JPS59188290A - Recording and reproducing device for video signal - Google Patents

Abstract

PURPOSE:To compensate a dropout without losing the mutual relation between video signals by performing dropout compensation as to a signal part corresponding to a dropout section of a component video signal. CONSTITUTION:A VTR51 for reproduction is provided with dropout detecting circuits 72 and 80 and a dropout compensating circuit for the reproduction of a dubbing tape 34 with the dropout section. When there is a dropout at some part of a luminance signal S33, the detecting circuit 72 supplies its detection signal S39 to the compensating circuit in a component signal reproducing circuit 55. Further, the detecting circuit 80 detects a dropout in a color difference signal S31 and supplies the detection signal to the compensating circuit. The compensating circuit. The compensating circuit performs dropout compensation using the dropout signals as to all parts corresponding to the dropout section plural component video signals have close relation.

Description

[Detailed Description of the Invention] [Field of Sedentary Work] The present invention relates to a video signal recording and reproducing device, and is particularly suitable for application to a case where a plurality of component video signals are time-axis compressed, multiplexed, and recorded. It is.

[Background technology and its problems]

As this ideal video signal recording apparatus, one having the configuration shown in FIG. 1 has been proposed. That is, in a recording video tape recorder (VTR) NC, a plurality of component video signals constituting composite input video number i, that is, a luminance signal Y and R-Y and B-Y color difference signals are applied to the recording circuit 2, and a synchronizing signal is applied to each component video signal. By inserting 5YNC, a recording scissor intensity signal Y and a recording pressure multiplexed color difference signal (R'-Y) and CB''Y) which are synchronized with each other are created, respectively. 4, one horizontal constant scan is recorded on the luminance signal track and the chrominance signal track of the tape 5.

Here, the compressed multiplication factor (R-Y')・(B-Y)
In the recording circuit 2, the unit number R of one horizontal opening period is
-Y and B-Y are compressed on the 7 time axes and sequentially time-series multiplexed.

The luminance signal Y and the multiplexed color difference signals (R-Y) and (B-Y) as a plurality of component video signals recorded as components on the tape 5 in this manner are transmitted to the VT for reproduction.
It is supplied to the reproduction circuit 9 via the reproduction heads 7 and 8 of R6, and reproduces the luminance signal Y and also reproduces the multiplexed color difference signal (R
-Y) and (B-Y) to each color difference signal R, -Y and B-Y
are separated, the time axis is expanded twice, and the signal is synchronized and encoded into a color signal C. The reproduction circuit 9 is given a reference synchronization signal REFSYNC as an external synchronization signal, and this reference synchronization signal 11'''5YNCKm degree double Y and color signal C
are synchronized and fed to the synthesis circuit 10 together with the luminance signal Y and color signal C to produce a composite output video signal S1.
Synthesize.

The video signal recording and reproducing apparatus having such a configuration is R-Y and B-
Since the Y color difference signal is multiplexed and recorded, there is an advantage that the vertical coverage of the color can be prevented from being halved compared to the case where the Y color difference signal is recorded in the forest sequential manner.

By the way, in the video signal recording and reproducing apparatus having the configuration shown in FIG. In general, it is considered to compensate for dropouts by extracting the pre-IH playback signal portion corresponding to the dropout section from the playback signal and inserting it into the dropout district 1 city. It will be done. However, if this is done, when a dropout occurs in a part of the compressed component a, the dropout compensation is performed only for the component signal and the signal part before IH is inserted, which is an inconvenience. I'm worried.

Incidentally, since each of the plurality of compressed and multiplied component video signals is a video signal component of one horizontal opening interval, each component video signal at each point in one horizontal interval has a proportional relation to each other. Therefore, if the signal portion before IH is inserted for only a part of the signal components, this interrelationship cannot be maintained, resulting in deterioration of image quality. In particular, as in the case of Figure 1, inserting the pre-IH signal part for one of the R-Y and B-Y color difference signals results in a drop in the color that could have been obtained if dropout did not occur. Due to the out-compensation, a color shift will occur in that signal portion.

[Purpose of the invention]

This invention was made in consideration of the above points, and when a dropout occurs in a part of each reproduced issue, the dropout correction is performed so as not to destroy the relationship between multiple component signals. We are trying to make it possible.

[Summary of the invention]

In order to achieve this object, in the present invention, when a dropout occurs in at least a portion of a plurality of reproduced component video signals, dropout compensation is performed for the portion corresponding to the cloud section.

〔Example〕

An embodiment of the present invention will be described below in detail with reference to the drawings. A video signal recording and reproducing apparatus includes luminance signals Y and R as component video signals constituting a composite video signal.
-Y and B-Y color difference signals are separated and recorded as components, respectively, as shown in FIG. 2 and G3).

For example, the component signal portion, that is, the luminance signal Y, generated in the camera section 15, and the synchronization (g@5YNC).

The color difference numbers R-Y and B-Y are given to the recording VTR unit 1G, and the synchronization signal circuit 17 inputs the input synchronization signal S Y
A clock signal 811 synchronized with the NC is generated and applied to the time axis compression multiplexing circuit 18. Time axis compression multiplexing circuit 18
is each water synchronization section H of the input luminance signal Y (Fig. 3 (4))
The input color differences (No.
In this way, as shown in FIG. 3(C), a multiplexed color difference signal SL2 is obtained by temporally dividing the compressed two color difference signals RY and BY.

This multiplexed color difference signal 812 is supplied with a synchronization signal 813 which is applied from the interpolation signal circuit 17 in the synchronization signal interpolation circuit 19.
is added, and the added multiplexed color difference signal S14 is frequency-modulated in a frequency demodulation circuit and component-recorded on the color signal track of the first tape B via the recording amplifier circuit 21 and the recording head 22.

On the other hand, the input luminance signal Y is added with a synchronization signal S13 in the synchronization addition circuit, and the added luminance signal 8
15 is frequency modulated by the frequency modulation circuit 5, and the recording amplifier circuit performs component recording on the luminance signal track of the first tape b via the recording head.

In practice, the signal formats shown in FIG. 4 (2) and CB) can be applied as the luminance signal S15 and multiplexed color difference signal S14 to be recorded as components. The distribution brightness 4m No. 815 receives an input synchronizing signal 5YNC in its 1 horizontal opening period H.
At the falling time t0 of the horizontal synchronizing signal of
A synchronizing pulse signal P1 that rises at 2 is inserted. On the other hand, the recording multiplicity difference signal S14 has the time t2.
A Y/C timing pulse signal P2 that falls at a time point t2 and rises at a time point t3 after a predetermined time (for example, 2.65 Cμs) has elapsed from this time point t2 is inserted, and the horizontal foothold section of the Y/C timing pulse signal P2 is inserted. TH started,
This traveling section ends at the trailing edge time t3 of the next Y/C timing pulse signal P2.

Thus, during reproduction, the luminance (sync pulse signal P of No. B S15
Synchronization with an external synchronization signal can be achieved by the leading edge of the Y/C timing pulse signal P2 of the multiplexed color difference signal S14, and the leading edge of the Y/C timing pulse signal P2 of the multiplexed color difference signal S14 is aligned with the trailing edge of the pulse P1 of the luminance signal 815. This makes it possible to synchronize the reproduced luminance signal and the reproduced luminance signal, and furthermore, the trailing edge of the Y/C timing pulse signal P2 represents the compression start bright point, and from the trailing edge of the pulse signal P2, ΣHO ) is designed to represent that there is a boundary between the compressed R-Y and B-Y color difference signals at time t4.

In this way, the first tape B, on which the input video signal coming from the camera unit 15 is recorded as a component, is applied to the reproducing VTR 32 of the dubbing device 31, and the recorded video signal is applied to the recording VTR 33 as required on the dubbing tape 34. Edited and recorded.

That is, the reproduction VTR 32 of the dubbing device 31 reproduces the recorded color difference signal S21 from each color signal track of the first tape through the reproduction head 35, further through the reproduction amplifier circuit 36, and supplies it to the frequency demodulation circuit 37, thereby multiplexing it. The color difference signal 514 (Fig. 4 ω)) is demodulated into components, and the recorded luminance signal S22 is reproduced from the 14-degree multiplied track of the first tape B via the playback head A and further via the playback amplification circuit 39 to determine the frequency. By supplying it to the demodulation circuit 40, the luminance signal 515 (FIG. 4(A)) is recorded as a component.

The reproduced multiplexed color difference signal 823 and reproduced luminance signal SM obtained as component signals in this manner are respectively provided to the recording VTR 33 of the dubbing device 31. This recording VTR 33 frequency-modulates the reproduction multiplexed color difference signal S in a frequency modulation circuit 41, and then records the components on the signal track of the dubbing tape 34 via a recording amplifier circuit 42 and a recording head 43. After frequency modulation is performed in a frequency modulation circuit 44, the brightness of the dubbing tape 34 (component recording f is performed on track i) via a recording amplification circuit 45 and a recording head 46.

In addition, the dubbing device 31 connects dropout detection circuits 47 and 48 to the output terminals of the regenerative amplifier circuits 36 and 39, so that dropouts occur in the regenerated multiplexed difference signal s21 and new signal 822. The dropout detection signal 825 and S2 are comprised of pulses having a period of time (meaning the time of occurrence and the time of end IM).
6 is generated and given as a mute signal to the recording/amplifying circuits 42 and 45.

At this time, the recording amplification circuits 42 and 45 are controlled to perform amplification operation when the dropout detection signals S25 and 326 rise, and the dropout of the reproduced multiplex 1 color difference signal S21 and the irregular luminance signal S22 occurs. σ) Interval button A5-S Z'i and s2 from the time of occurrence to the end time
8 is regulated to, for example, the rOJ level.

In this way, when a dropout occurs in the reproduced multiplexed color difference (g signal S21 and reproduction luminance 1g signal S22), a dropout signal corresponding to the section is recorded on the dubbing tape 34.This dropout signal is detected when the dubbing tape is reproduced by the V 1' R apparatus for reproducing red tape, as will be described later, and is corrected by the dropout correction circuit of the VTR apparatus for reproducing.

When playing back the dubbing tape formed by component recording the video signal obtained from the first tape, this dubbing tape 34 is run on the playback VTR device 51, and the playback VTR device 51 plays back the recorded components. A composite output video signal is played back and output based on the video signal.

That is, the reproduction V'lR device 51 reproduces the recorded color difference 1g signal S31 from the dubbing tape's signal track through the reproduction head 52 and further through the reproduction amplifier circuit 53 and supplies it to the frequency demodulation circuit M, thereby producing a multiplexed color difference, Signal S
32 is component-demodulated and this reproduced multiplexed difference signal S32 is given to the component signal reproduction circuit 55, and the recorded luminance signal S33 from the luminance signal track of the dubbing tape is further transmitted through the reproduction head 56'f3:: to the reproduction amplifier circuit 57. The luminance signal S34 is component-demodulated by being reproduced and supplied to the frequency demodulation circuit 58, and this reproduced luminance No. 16 S34 is supplied to the component signal reproduction circuit 55. Furthermore, the reproduced amount demodulated by the demodulation circuits 54 and 58 [the Y/C timing signal generation signal P2 and the synchronization pulse signal PI inserted into the modified difference signal S32 and the reproduced luminance signal S34, respectively (Fig. 4(B)
) and (a) are separated in the synchronization separation circuit 59 and (a) and applied to the timing signal generator l1gl161 of the component code reproduction circuit group. A reference video signal S35 is given to this timing signal generation circuit 61 as an external synchronization signal, and the processing operations of the luminance signal Y and R-Y, B-Y color difference signals in the component signal reproducing circuit 55 are synchronized with the reference video signal S35. It is designed to generate a timing signal to cause the process to be executed.

As the component signal reproducing circuit, the configuration shown in FIG. 5 can be applied. Component signal regeneration circuit 55
are the reproduced multiplexed color difference signal S32 and luminance signal S34
are received by analog-to-digital conversion circuits 67 and bδ via low-pass filters 65 and 66, respectively, and converted into digital signals, which are then input to digital signal processing circuit 69. The digital signal processing circuit 69 synchronizes the luminance signal 834 reproduced by the timing signal generated in the timing signal generation circuit 61 and the R-Y and B-Y color difference signals included in the reproduced multiplexed color difference signal 832. digitally processed. That is, the analog-to-digital conversion circuit 67 and the data generated by the timing signal generation circuit 61 are sequentially converted into digital data at predetermined timings using sample pulses S37 and 838, and the obtained data is applied to the digital signal processing circuit b9.

The digital signal processing circuit 69 has a brightness of 4. The digital data of m@Y is applied to the time axis correction circuit 71 via the dropout compensation circuit 70. The drop-out flit compensation circuit 70 has a built-in IH memory that stores digital data of the luminance signal Y at each sampling point in one horizontal opening period H, and stores the digital data of the luminance signal Y at each sampling point in one horizontal opening period H. The digital data of the horizontal synchronization period is stored. On the other hand, the luminance signal regeneration amplifier circuit 5
A dropout detection circuit 72 is connected to the output terminal of 7 (ω) in FIG. A dropout detection signal S39, which is a pulse signal with a width of 1000 nm, is applied to the dropout compensation circuit '70. At this time, the dropout compensation circuit 70 reads digital data at a sample time corresponding to the rising portion of the dropout detection signal S39 from the IH memory in one horizontal opening period currently being processed, and drops it. It is inserted as replacement data for the data 1, thus compensating for dropouts.

The luminance signal Y thus compensated in the dropout compensation circuit 70 is given to the time axis correction circuit 7e. The time axis correction circuit 71 is arranged such that the leading edge of the synchronizing pulse signal Pi (FIG. 4(A)) included in the reproduced luminance signal S33 is before the horizontal synchronizing signal of the reference video signal S35, which is given as an external synchronizing signal. The time axis of the luminance signal Y in each horizontal opening period is corrected so that it occurs at the same time as the edge, thereby eliminating fluctuations in the time axis such as jitter that occur in the luminance 4g Y reproduced from the dubbing tape 34. do.

In this way, the luminance signal Y is dropout compensated and time axis corrected in the digital signal processing circuit 69.
is converted into an analog signal in the digital-to-analog conversion circuit 73, and then passed through the low-pass filter 74,
Further, the signal is sent to a combining circuit 76 via a delay circuit 75.

In addition, the digital (m-th processing circuit 55 receives the multiplexed color difference signal <
The digital data of R−y>·(B−Y) is applied to the color difference signal time axis correction separation and expansion circuit 77. The color difference Ig time axis correction separation and expansion circuit 77 receives the reproduced multiplexed color difference signal S3.
Y/C timing node P2 included in 1 (Fig. 4 ■
) of the synchronizing pulse signal PI (FIG. 4 (4)) included in the reproduced luminance signal 833.
By correcting the time axis of the digital data for one horizontal opening period so as to match the rising time of the edge, the multiplexed color difference signals (R-Y) and (B-Y) are synchronized with the luminance signal Y and jitter is eliminated. to remove. The circuit 77 then outputs the compressed R-Y color difference signal and B-Ye difference No. 1g is separated and extended to twice the time axis, and then the extended R
Synchronize the -Y color difference signal and the B-Y color difference signal and apply them to dropout compensation circuits 78 and 79, respectively.

1 to each of the dropout correction circuit 78 and the dropout correction circuit 9.
IH that stores digital data of the color difference signals R-Y and B-Y at each sampling point in the horizontal opening period H
It has a built-in memory, and this IH memory stores digital data of a horizontal synchronization interval before the IH of the horizontal synchronization interval currently being processed. On the other hand, a dropout detection circuit lf'<80 is connected to the output terminal of the 9-width circuit 53 (Fig. 2 (B)),
Color difference signal and B-Y1! ! When there is a dropout in the difference signal, this dropout section (considering the point of occurrence and its time width) is determined by the Y/C timing pulse deviation P2.
#41 is detected using the rising edge of the trailing edge as a reference, and the data of the detection result is doubled by one vertical axis and is output as a dropout detection signal S40 to the dropout supplementary angle circuits 78 and 7'.
:) at the same time. Incidentally, in Fig. 4, when dropout occurs in the section of compression RY color difference Ig, the compression start time t3 is set as an indicator to detect the occurrence and end of dropout, and double this. A pulse that rises and falls at a time point extended along the time axis is sent out as a dropout detection signal 840. When a loose dropout occurs in the section of the pressure part B-y2 difference number, the occurrence and end time of the dropout are detected based on the compression start time t3, and the compression R is started from this occurrence and end time. = The end point L4 of the Y color difference signal is subtracted, and the pulses that rise and fall at the point in time when the result of this subtraction is extended to twice the time axis are sent out as the drombout detection signal 840.

As a result, the expanded R-Y and B-Y color difference signals of one horizontal period obtained in the circuit 77 are processed twice as long as the compressed R-Y or B-Y color difference signals in which dropouts have occurred. The data before IH is inserted during the section corresponding to the occurrence and end of the dropout when the data is expanded to [sum]. Here, even if the data insertion operation occurs in one of the compressed R-'YY color-difference signals and the expanded B-Y color-difference signal, the data is inserted into both the expanded R-'YY color-difference signal and the expanded B-Y color-difference signal. The insertion is performed so that no deviation occurs in the data thus inserted.

In this manner, the expanded R-Y and B-Yf! are subjected to time axis correction, expansion, separation, and dropout correction in the digital signal processing circuit 55! ! + difference signal is clock pulse S in digital-to-analog conversion circuits w-81 and 82.
After being converted into an analog signal by 41, it is applied to a color signal encoder 85 via low-pass filters 83 and 84. The color signal encoder encodes the color signal C using the reference subcarrier and sends this color signal C to the synthesis circuit 16 via the bandpass filter 86.

A combining circuit 76 receives the applied luminance signals Y and RY.

The B-Y color difference signal is synthesized and a reference video signal RE is applied thereto via the timing signal generation circuit 61.
Composite output video signal S4 with FSYNC added
Send as 2.

In the above configuration, the reproduction VTR of the dubbing device 31
32, when a dropout occurs in the reproduced luminance signal 822 or the reproduced multiplexed color difference signal S21 reproduced from the first tape okara, a dropout detection signal is generated that indicates the time point at which the dropout occurs and the time until it ends corresponding to the dropout section. 826 and S25 are dropout detection circuits 48
and 47, and this.

is given to the recording amplifier circuits 45 and 42 of the recording VTR 33 as a mute signal. Therefore, when a dropout occurs on a dubbing tape, a "0" level is recorded during that section. However, this dropout is expressed in the VTR device 51 for dubbing tape playback.
, the dropout compensation circuit 70, 18 .
Repaired by 79.

Accordingly, depending on the configuration of FIG. The configuration of the device can be further simplified.

In the reproducing VTR 51 shown in FIG. By compensating for data in corresponding signal portions of both the R-Y color difference signal and the B-Y color difference signal, the possibility of color shift occurring in the composite output video signal 842 can be alleviated. I can go there.

In the above description, the RY signal and the B signal are used as the e running signal.
Although the case where the -y signal is used has been described, it is also possible to use the engineering signal and the Q signal instead.

Furthermore, in the above description, two component video signals of the component video year, namely R-y and B
-Y color difference signal is compressed and multiplexed, but when three or more component video signals are compressed and multiplexed, for example, luminance signals Y, R-Y and B-
The present invention can also be applied to the case where a set of Y color difference signals and a set of R, G, and B primary color signals are compressed and multiplexed in the same manner as in the above case.

〔Effect of the invention〕

As described above, according to the present invention, when a dropout occurs in at least a part of a plurality of compressed and multiplexed component video signals, an expanded component video signal obtained by expanding and separating the component video signals By performing dropout compensation on the signal portion corresponding to the dropout section, dropout compensation can be performed without destroying the relationship between the component video signals.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating a conventional recording and reproducing device, FIG. 2 is a block diagram showing an embodiment of the recording and reproducing device β according to the present invention, and FIGS. 3 and 4 show its compression processing operation. FIG. 5 is a block diagram showing the detailed configuration of the component signal reproducing circuit of FIG. 2. 15...Camera unit, 16...VTR device for recording, 17...Synchronization No. 4g circuit, 18...Time axis correction expansion circuit, 19, 24...Synchronization signal addition circuit, c.・
- First tape, 31...dubbing device, 32...
VTR for playback, 33...VTR for recording 134...Dubbing tape, 47.48...Dropout detection circuit, 51...VTR device for playback, 55...Component signal playback circuit, 59, 60. ... 111 minutes for the same period
circuit, bl...timing signal generation circuit, 69...
・Digital signal processing circuit, 70, 78, 79...
- Dropout compensation circuit, 71... Time base correction circuit, 72, 150... Dropout detection circuit, 7e
... Synthesis circuit, 77 ... Time axis correction expansion circuit, 85
... p 4K encoder. Applicant's agent Megumi Debe

Claims (1)

[Claims] A video signal recording/reproducing method in which a plurality of component video signals are time-axis compressed, multiplexed in time series in one horizontal period interval, and recorded, and the plurality of component video signals are obtained by separating and synchronizing the plurality of component video signals at the time of playback. The apparatus detects a dropout section from the plurality of reproduced component video signals, and detects a dropout section corresponding to the dropout section for the plurality of separated and synchronized component video signals according to the dropout section detection signal. A video signal recording and reproducing device characterized by compensating for partial dropouts.