-Y)', the luminance signal Y or the color difference signals (R-Y) and (B-Y) are not properly reproduced, and the reproduced image based on them is This results in inconveniences such as "misalignment".

In view of the above, the present invention applies time axis compression to each of the luminance signal and chrominance signal forming a color video signal at a predetermined ratio, and compresses the time axis compressed luminance signal and chrominance signal in time. Axis multiplexing is performed and recorded on a recording medium, and each of the luminance signals and color signals read out from the recording medium, time-axis compressed, and time-axis multiplexing composited is extracted by time-axis expansion, and the original luminance is restored. When reproducing signals and color signals, when time-axis compressed luminance signals and color signals are time-axis multiplexed and recorded on a recording medium, the time-axis compressed and time-axis multiplexed luminance signals and A video signal recording device that can always set an appropriate reference time point when each color signal is time-axis expanded, and furthermore, a video signal recording device that can perform time-axis compression and time-axis multiplexing of each color signal read from a recording medium. It is an object of the present invention to provide a video signal reproducing device in which an appropriate reference time point is always set when time-axis expanding each of a combined luminance signal and color signal.

[0011]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the video signal recording device according to the present invention compresses the time axis of a luminance signal forming a video signal for each horizontal period and divides the luminance signal into a segmented time axis. A first time-base compression processing unit that sequentially obtains compressed luminance signals, and a first time-axis compression processing unit that sequentially obtains compressed luminance signals and a color signal that forms a video signal together with the luminance signals.
a second time-base compression processing unit that performs time-base compression for each horizontal period to sequentially obtain segmented time-base compressed color signals, a signal supply unit that supplies a burst composite signal, and a signal obtained from the first time-base compression processing unit. The segmented time-base compressed luminance signal corresponding to the second
A recording signal that sequentially forms a recording video signal for each horizontal period by time-axis multiplexing the segmented time-axis compressed color signal obtained from the time-axis compression processing unit and the burst composite signal supplied from the signal supply unit. The recording head unit records the recording video signal obtained from the recording signal forming unit onto a recording medium, and the burst composite signal supplied from the signal supply unit is provided within each horizontal period of the video signal. the color burst signal to be distributed has a lower frequency;
It is configured to be obtained by being superimposed on an auxiliary signal that has at least one zero crossing point within the period of the color burst signal.

[0012] Furthermore, the video signal reproducing device according to the present invention includes:
A segmented time-base compressed luminance signal obtained by time-base compressing the luminance signal forming the video signal every horizontal period, and a color signal forming the video signal together with the luminance signal compressing the time axis every horizontal period. A segmented time-base compressed color signal obtained by compression and corresponding to the segmented time-base compressed luminance signal, and a color burst signal to be arranged within each horizontal period,
A burst composite signal obtained by being superimposed on an auxiliary signal having a lower frequency and having at least one zero crossing point within the period of the color burst signal is time-axis multiplexed and combined to form each horizontal period component. A playback head section reads out a recording video signal from a recording medium on which the recorded video signal is recorded, and a playback burst signal and a playback auxiliary signal are obtained from the recording video signal read out by the playback head section. The first signal reproduction processing section, the reference time point setting section, and the respective section time-axis compressed luminance signal and each section time-axis compressed color signal in the recording video signal read out by the playback head section are set at the reference point in time. a second signal reproduction processing section that expands the time axis based on the reference time set by the setting section, extracts it, and reproduces the luminance signal and color signal forming the video signal, the reference time setting section; The reference time point is set based on the zero-crossing point in the reproduction auxiliary signal obtained from the first signal reproduction processing section and the zero-crossing point in the reproduction burst signal obtained from the first signal reproduction processing section. be done.

[0013]

[Operation] In the video signal recording apparatus according to the present invention configured as described above, a recording signal obtained by time-axis multiplexing the time-axis compressed luminance signal and color signal together with the synchronization signal and the color burst signal. When a video signal is recorded on a recording medium, the time axis is compressed during playback, and the luminance signal and chrominance signal, which are time axis multiplexed and combined, are each expanded in the time axis. This is done on the assumption that it will always be set appropriately.

Further, in the video signal reproducing apparatus according to the present invention, the recording video signal obtained by time-axis multiplexing the time-axis compressed luminance signal and color signal together with the synchronization signal and the color burst signal is recorded. When each of the luminance signals and chrominance signals read from the recorded recording medium, which have been time-axis compressed and time-axis multiplexed and synthesized, is time-axis expanded, the reference time point for specifying the period of each signal is always set. If set appropriately, the luminance signal and color signal forming the video signal will be reproduced correctly.

[0015]

[Embodiment] FIG. 1 shows an example of a video signal recording device according to the present invention. In this example, the video signal is a luminance signal Y
and is separated into two color difference signals (RY) and (BY) and supplied.

In FIG. 1, a luminance signal Y, a color difference signal (RY), and a color difference signal (B-Y) are supplied to signal input terminals 11, 12, and 13, respectively.

The luminance signal Y from the signal input terminal 11 is given a predetermined direct current level (DC level) in a clamp circuit 14, and then converted into a digital luminance signal DY in an analog/digital (A/D) conversion circuit 15. and supplied to the memory 16. Further, the color difference signal (R-Y) from the signal input terminal 12 and the color difference signal (B-Y) from the signal input terminal 13 are sent to clamp circuits 17 and 18, respectively.
, a predetermined DC level corresponding to the DC level given to the luminance signal Y is given by the clamp circuit 14, and then converted into digital color difference signals DR and DB in the A/D conversion circuits 19 and 20, and then sent to the memories 21 and 22.
supplied to

In the memory 16, the digital luminance signal DY is divided and written for each horizontal period according to the write clock signal Cw having a predetermined frequency sent from the timing signal generator 23, and
The written digital luminance signal DY for one horizontal period is read out according to the read clock signal Cr1 having a higher frequency than the write clock signal Cw, which is sent from the timing signal generator 23, and the written and The read operation is performed sequentially for each horizontal period of the digital luminance signal DY. As a result, each horizontal period of the digital luminance signal DY is stored in the memory 16 as a digital signal obtained by compressing the time axis at a compression ratio corresponding to the ratio of the frequency of the write clock signal Cw to the frequency of the read clock signal Cr1. The segmented time-base compressed luminance signal DY' is sequentially sent out and supplied to the selection contact 24a of the switch 24.

In addition, in the memory 21, the digital color difference signal DR is divided and written for each horizontal period according to the write clock signal Cw from the timing signal generating section 23, and the digital color difference signal DR is divided and written for each horizontal period. The digital color difference signal DR of 20 minutes is read out according to the read clock signal Cr2 having a higher frequency than the write clock signal Cw, which is sent from the timing signal generator 23, and the write and read operations are performed by the digital color difference signal DR. This is performed sequentially for each horizontal period of DR. Thereby, each horizontal period of the digital color difference signal DR is stored in the memory 21 as a digital signal obtained by compressing the time axis at a compression ratio corresponding to the frequency ratio of the write clock signal Cw to the frequency of the read clock signal Cr2. The segmented time axis compressed color difference signal DR' is sequentially sent out to the switch 2.
4 selection contact 24b. The frequency of the read clock signal Cr2 is, for example, the read clock signal Cr1.
Therefore, the time axis compression ratio of the digital segmented time axis compressed color difference signal DR' is set to be four times the time axis compression ratio of the digital segmented time axis compressed luminance signal DY'.

Further, in the memory 22, the digital color difference signal DB is divided and written in each horizontal period according to the write clock signal Cw from the timing signal generating section 23, and the digital color difference signal DB is written in each horizontal period. The digital color difference signal DB of minutes is read out according to the read clock signal Cr3 having a higher frequency than the write clock signal Cw, which is sent from the timing signal generator 23, and the writing and reading operations are performed using the digital color difference signal. This is performed sequentially for each horizontal period of DB. As a result, each horizontal period of the digital color difference signal DB is stored in the memory 22 as a digital signal obtained by compressing the time axis at a compression ratio according to the ratio of the frequency of the write clock signal Cw to the frequency of the read clock signal Cr3. The segmented time-base compressed color difference signals DB' are sequentially sent out and supplied to the selection contact 24c of the switch 24. The frequency of the read clock signal Cr3 is set to be equal to the frequency of the read clock signal Cr2, and is selected to be, for example, four times the frequency of the read clock signal Cr1,
Therefore, the time axis compression ratio of the digitally divided time axis compressed color difference signal DB' is also the same as that of the digitally divided time axis compressed luminance signal DY.
It is assumed to be four times the time axis compression ratio of '.

A readout clock signal Cr1, which is sent from the timing signal generator 23 to read out the digital luminance signal Y and the digital color difference signals DR and DB for one horizontal period written in the memories 16, 21 and 22, respectively;
Cr2 and Cr3 have different transmission periods, with the reading clock signal Cr2 being sent out in the earliest period, followed by the reading clock signal Cr3 and the reading clock signal Cr1 being sent out in sequence. Therefore, the digital segmented time-base compressed luminance signal DY' obtained from the memory 16,
and correspondingly digital segmented time-base compressed color difference signals DR' and DB obtained from the memories 21 and 22, respectively.
', a digital segmented time-base compressed color difference signal DR' is obtained first, followed by a digital segmented time-base compressed color difference signal DB' and a digital segmented time-base compressed luminance signal D.
It is assumed that Y' can be obtained sequentially.

The timing signal generator 23 outputs a switch control signal W1 that changes in accordance with the output of the reading clock signals Cr1, Cr2, and Cr3, and supplies it to the switch 24, which outputs the switch control signal W1. The movable contact 24d of the switch 24 is connected to the selection contact 24a during the period when the reading clock signal Cr1 is sent out, is connected to the selection contact 24b during the period when the reading clock signal Cr2 is sent out, and is connected to the selection contact 24b during the period when the reading clock signal Cr2 is sent out. Clock signal Cr3
It is assumed that the selection contact 24c is connected to the selection contact 24c during the period in which the signal is sent. Thereby, the movable contact 24 in the switch 24
d, the digital segmented time-base compressed luminance signal DY' obtained from the memory 16 and the corresponding memory 2
The digital segmented time axis compressed color difference signals DR' and DB' obtained from signals 1 and 22, respectively, are a digital segmented time axis compressed color difference signal DR', a digital segmented time axis compressed color difference signal DB', and a digital segmented time axis compressed luminance signal DY'. are derived sequentially in the order of That is, the digital segmented time-base compressed luminance signal DY' and the digital segmented time-base compressed color difference signals DR' and DB' are time-axis multiplexed and synthesized, and the digital segmented time-base compressed luminance signal DY' is obtained by time-axis multiplexed synthesis. and digital segmented time-base compressed color difference signals DR' and DB' are supplied to the selection contact 25a of the switch 25.

Further, from the timing signal generation section 23,
The read clock signal Cr4 is also the read clock signal Cr.
2, and is supplied to a read-only memory (ROM) 26. The ROM 26 stores a digital horizontal signal obtained by digitizing a horizontal synchronizing signal HP and a burst composite signal SS+SB obtained by superimposing a color burst signal SB on a subsequent sine wave signal SS, as shown in FIG. A synchronizing signal DH and a digital burst composite signal DS+DB are stored. The sine wave signal SS is used as an auxiliary signal for the color burst signal SB, and is selected to have a lower frequency than the color burst signal SB and to have at least one zero crossing point within the period of the color burst signal SB. . Then, the digital horizontal synchronizing signal DH and the digital burst composite signal DS+DB are read out from the ROM 26 in accordance with the reading clock signal Cr4, and these signals are sent to the switch 2.
5 selection contact 25b.

Furthermore, the timing signal generator 23 outputs a switch control signal W2 that changes in synchronization with the output of the reading clock signal Cr4, and is supplied to the switch 25. The movable contact 25c is connected to the selection contact 25a during a period when the reading clock signal Cr4 is not sent out, and is connected to the selection contact 25b during a period when the reading clock signal Cr4 is sent out. As a result, from the movable contact 25c of the switch 25, the digital segmented time-base compressed color difference signal DR', the digital segmented time-base compressed color difference signal DB' obtained from the movable contact 24d of the switch 24,
And, prior to the digital segmented time-base compressed luminance signal DY', a digital horizontal synchronizing signal DH and a digital burst composite signal DS+DB are derived from the ROM 26,
Subsequently, the digital segmented time-base compressed color difference signal DR', the digital segmented time-base compressed color difference signal DB', and the digital segmented time-base compressed luminance signal DY' are sequentially derived from the switch 24. That is, switch 2
A digital horizontal synchronizing signal DH, a digital burst composite signal DS+DB, a digital segmented time-base compressed luminance signal DY', and a digital segmented time-base compressed color difference signal DR' and DB' are time-axis multiplexed and synthesized at the movable contact 25c at 5. As a result, the digital recording video signal DM for one horizontal period is formed.Therefore, from the movable contact 25c of the switch 25, the digital recording video signal DM for one horizontal period is sequentially derived. become.

The digital recording video signal DM for one horizontal period obtained from the movable contact 25c of the switch 25 is converted into an analog signal in a digital/analog (D/A) conversion circuit 27, and is converted into a horizontal synchronizing signal HP, a burst composite signal SS+SB, The segmented time-axis compressed luminance signal Y' and the segmented time-axis compressed color difference signals (R-Y)' and (B-Y)' are time-axis multiplexed to form a recording video signal SM for one horizontal period. Ru. Such recording video signal SM is shown in FIG.
As shown in FIG. 8, following the horizontal synchronizing signal HP and the burst composite signal SS+SB in which the color burst signal SB is superimposed on the sine wave signal SS, the recording video signal shown in FIG. Similarly, it is assumed that the segmented time-axis compressed color difference signal (RY)', the segmented time-axis compressed color difference signal (B-Y)', and the segmented time-axis compressed luminance signal Y' are arranged in sequence.

The recording video signal SM for one horizontal period sequentially obtained from the D/A conversion circuit 27 is subjected to frequency modulation (
In the FM circuit 28, a predetermined carrier wave signal is converted into a modulation signal by performing FM, and an FM video signal FSM for recording is obtained from the FM circuit 28. Then, the recording FM video signal FS
M is supplied to a rotating magnetic head 30 constituting a recording head section through a recording amplifier circuit 29, and is recorded on a magnetic tape 30A by the rotating magnetic head 30.

FIG. 4 shows an example of a video signal reproducing device according to the present invention. In this example, the video signal recording device shown in FIG. , luminance signal Y and color difference signal (
It is supposed to reproduce R-Y) and (B-Y),
Further, the rotating magnetic head 30 in the video signal recording apparatus shown in FIG. 1 is also used as the magnetic head constituting the reproduction head section.

In FIG. 4, the recording FM video signal FSM read from the magnetic tape 30A by the rotating magnetic head 30 is frequency demodulated (
FDM) circuit 32. In the FDM circuit 32, the recording FM video signal FSM is demodulated to sequentially obtain recording video signals SM for one horizontal period, and these are set to have a predetermined DC level in the clamp circuit 33.

The recording video signal SM obtained from the clamp circuit 33 is sent to an A/D conversion circuit 34 and a filter forming section 35.
, a synchronization separation circuit 36, and a clock recovery circuit 37, respectively.

The filter forming section 35 receives the recording video signal S.
A pair of delay elements (D.L.) 38 and 39 are connected in series, each having a delay time of 1/2 of the period τ of the color burst signal SB, that is, τ/2, to which D.M is supplied. L.
an amplifier circuit 40 with a gain of 2 to which the output of 38 is supplied;
, D. from the output of the amplifier circuit 40. L. 38 and D.38. L. 39, and a subtraction circuit 41 that subtracts the output of D.
．． L. From the input to D.38. L. The circuit includes a subtraction circuit 42 that subtracts the output of 39. And D. L.
38 and 39, an amplifier circuit 40 and a subtraction circuit 41, a relatively narrow passing frequency centered around the frequency fb of the color burst signal SB, as shown in FIG. 6 (horizontal axis: frequency f, vertical axis: level L). A bandpass filter is formed having a D. L. 7 (horizontal axis: frequency f, vertical axis: level L).
), a comb-shaped filter is formed in which non-passing frequencies are the frequency fb of the color burst signal SB and frequencies that are integral multiples thereof.

The filter forming section 35 is supplied with a horizontal synchronizing signal HP and a sine wave signal S as shown in FIG. 5A.
The subtraction circuit 4
2, as shown in FIG. 5B, the recording video signal S
A horizontal synchronizing signal HP and a sine wave signal SS, which are low frequency components of M, are obtained with the DC level set to zero, and are supplied to the comparison input terminal of a window comparator (W.COMP) 43, and from the subtraction circuit 41. As shown in FIG. 5C, the color burst signal SB in the recording video signal SM is obtained with the DC level set to zero, and is supplied to the comparison input terminal of the comparator 44.

A pair of reference input terminals of the window comparator 43 are supplied with a relatively small negative reference voltage -Vr and a positive reference voltage +Vr, respectively, so that the window comparator 43 outputs the voltage shown in FIG. As shown in D, the high level is determined depending on the portion of the horizontal synchronizing signal HP and sine wave signal SS supplied to the comparison input terminal that takes a level between the negative reference voltage -Vr and the positive reference voltage +Vr. A comparison output signal SW is obtained, and this comparison output signal SW has a high level portion SZ corresponding to the zero crossing point of the sine wave signal SS and a portion in the vicinity thereof. Further, the ground potential is supplied to the reference input terminal of the comparator 44, and the color burst signal SB is supplied from the comparator 44 to the comparison input terminal as shown in E of FIG.
A comparison output signal ST that takes a high level is obtained in accordance with a portion that takes a positive level. The comparison output signal SW from the window comparator 43 and the comparison output signal ST from the comparator 44 are supplied to an AND circuit 45.

In the synchronization separation circuit 36 to which the recording video signal SM is supplied, the synchronization signal in the recording video signal SM is separated, and based on the separated horizontal synchronization signal HP, the synchronization signal shown in FIG. Horizontal synchronization signal HP
A gate pulse PG having a leading edge and taking a relatively wide positive level is formed when a preset period T has elapsed from the leading edge of the gate pulse PG. Then, the gate pulse PG formed in the synchronization separation circuit 36 is supplied to the AND circuit 45. In the AND circuit 45, the comparison output signal SW from the window comparator 43, the comparison output signal SW from the comparator 4
4 and the gate pulse PG from the synchronization separation circuit 36.
AND" is performed to obtain an output, and as a result, the AND circuit 45 outputs the color burst signal SB corresponding to the zero-crossing point of the sine wave signal SS or a portion in the vicinity thereof, as shown in G of FIG. Zero cross point (Figure 5
A pulse signal having a leading edge at a time point corresponding to Qz) at C is obtained and is taken as the reference time pulse PT.

The reference time pulse P obtained in this way
T is an "AND" of the positive level portion of the comparison output signal SW from the window comparator 43, the comparison output signal ST from the comparator 44, and the gate pulse PG from the synchronization separation circuit 36 in the AND circuit 45. By being taken and obtained, parable;
Horizontal synchronization signal HP separated in synchronization separation circuit 36
is assumed to have become dull, and the time point at which it is detected as its leading edge is somewhat delayed from the time point at which the leading edge is detected for the proper horizontal synchronization signal HP. Even if the width of the fluctuation is about 1/2 or less of the width of the gate pulse PG, the time point will not be changed, and therefore, a constant appropriate reference time point will always be maintained. It becomes something that is expressed. The reference time pulse PT obtained from the AND circuit 45 is then supplied to the timing signal generator 46.

The horizontal synchronization signal HP separated by the synchronization separation circuit 36 is also supplied to a timing signal generation section 46 and a clock regeneration circuit 37 to which the recording video signal SM is supplied. The clock reproducing circuit 37 uses, for example, a phase locked loop (PLL) to generate a clock signal CL synchronized with the clock timing in the recording video signal SM and the horizontal synchronization signal HP, and transmits the clock signal CL to the timing signal generator 46. supply to. Based on the clock signal CL from the clock reproducing circuit 37, the timing signal generator 46 generates write clock signals having the same frequencies as the read clock signals Cr1, Cr2, and Cr3 used in the video signal recording apparatus shown in FIG. Clock signal Cw1,C
w2 and Cw3, a read clock signal Cr having the same frequency as the write clock signal Cw used in the video signal recording device shown in FIG. The segmented time axis compressed color difference signal (R-
Y)', a period corresponding to the period of the segmented time-axis compressed color difference signal (B-Y)', and a period corresponding to the period of the segmented time-axis compressed luminance signal Y', respectively. The writing clock signal Cw2 is sent to the memory 48, the writing clock signal Cw3 is sent to the memory 49, and the writing clock signal Cw1 is sent to the memory 47, and each recording video signal SM is In the obtained horizontal period, the read clock signal Cr is sent to each of the memories 48, 49, and 47.

At this time, the memory 48 of the write clock signal Cw2 is performed in the timing signal generator 46.
The period during which the write clock signal Cw3 should be sent to the memory 49, and the period during which the write clock signal Cw1 should be sent to the memory 47 are set by the synchronization separation circuit. 36 and the reference time pulse PT obtained from the AND circuit 45, each period corresponds to each recording video signal SM.
The period of the segmented time-base compressed color difference signal (RY)' in ,
This will appropriately correspond to the period of the segmented time-axis compressed color difference signal (B-Y)' and the period of the segmented time-axis compressed luminance signal Y'.

On the other hand, in the A/D conversion circuit 34 to which each recording video signal SM obtained from the clamp circuit 33 is supplied, the recording video signal SM is digitized into a segmented time-base compressed color difference signal (R- A digital segmented time axis compressed color difference signal DR' based on the segmented time axis compressed color difference signal (B-Y)', a digital segmented time axis compressed color difference signal DB' based on the segmented time axis compressed color difference signal (B-Y)', and a segmented time axis compressed luminance signal Y'. A digital recording video signal DM containing the digital segmented time-base compressed luminance signal DY' based on the above-mentioned data is formed and supplied to each of the memories 47, 48 and 49. In the memory 47, the digital recording video signal DM is generated in accordance with the writing clock signal Cw1 sent from the timing signal generating unit 46 in a period corresponding to the period of the segmented time axis compressed luminance signal Y' in each recording video signal SM. The digital segmented time-base compressed luminance signal DY' is written, and the written digital segmented time-base compressed luminance signal DY' is read out over one horizontal period in accordance with the reading clock signal Cr from the timing signal generator 46. The digital segmented time axis compressed luminance signal DY' is output from the memory 47.
A digital luminance signal DY obtained by time-axis expansion is sequentially derived and supplied to the D/A conversion circuit 50.

In addition, in the memory 48, a write clock signal is sent out from the timing signal generator 46 during a period corresponding to the period of the segmented time axis compressed color difference signal (RY)' in each recording video signal SM. According to Cw2, the digital segmented time axis compressed color difference signal DR' in the digital recording video signal DM is written, and the written digital segmented time axis compressed color difference signal DR' is written in accordance with the read clock signal Cr from the timing signal generator 46. A digital color difference signal DR read out over one horizontal period and obtained by time-axis expanding the digital segmented time-base compressed color difference signal DR' is sequentially derived from the memory 48 and supplied to the D/A conversion circuit 51. Ru. Furthermore, in the memory 49, the segmented time axis compressed color difference signal (B-
According to the write clock signal Cw3 sent out during the period corresponding to the period Y)', the digital recording video signal DM is
The digital segmented time-base compressed color difference signal DB' is written, and the written digital segmented time-base compressed color difference signal DB' is read out over one horizontal period in accordance with the read clock signal Cr from the timing signal generator 46. Then, digital color difference signals DB obtained by time-axis expanding the digital segmented time-base compressed color difference signal DB' are sequentially derived from the memory 49 and supplied to the D/A conversion circuit 52.

In the D/A conversion circuit 50, the memory 4
The digital luminance signal DY sequentially obtained from 7 is continuously converted into analog to reproduce the luminance signal Y, which is output to the output terminal 53. Further, in the D/A conversion circuit 51, the digital color difference signal DR sequentially obtained from the memory 48 is continuously converted into an analog signal to reproduce a color difference signal (RY), which is outputted to the output terminal 54. moreover,
In the D/A conversion circuit 52, the digital color difference signal DB sequentially obtained from the memory 49 is continuously converted into analog to reproduce the color difference signal (B-Y), which is output to the output terminal 5.
5. In this way, the luminance signal Y and color difference signals (RY) and (B-Y) forming the video signal are reproduced from the magnetic tape 30A.

In the recording video signal recorded on the magnetic tape 30A by the above-mentioned example of the video signal recording device, and in the recording video signal read from the magnetic tape 30A by the above-mentioned example of the video signal reproducing device, color burst The auxiliary signal on which the signal SB is superimposed is the sine wave signal SS, but instead of the sine wave signal SS, the auxiliary signal has a lower frequency than the color burst signal SB,
A sawtooth wave signal, a triangular wave signal, or the like having at least one zero-crossing point within the period of the color burst signal SB may be used.

[0041]

As is clear from the above description, according to the video signal recording device of the present invention, time-axis compressed luminance signals and chrominance signals are obtained by time-axis multiplexing and combining together with synchronization signals and color burst signals. During playback of a recording video signal recorded on a recording medium, the time axis is compressed and the time axis is expanded for each of the luminance signal and chrominance signal that are time axis multiplexed. This can be done on the assumption that the reference time point for identification will always be properly set.

Further, according to the video signal reproducing apparatus of the present invention, a recording video signal obtained by time-axis multiplexing the time-axis compressed luminance signal and color signal together with the synchronization signal and the color burst signal is recorded. When time-axis expanding each of the luminance signals and color signals read from a recording medium that has been time-axis compressed and time-axis multiplexed, the reference time point for specifying the period of each signal is always properly set. This makes it possible to correctly reproduce the luminance signal and color signal forming the video signal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a video signal recording device according to the present invention.

FIG. 2 is a waveform diagram showing a burst composite signal in the example of the video signal recording device shown in FIG. 1;

FIG. 3 is a waveform diagram showing a portion of a recorded video signal in the example of the video signal recording device shown in FIG. 1;

FIG. 4 is a block configuration diagram showing an example of a video signal reproducing device according to the present invention.

FIG. 5 is a waveform diagram showing various signals in the example of the video signal reproducing device shown in FIG. 4;

FIG. 6 is a characteristic diagram showing filter characteristics in a filter component in the example of the video signal reproducing device shown in FIG. 4;

7 is a characteristic diagram showing filter characteristics in a filter component in the example of the video signal reproducing device shown in FIG. 4; FIG.

FIG. 8 is a waveform diagram showing a recording video signal formed by time-axis multiplexing and combining time-axis compressed luminance signals and color signals together with synchronization signals and color burst signals.

9 is a time chart used to explain setting of a reference time point for the recording video signal shown in FIG. 8; FIG.

[Explanation of symbols]

14 Clamp circuit 16 Memory 17 Clamp circuit 18 Clamp circuit 21 Memory 22 Memory 23 Timing signal generation section 26 Read-only memory 28 Frequency modulation circuit 30 Rotating magnetic head 32 Frequency demodulation circuit 33 Clamp circuit 35 Filter forming part 36 Synchronous separation circuit 37 Clock regeneration circuit 43 Window comparator 44 Comparator 45 AND circuit 46 Timing signal generation section 47 Memory 48 Memory 49 Memory

Claims (2)

[Claims] 1. A first time-base compression processing unit that sequentially compresses the time-base of a luminance signal forming a video signal for each horizontal period to sequentially obtain segmented time-base compressed luminance signals; a second time-base compression processing unit which sequentially obtains segmented time-base compressed color signals by time-base compressing the color signal formed together with the signal for each horizontal period; a signal supply unit for supplying a burst composite signal obtained by superimposing the color burst signal to be obtained by superimposing it on an auxiliary signal having a lower frequency than the color burst signal and having at least one zero crossing point within the period of the color burst signal; and a segmented time axis compressed luminance signal obtained from the first time axis compression processing section, and a segmented time axis compressed color signal obtained from the second time axis compression processing section corresponding to the segmented time axis compressed luminance signal. , and a recording signal forming unit that time-axis multiplexes the burst composite signals supplied from the signal supply unit to sequentially form a recording video signal for each horizontal period, and a recording signal forming unit that sequentially forms a recording video signal for each horizontal period, and a recording signal obtained from the recording signal forming unit. A video signal recording device comprising: a recording head section for recording a video signal on a recording medium. 2. A segmented time-base compressed luminance signal obtained by time-base compressing the luminance signal forming the video signal for each horizontal period, one of which is a color signal forming the video signal together with the luminance signal. Obtained by compressing the time axis for each horizontal period,
The segmented time-base compressed color signal corresponding to the segmented time-base compressed luminance signal and the color burst signal to be arranged within each horizontal period have a lower frequency than the color burst signal, and the color A recording video signal is created in which a burst composite signal obtained by being superimposed on an auxiliary signal that has at least one zero-crossing point within the period of the burst signal is time-axis multiplexed to form each horizontal period component. a playback head section that reads out the recording video signal from the recorded recording medium; and a first signal playback processing section that obtains a playback burst signal and a playback auxiliary signal from the recording video signal read out by the playback head section. and a reference time point setting unit that sets a reference time point based on the zero-crossing point in the reproduction auxiliary signal obtained from the first signal reproduction processing unit and the zero-crossing point in the reproduction burst signal obtained from the first signal reproduction processing unit. and each of the segmented time-axis compressed luminance signal and each segmented time-axis compressed color signal in the recording video signal read out by the playback head unit, with reference to the reference time set by the reference time setting unit. a second signal reproduction processing section that expands the time axis and extracts a luminance signal and a color signal forming a video signal under such conditions.