JPH031695A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain high picture quality for a picture even when the picture is reproduced on an IDTV (high quality TV receiver) by providing a time base fluctuation correction device (TBC) provided with a luminance signal correction means and with a color signal correction means or the like and a color signal filter means or the like. CONSTITUTION:A reproducing signal from a switcher 5 supplied to a luminance signal reproducing circuit 6 and a color signal reproducing circuit 7 is inputted to a TBC 13. Then the TBC 13 generates and outputs a luminance signal Y and a chrominance carrier signal C' whose time base fluctuation is corrected via a write control circuit 9, a readout control circuit 10, a decoder 11, an encoder 12 and line memories 8, 8''. Then the signal C, is supplied to a C type frame correlation comb-line filter 16, the signal is retarded by one frame at a frame memory 14, subtracted by a subtraction circuit 15 to eliminate the component not inverted for each frame and to extract the component inverted for each frame. Then the chrominance carrier signal C from which a disturbing signal is eliminated is outputted from the filter 16 and added to a signal Y at an adder circuit 17 and a color video signal with high quality is outputted from an output terminal 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal recording and reproducing apparatus equipped with a time base variation correction device (TBC).

[Prior art] The luminance signal of a color video signal is frequency modulated (FM), the carrier color signal is frequency-converted to a low frequency band, and the obtained FM luminance signal and the low-frequency converted carrier color signal are multiplexed and recorded and reproduced. In video signal recording and reproducing apparatuses (hereinafter referred to as VTRs) using the so-called carrier color signal low-band conversion recording method, time axis fluctuations occur in this multiplexed signal due to recording and playback. is frequency-converted to a carrier color signal of the original color subcarrier frequency using a carrier with the same time axis variation, so the time axis variation is removed from this carrier color signal, and a normal color reproduction image is obtained. It will be done.

However, recently, VTRs have become increasingly high-band, recording and reproducing luminance signals over a wider band.

Along with this, fluctuations in the playback screen due to time axis fluctuations in the luminance signal are becoming more noticeable. In addition, there is a growing need for editing by combining VTR playback images with images from other video sources. Shaking due to time axis fluctuations in the reproduced image becomes very noticeable.

For this reason, it has become necessary to correct temporal axis fluctuations in the reproduced luminance signal as well.

An example of a VTR that solves this problem is the Television Society journal "Television", Vol. 31, No. 10 (197
7) pp. 771-'17'l.

This is a VTR that uses a carrier color signal low frequency conversion recording method, with a TBC installed on the playback side.

A composite color video signal of an FM-demodulated luminance signal and a high frequency-converted carrier color signal is supplied to the TBC to remove time axis fluctuations.

By the way, in recent years, I D TV (I improve
High-definition television receivers called d Definition TV are becoming popular. This does not change the current broadcasting system and aims to improve vertical resolution by making it non-interlaced, but it separates the luminance signal and carrier color signal from the input color video signal (hereinafter referred to as
As a means for this (Y/C separation), a frame correlation comb filter and a line correlation comb filter are provided, and the input color video signal is af! If the signal is an 8 format signal, a frame correlation comb filter is used to perform Y/C separation, but if the signal is a non-standard format signal, a line correlation comb filter is used to perform Y/C separation. ing. Whether the input color video signal is of a standard format or a non-standard format is determined based on, for example, the ratio between the horizontal synchronization frequency and the color subcarrier frequency of the input color video signal.

Therefore, when supplying a reproduced color video signal from a VTR using the carrier color signal low frequency conversion recording method to an IDTV, this VT
When TBC is not provided in R, this reproduced color video signal is in a non-standard format, so in IDTV, a line correlation comb filter performs Y/C separation, but this V
When the TR is provided with a TBC, the reproduced color video signal is of the standard format, and in IDTV, Y/C separation is performed using a frame correlation comb filter.

Here, the functions of the line correlation comb filter and the frame correlation comb filter will be explained.

FIG. 10(a) shows the 1fH region (where f is the horizontal synchronization frequency) in the frequency band including the carrier color signal of the color video signal. Here, the Q mark represents the frequency component of the luminance signal Y, and one frequency is centered around the frequency component (hereinafter referred to as nfH component) of nfH (where n is an integer) at intervals of 2 fp (where fF is the frame frequency). Frequency components are present. That is, lI! ! 1 degree signal Y
The frequency components of are in phase for 1H (where 1H is one horizontal period).

In addition, the mark indicates the frequency component of the carrier color signal.

Frequency components exist at frequency intervals of 2 fF with the center at 2 fF. That is, the phase of the frequency component of the carrier color signal C is inverted between IHs. Therefore, as shown, the frequency components of the carrier color signal C are present between the frequency components of the luminance signal Y, and the carrier color signal C is frequency interleaved with the luminance signal Y.

FIG. 10(b) shows the pass characteristics of the line correlation comb filter. The solid line shows the pass characteristic of a so-called Y-shaped line correlation comb filter for extracting a luminance signal. This is the minimum characteristic.

When a color video signal is supplied to this Y-shaped line correlation comb filter, due to the characteristics shown by the solid line in Fig. 10(b), the frequency components shown in Fig. 10(C) are
As shown in FIG. 2, frequency components near the nf component are extracted, and a luminance signal consisting of such frequency components is obtained.

However, this luminance signal includes frequency components of the carrier color signal near the nfH component. Furthermore, when a color video signal is supplied to a C-shaped line correlation comb filter, the first
According to the characteristics shown by the broken line in FIG. 0(b), the frequency component of the frequency shown in FIG. 0(a) is extracted, and a carrier color signal consisting of such components is obtained. However, this conveyance color is believed.

Note that the Y-shaped line correlation comb filter is composed of an IH delay means (where IH is one horizontal period) and an addition circuit.
The C-type line correlation comb filter is composed of an IH delay means and a subtraction circuit.

FIG. 11 shows the action of the frame correlation comb filter, and FIG. 11(a) shows the color video signal shown in FIG.
It represents the same frequency range as a).

The solid line in FIG. 11(b) shows the pass characteristic of a so-called Y-shaped frame correlation comb filter for extracting the luminance signal Y, and nfR±2mfF (however, m=o, 1
,2. .

The dashed line shows the pass characteristic of a so-called C-shaped frame correlation comb filter for extracting the carrier color signal C, and has a maximum at a frequency of f, ±2mfp and a minimum at a frequency of nf□±2mfp. It has become a characteristic.

According to this Y-shaped frame correlation comb filter, the first
From the frequency components shown in FIG. 1(a), only the frequency components indicated by 0 marks are extracted, and as shown in FIG. 11(c), a luminance signal Y in which the frequency components of the carrier color signal C are not mixed is obtained. ,
Moreover, according to the C-shaped frame correlation comb filter, only the frequency component indicated by the mark . is extracted from the frequency components in FIG. A conveyed color signal without contamination of components can be obtained.

Since the line correlation comb filter and the frame correlation comb filter operate as described above, in IDTV, when the input color video signal is Y/C separated by the frame correlation comb filter, the m degree signal Y and the carrier color signal are separated. C is completely separated, and a reproduced image with good image quality can be obtained.

[Problems to be Solved by the Invention] By the way, the conventional V
In TR, a line correlation comb filter is used as the Y/C separation means. For this purpose, as explained in FIG. 10, the separated luminance signal includes the carrier color signal C.
The frequency components of the luminance signal Y remain, and the frequency components of the luminance signal Y remain in the separated carrier color signal. These luminance signals and carrier color signals are processed and recorded as described above, reproduced, subjected to predetermined reproduction processing, synthesized, and time-base corrected by TBC as a color video signal. This color video signal is
When supplied to the DTV, since this color video signal has been time-base corrected by the TBC, the IDTV determines that it is a standard format signal and uses the frame correlation comb filter to
/C separation is performed.

However, as shown in FIG. 10(d), the carrier color signal recorded and reproduced in a VTR is a luminance signal Y marked with an O mark.
If the residual component is indicated by an X mark, the color video signal output from the TBC is expressed as shown in FIG. 12(a). Note that the frequency component of the carrier color signal C mixed into the luminance signal shown in FIG. 10(c) is also included.

Similarly, residual components are indicated by X marks.

Such color video signals are used in IDTV.

When Y/C is separated by the frame correlation comb filter, the resulting luminance signal is +2 as shown in FIG. 12(b).
n+1 As shown, the residual component (X mark) mixed into the carrier color signal shown in FIG. 10(d) near the frequency of 2 fH.
will be included.

2n+1 There is no problem if these residual components are the same as the frequency components of the luminance signal near the frequency of 7fH in FIG. 10(a). However, these residual components cause the recording of the carrier color signal,
It has been processed by a reproduction processing circuit, and therefore its level and phase change depending on the characteristics of these processing circuits, and it does not become a frequency component of a luminance signal. Rather, this residual component becomes an undesirable noise component in the luminance signal, interfering with the reproduced image and significantly deteriorating the image quality. When we actually evaluated a prototype VTR, we found that
It has been found that in DTV, interference appears in image portions corresponding to the edge portions of the luminance signal.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video signal recording and reproducing apparatus that solves these problems and allows high-quality reproduced images to be obtained even when the images are reproduced on an IDTV.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a filter means for extracting a component that is inverted for each frame from a reproduced carrier color signal whose time axis fluctuations have been corrected.

Further, the present invention further provides that in the carrier color signal low range conversion recording method, a first . A phase converting means for making the phase difference between the second fields different by 180 degrees, and a phase restoring means for making the phase difference of the low frequency converted carrier color signal to be reproduced equal.

[Operation] As described above, the reproduced carrier color signal includes a frequency component of the luminance signal that is not inverted for each frame, and by supplying the carrier color signal to the filter means, This component is removed, and only the component, which is originally the frequency component of the carrier color signal and is inverted every frame, is obtained.

therefore.

Even if the output signal of the filter means is combined with the luminance signal, the luminance signal does not contain interference signals that degrade image quality.

Furthermore, during reproduction using the carrier color signal low-band conversion recording method, the low-band converter carrier color signal of the adjacent track is mixed into the reproduced low-band converter carrier color signal as crosstalk. On the other hand, in the carrier color signal low-frequency conversion recording method, the phase of the low-frequency conversion color signal is changed for each IH, and the direction of change in the phase is reversed for each field (that is, for each track). . According to this, the direction of phase change is different between the reproduced low frequency conversion carrier color signal and the gross talk mixed therein. However, the direction of change in the phase of the low frequency conversion carrier color signal between frames is the same, and the same applies to crosstalk.

By the way, according to the above-mentioned phase conversion means, the phase of either the low-frequency conversion color signal or the crosstalk is always reversed from frame to frame. Therefore, if the above-mentioned phase change and phase difference caused by the phase conversion means are eliminated for the reproduced low-frequency converted color signal, the crosstalk between each frame will be 180% with the carrier color signal as the phase reference. The phase will be different, resulting in a component that does not invert every frame.

Therefore, by passing the carrier color signal through the filter means, the cross 1-1 can be removed.

The line 4n comb filter conventionally used to remove crosstalk becomes unnecessary.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a reproduction system of an embodiment of a video signal recording and reproduction apparatus according to the present invention, in which ■ indicates a magnetic tape;
2 is a rotating cylinder, 3, 3' is a video head, 4.4'
is a regenerative amplifier, 5 is a switcher, 6 is a luminance signal regeneration circuit, 7 is a color signal regeneration circuit, 8.8', 8'' is a line memory, 9 is a write control circuit, 10 is a readout control circuit, 11 is a decoder, 12 is an encoder, 13 is a TBC 114 is a frame memo! 15 is a subtraction circuit, 16 is a frame correlation comb filter, 17 is an addition circuit, and 18 to 2o are output terminals.

In the figure, a rotary cylinder 2 is provided with video heads 3, 3' at an interval of 180a, and a magnetic tape 1 is wound around the rotary cylinder 2 over approximately 180 degrees and runs. On the magnetic tape 1, a multiplexed signal of an FM luminance signal and a low frequency conversion carrier color signal is recorded one field on each track. The rotary cylinder 2 rotates at the cycle of one frame of the video signal, so that the video heads 3 and 3' alternately scan the magnetic tape 1 one track at a time.
Play and scan. Reproduction signals from the video heads 3 and 3' are amplified by reproduction amplifiers 4 and 4', respectively, and are spliced by a switcher 5 into a continuous signal.

The reproduction signal from the switcher 5 is supplied to a luminance signal reproduction circuit 6 and a color signal reproduction circuit 7. In the luminance signal reproducing circuit 6, the FM luminance signal is separated from the reproduced signal, subjected to processing such as demodulation, and outputted as a baseband luminance signal to the TBC 13. In the color signal reproducing circuit 7, the low frequency conversion carrier color signal is separated from the reproduced signal, and processing such as frequency conversion is performed to convert the carrier color signal of the color subcarrier frequency to TBC.
13.

In the TBC 13, the write control circuit 9 generates a write signal synchronized with the synchronization signal separated from the brightness signal by the brightness signal reproducing circuit 6, and the read control circuit 10 generates a read signal of a constant frequency. Luminance signal regeneration circuit 6
The luminance signal supplied from the 7th write signal is written into the line memory 8 by this 7 write signal, and is read out by this read signal to obtain a luminance signal Y whose time axis fluctuations have been corrected.

Further, the carrier color signal supplied from the color signal reproducing circuit 7 is
The decoder 11 generates two baseband color difference signals R.
-Y, BY demodulated. These color difference signals R-Y, B
-Y is written to the line memories 31 and 811 by the write signal from the write control circuit 9, respectively, and the read control circuit 1
It is read by a read signal from 0. Color difference signals R-Y and B-Y read out from line memories 8# and 871
are supplied to the encoder 12, modulated and added to generate the carrier color signal C' again.

This carrier color signal C' is applied to a C-shaped frame correlation comb filter 16. In the frame correlation comb filter 16, the supplied carrier color signal C' is delayed by one frame in the frame memory 14, and the carrier color signal C' is subtracted from the carrier color signal C' in a subtraction circuit 15. As a result, components that are not inverted for each frame of the carrier color signal CI are removed, and components that are inverted for each frame are extracted.

As mentioned above, in the carrier color signal low-pass conversion recording method, a line correlation comb filter is used for Y/C separation in the recording system, and for this reason, as shown in FIG. 10(d), In the carrier color signal C' outputted from the TBC 13, the frequency component of the luminance signal (marked with a circle) remains as an interference signal.

However, this interference signal does not invert from frame to frame and is removed by the frame correlation comb filter 16. On the other hand, the frequency component of the carrier color signal (marked with * in FIG. 10(d)) is a component that is inverted every frame.

It passes through a frame correlation comb filter 16. Therefore, the frame correlation comb filter 16 outputs a carrier color signal C from which this interfering signal has been removed.

The luminance signal Y output from the T B Cl 3 and the carrier color signal C output from the frame correlation comb filter 16 are added in an adder circuit 17, and an arts system color video signal is obtained at the output terminal 18. , the luminance signal Y can be outputted from the output terminal 19, and the carrier color signal C can be outputted from the output terminal 20, respectively.

Here, in the color video signal obtained at the output terminal 18,
In the frequency band of the carrier color signal, as shown in FIG. 22n+1 (a), the interference component of nfafmfp is not included in the vicinity of the 2 f, (7) frequency. Therefore, when this color video signal is supplied to the IDTV, the luminance signal separated by the frame correlation comb filter does not contain any interference signal, as shown in Figure 2(b). Become. Therefore, a reproduced image of high quality and without shaking can be obtained.

In the color signal reproducing circuit 7, a PC (automatic phase control) circuit is used, as is well known, when frequency converting the low frequency conversion carrier color signal to a high frequency band. The carrier color signal outputted from the carrier color signal has time axis fluctuations removed. A baseband color difference signal R-Y is demodulated from this carrier color signal.

B-Y is writing in line memories 8' and 8''.

By reading, the write signal from the write control circuit 9 includes time axis fluctuations, but these color difference signals R-Y,
B-Y has a sufficiently low frequency band compared to the luminance signal, so
Color reproduction is not impaired by this time axis variation.

It is conceivable to write and read the carrier color signal from the color signal reproducing circuit 7 in a line memory in the TBC 13, but this would result in fluctuations in the time axis in the carrier color signal output from now on, and the frame correlation comb shape The interference signal removal effect of the filter 16 is reduced, and the IDTV no longer determines that the color video signal supplied from the output terminal 18 is a non-standard signal. On the other hand, in this embodiment, since the encoder 12 encodes using a standard color subcarrier with no time axis variation, the interference signal removal effect of the frame correlation comb filter 16 is fully demonstrated.
Moreover, the color video signal at the output terminal 18 is a standard format signal.

FIG. 3 is a block diagram showing a reproduction system of another embodiment of the video signal recording and reproduction apparatus according to the present invention, in which 21 is a frame memory, 22 is an adder circuit, 23 is a frame correlation comb filter, and the first Portions corresponding to the figures are given the same reference numerals and redundant explanations will be omitted.

As is clear from the explanation of FIG. 10, in the luminance signal separated by the line correlation comb filter.

Frequency components of the carrier color signal (first
In Figure 1, this is also mixed into the luminance signal Y output from the TBC 13 as an interference signal (marked with an x in Figure 2 (a)). ). In IDTV, this interference signal is not included in the luminance signal separated by the Y-shaped frame correlation comb filter, but remains in the carrier chrominance signal separated by the C-shaped frame correlation comb filter.

In FIG. 2, the luminance signal Y+J output from TBC13
This interference component is removed by passing the signal through a Y-shaped frame correlation comb filter 23.

Since the interference signal mixed in the luminance signal Y is a frequency component of the carrier color signal, it is inverted every frame. Further, in the frame correlation comb filter 23, the luminance signal Y is delayed in the frame memory 21, and this and the luminance signal Y are added together in the adding circuit 22. As a result, components that are inverted for each frame are removed, and components that are not inverted for each frame are extracted. Therefore, the frame correlation comb filter 23 provides a luminance signal Y from which interference components have been removed.

In this way, as shown in FIG. 4(a), the output terminal 18 is provided with a color video signal that does not contain interference signals either near the frequency nfH or near 2n+12f8.
In the IDTV to which this color video signal is supplied, a C-shaped frame correlation comb filter provides a carrier color signal that does not contain interference components, as shown in FIG. 4(b). Therefore, the quality of the reproduced image is further improved.

In the above embodiment, the VT of the carrier color signal low frequency conversion recording method is used.
Although R is used as an example, it is not limited to VTRs, and any video signal recording and reproducing device can be used as long as it separates and processes the recording luminance signal and the carrier color signal. Good too.

By the way, in a VTR of carrier color signal low frequency conversion recording system, the low frequency conversion carrier color signal of the adjacent track is mixed into the reproduced low frequency converted transmission signal as crosstalk. In order to eliminate this, the phase of the low frequency conversion carrier color signal is changed for each IH during recording, and the direction of the phase change is changed by 1.
It is inverted for each track, and during playback, the phase is restored when the frequency of the low-frequency converted carrier color signal is converted to a high frequency band, and the reproduced carrier color signal processed in this way is passed through a C-shaped line correlation comb filter. That's what I do. The crosstalk mixed into this reproduced carrier color signal is removed by the line (
1H), and the C-type correlation comb filter passes components that are inverted for each line. Therefore, this line correlation comb filter removes crosstalk from the reproduced carrier color signal. can do.

In this way, VTRs using the conventional carrier chrominance signal low frequency conversion recording system are equipped with line correlation comb filters for eliminating crosstalk, but as shown in Figures 1 and 3 below, interference An embodiment of the video signal recording and reproducing apparatus according to the present invention in which the C-shaped frame correlation comb filter 16 for component removal can also be used for crosstalk removal will be described with reference to FIGS. 5 and 6. However, FIG. 5 is a block diagram showing the recording system, and 24 is an input terminal, 25 is a frame memory, 26 is an addition circuit, 27 is a subtraction circuit, 28 is a comb filter, 29 is a luminance signal recording circuit, and 30 is an adder circuit, 3
1 is a recording amplifier, 32 is a color signal recording circuit, 33 is a converter, 34 is an APC circuit, 35 is a converter, and 36 is an A
FC (automatic frequency control) circuit, 37 is BPF (band pass filter), 38 is phase shift circuit, 39 is selector, 4
0 is an LPF (low pass filter), 41 is an initial value setting circuit, and 42 is a ring counter. Further, FIG. 6 is a block diagram showing the reproduction system, in which 43 is an LPF, 44
is a converter, 45 is a BPF, 46 is an AFC circuit, 47
is OSC (oscillator), 48 is converter, 49 is BPF
, 50 is a phase shift circuit, 51 is a selector, 52 is an initial value setting circuit, 53 is a ring counter, 54 is a phase difference detection circuit,
55 is an IH delay circuit, 56 is a subtraction circuit, 57 is a line correlation comb filter 1, and 58 is a switch. In FIGS. 5 and 6, parts corresponding to those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

First, in FIG. 5, an NTSC color video signal is inputted to an input terminal 24, and is supplied to a comb filter 28 where it is separated into a baseband luminance signal Y and a carrier color signal C. Here, the comb filter 28 is a frame correlation comb filter consisting of a frame memory 25, an addition circuit 26, and a subtraction circuit 27.
5 and the addition circuit 26 constitute a Y-shaped frame correlation comb filter, and the frame memory 25 and the subtraction circuit 27 constitute a C-shaped frame correlation comb filter.

However, by using a line memory instead of the frame memory 25, the comb filter 28 may be a line correlation comb filter.

The luminance signal Y is subjected to processing such as FM modulation in the luminance signal recording circuit 29, and an FM luminance signal YFM is generated and supplied to the addition circuit 30.

Further, the conveyed color signal C is supplied to the color signal recording circuit 32. In the color signal recording circuit 32, the carrier color signal C is supplied to a converter 33 and also to an APC circuit 34, where a continuous signal of 3.58 MHz is formed in synchronization with the burst signal.

Further, the horizontal synchronizing signal H3 of frequency f8 separated from the luminance signal Y by the luminance signal recording circuit 29 is supplied to the AFC circuit 36, and a continuous signal of 629 kHz is generated in synchronization with this signal. The output signal of the APC circuit 34 and the output signal of the AFC circuit 36 are supplied to the converter 35, and 4.21
A continuous MHz signal is generated. This signal has unnecessary components removed by a BPF 37 having a center frequency of 4.21 MHz, and is supplied to a phase shift circuit 38. This phase shift circuit 38 is sequentially 90
Outputs four signals with frequencies of 4 and 21 MHz, each with a different phase.

On the other hand, the ring counter 42 counts the horizontal synchronizing signal H8 from the luminance signal recording circuit 29 and outputs a control signal for the selector 39. Further, the brightness signal recording circuit 29 outputs a 30Hz signal 5W30 whose level is inverted every time the video heads 3, 3' scan the magnetic tape 1, and thereby the video heads 3, 3' start scanning the magnetic tape 1. At this timing, the ring counter 42 resets the initial value setting circuit 41.
The initial value is set and the direction of counting is reversed.

The selector 39 is controlled by the output of the ring counter 42 and carries any of the four output signals from the phase shift circuit 38, but the count value of the ring counter 42 and the output signal of the phase shift circuit 38 correspond one-to-one. and selector 3
9 selects the output signal of the phase shift circuit 38 corresponding to the count value output by the ring counter 42.

Now, one output signal of the phase shift circuit 38 is set to φ with a phase of 0°.

Binding, sequentially 90°, 180'', 270''
' Output signal with delayed phase φ901 φ□ant φ2
□. shall be.

Further, the ring counter 42 outputs count values of 0, 1, 2, and 3, and the selector 39 outputs a signal φ when the count value is O. Hereafter, when the count value is 1.2.3, the signals φ9°, φ, 8o, φ2□. shall be selected respectively.

Ring counter 42 is activated by signal 5W30.

Up-counting operation for each track (1 field),
The count direction is reversed by switching alternately with the down count operation. Therefore, now, the ring counter 42 is set to count up during reproduction scanning of a certain track (field), and...0.1, 2, 3, etc. O,・
Assuming that you are counting repeatedly,
The selector 39 is...φ. .

φ98. φ1801 φ27o, φ. , . . . The output signals of the phase shift circuit 38 are selected in the order of . ,2,1. O.

... is counted as Jllll(, and selector 39 is...
..., φ. .

φ21. ．． φ, 8°, φ,. ,φ. , . . . , the output signals of the phase shift circuit 38 are selected in this order. If the phase of the output signal φ of the selector 39 is delayed by 90' for each IH in a certain track scanning period, the phase advances by 906 for each IH in the first track scanning period.

The above is the same as the P S (Phase 5 shift) system adopted in the conventional so-called VH8 system VTR, but in this seventh embodiment, the initial value setting circuit 41
By using , the initial phase of the output signal φ of the selector 39 in each field is defined.

That is, the initial value setting circuit 41 operates at the edge of the signal SW30 and sets the initial value in the ring counter 42. The initial value in each field is the first value for each frame of the carrier color signal C. The phase difference of the output signal φ of the selector 39 within the second two field periods is set to be different by 180°.

- As an example, in a certain frame of the carrier color signal C, the first . Assuming that the initial value O at the start of the second field is set in the ring counter 42, in the next frame,
The initial value at the start of the first field is 0, and the second
The initial value at the start of the field is set to 3 in the ring counter 42. As a result, in the above-mentioned certain frame, the output signal φ of the selector 39 is φ in the first field. , φ91+1φ□,. , φ2□. ,...
・The phase is delayed by IH in the order of φ in the second field. .

φ27o, φ□801 φ,. ,...I in order
The phase advances by H, and the 1st. The phase difference between the second fields is O'-180',O', +180@-
---・- changes for each IH. In the next frame,
φ in the first field. ,φ,. , φx, lot φ
The phase is delayed by IH in the order of 27°, . . ., but in the second field, φ1s0. φ,. ,φ. ,φ2
□. , . . . The phase advances by lH in this order.

Therefore, the phase difference between the 1st and 2nd fields is +
180'', O'-180°lo'l......and changes for each IH. Therefore, between these two frames, the phase difference between the first and second fields is 180'.
It will be different.

The output signal φ of the selector 39 whose phase changes in this way is supplied to the converter 33, and the carrier color signal C is frequency-converted into a low-band converted carrier color signal CL (with a color subcarrier frequency of 629 kHz.This low-band conversion The carrier color signal CLc has unnecessary components removed by an LPF with a cutoff frequency of 1.3 MHz, is supplied to an adder circuit 30, and is multiplexed with the FM luminance signal YF□ from the luminance signal recording circuit 29.

It goes without saying that the color subcarriers of the low frequency converted carrier color signals Ct and C undergo the same phase change as the output signal φ of the selector 39.

The multiplexed signal from the adder circuit 30 is amplified by a recording amplifier 31 and then supplied to the video heads 3, 3', where it is recorded on the magnetic tape 1 with one field per track.

Next, in FIG. 6, the switcher 5
A continuous reproduction signal is obtained from the baseband luminance signal, and a baseband luminance signal is separated by the luminance signal reproduction circuit 6 and supplied to the TBC 13. Further, this reproduction signal is supplied to the color signal reproduction circuit 7.

In the color signal reproducing circuit 7, this reproduced signal is 1j3M.
The signal is supplied to an LPF 43 with a cutoff frequency of Hz, where the low-frequency conversion carrier color signal c'Lc is separated and supplied to a converter 44 and a phase difference detection circuit 54. In converter 44, as explained above.

By the output signal φ' of the selector 51 which changes the same phase as the color subcarrier of the low frequency conversion carrier color signal C'LC.

The low-pass conversion carrier color signal C″LC is frequency converted into a carrier color signal of continuous color subcarriers at a frequency of 3.58 MHz,
The signal is supplied to the BPF 45 and unnecessary components outside the band are removed.

The carrier color signal output from the BPF 45 is sent to the AFC circuit 46.
The frequency from ○5C47 is 3.58MH
A continuous signal of 629 kHz is generated which is phase-synchronized with the burst signal of the carrier color signal with reference to the constant signal z. The output signal of the AFC circuit 46 is supplied to the output signal of 08C47 and the converter 48 to generate a signal with a frequency of 4.21 MHz.
After unnecessary components are removed at F49, the signal is supplied to the phase shift circuit 50.

Similar to the phase shift circuit 38 in FIG.
Signals φ′ that differ by 0°. ,φ′,. .

φ′4. . , φ'', 7°. Similarly to the ring counter 42 in FIG. Video head 3.
3' starts scanning the magnetic tape 1 (i.e.,
The up-count operation and down-count operation are alternately switched by the edge of the signal 5W30 whose level is inverted (every track). Similarly to the selector 39 in FIG. 5, the selector 51 also outputs the output signal of the phase shift circuit 50 corresponding to the count value of the ring counter 53.

Here, due to the servo of the VTR, the correspondence relationship between the level of the signal SW30 and the direction of change in the phase of the low frequency conversion carrier color signal C'Lc is determined by the signal 5W30 in the recording system shown in FIG.
and the direction of change in the phase of the low-frequency conversion carrier color signal CLc. For this reason, when the phase of the low frequency conversion carrier color signal C'Lc is delayed by 90' for each IH, the phase of the output signal φ'' of the selector 51 is also delayed by 90° for each IH. When the phase of the signal C'LC advances by 90'' for each IH, the selector 51
The selector 51 adjusts the output signal φ'' of the phase shift circuit 50 so that the phase of the output signal φ' of the phase shift circuit 50 also advances by 90° for each IH.
,. , φ′1. . , φ′27° are sequentially selected.

Further, the phase difference detection circuit 54 outputs a low frequency conversion carrier color signal c'
In Lc, the first . It is determined whether the phase difference between the second fields changes by 180°. When there is a change in this phase difference, the initial value setting circuit 4 in FIG.
The initial value setting circuit 52 similar to 1 is operated, and the signal 5W3 is
0 causes the ring counter 53 to be initialized similarly to the ring counter 42 in FIG. As a result, the first
The phase difference between the second fields is similarly set for the output signal φ' of the selector 51.

In this way, the phase difference of the carrier color signal output from the converter 44 is restored to the original NTSC format, and the A
The output signal of the FC circuit 46 is a low frequency conversion carrier color signal C'LC.
Since the same time axis variation is included, the time axis variation is not included in the moving color signal obtained by the processing of the converter 44.

The carrier color signal output from the BPF 45 is sent to the switch 58.
The signal is supplied to the A side of the switch 58 via the line correlation comb filter 57. The phase difference detection circuit 54 detects that the phase difference between the 1st and 2nd fields is 1 for each frame in the low frequency conversion carrier color signal C''LC.
When an 80° change is detected, switch 58 switches to A.
(Iff is closed, and the carrier color signal output from the BPF 45 passes through the switch 58, is processed by the TBC 13, and is supplied to the frame correlation comb filter 16.

Here, in FIG. 7, if every other frame is the first frame and every other frame is the second frame ((a) in the same figure), then in FIG. 41, as shown in FIG. 7(b), the first . the start point of the second field and the second
0° at the start of the first field of the frame, the second
It is assumed that the phase of the color subcarrier of the low-pass conversion carrier color signal CLc is set to be 180° at the start of the second field of the frame. Note that the arrow indicates the direction of phase change. When such a low frequency conversion carrier color signal CLc is recorded and reproduced, I! l! Track crosstalk is mixed in with the I-contact track, but the phase of the crosstalk at the start of each field of the reproduced low-pass conversion carrier color signal C'LC is shown in Figure 7 (C
). Here, the reproduced low-pass converted carrier color signal C'Lc is shown with a large amplitude and the crosstalk is shown with a small amplitude, but in the first frame, the low-pass converted carrier color signal C'Lc is shown at the beginning of each field. (! and crosstalk are in phase, but in the second frame, they are out of phase in each field.

Here, for each field, the low frequency conversion carrier color signal C'LC
The directions of phase change for each IH of and crosstalk are opposite to each other.

Therefore, by the converter 44 in FIG. 6, the phase of the low-frequency converted carrier color signal c is changed as shown in FIG. 7(c).
Converting 'Lc into a carrier color signal using the NTSC system,
As shown in FIG. 7(d), the phase of the carrier color signal is constant; on the other hand, if the phase of the carrier color signal is used as a reference,
Crosstalk, which indicates the phase of each LH with a small amplitude for each field, has a phase inversion for each IH, and moreover, the phase is inverted between frames.

That is, the crosstalk mixed into the carrier color signal output from the A side of the detection switch 58 becomes a component that is not inverted every frame because the carrier color signal is inverted every frame. This crosstalk is removed.

As described above, when the carrier color signal is processed and recorded and reproduced by the color signal recording circuit 32 in FIG. 5, not only the frequency component of the luminance signal remaining in the reproduced carrier color signal but also the reproduced carrier color signal Crosstalk mixed in can also be removed by the frame correlation comb filter 16. Due to the crosstalk removal effect of the frame correlation comb filter 16, the color spread in the vertical direction of the reproduced image is lower and the image quality is lower than when crosstalk is removed using a conventional line correlation comb filter. It will improve further.

When the magnetic tape 1 recorded on a VTR using the conventional carrier color signal low frequency conversion recording method is reproduced by the reproduction system shown in FIG. By 5W30, the counting direction is simply reversed every track, and the switch 58 is closed to the B side. In this case, the crosstalk mixed in the carrier color signal output from the BPF 45 is not reversed for each IH (based on the phase of the carrier color signal,
As shown in FIG. 7(d), it is reversed for each IH. However, since the signal is not inverted between frames, it is removed by the line correlation comb filter 57. Therefore, the frame correlation comb filter 16 is similar to that shown in FIG.
Similar to the embodiment shown in the figure, the only function is to remove the residual component of the luminance signal mixed in the reproduced carrier color signal.

Note that even when the magnetic tape 1 recorded using the recording system shown in FIG. 5 is reproduced by a VTR using the conventional carrier color signal low-frequency conversion recording method, the comb filter 28 can be replaced with a frame correlation comb filter. In some cases, the frequency component of the luminance signal does not remain in the carrier color signal that is recorded and reproduced, so even if the reproduced color video signal is supplied to the IDTV, no interference occurs in the reproduced image.

In addition, in this embodiment, as shown in FIG. 7, the phase of the low frequency conversion carrier color signal, etc. has been explained using specific numerical values, but this is merely an example for the convenience of explanation. 1
1st for each frame. The phase difference between the second fields is 18
It is sufficient to make the difference by 0°.

Furthermore, in FIG. 6, similarly to the embodiment shown in FIG. 3, a Y-shaped frame correlation comb filter is added, thereby removing interference components mixed in the luminance signal output from the TBC 13. You can do it like this.

Furthermore, in FIGS. 5 and 6, the converter 33
and 44, converters 35 and 48, BPFs 37 and 49, phase shift circuits 38 and 50, selectors 39 and 51, initial value setting circuits 41 and 52. The ring counters 42 and 53 may be the same and used for both recording and reproduction.

In each of the above embodiments, a frame correlated noise reducer using a frame memory as a delay means may be used instead of the frame correlated comb filter 1.6.23. An example of a noise reducer is shown in FIG. Since this operation is well known, it will be omitted, but its characteristics are the same as those shown in FIG. Noise other than signals can also be sufficiently attenuated.

However, especially when using frame-correlated comb filters and frame-correlated noise reducers.

Afterimages due to the movement of one image may be noticeable in the luminance signal. To prevent this, for example, in FIG. 3, a Y-shaped line correlation comb filter 59 is provided in parallel with the frame correlation comb filter 23 (or frame correlation noise reducer) as shown in FIG. , the frame correlation comb filter 2 is normally controlled by a switch 60 controlled by the detection output of a motion detector (not shown).
However, when motion is detected, the brightness signal Y output from the line correlation comb filter 59 may be selected.

Furthermore, in each of the above embodiments, a case has been described in which the PS method is used for the low-pass conversion carrier color signal, but the beta method V
PI (Pha) used in TR, 8mm video, etc.
se Invert) method may be adopted, or
The same applies not only to the NTSC system but also to the PAL system.

[Effects of the Invention] As explained above, according to the present invention, a color video signal with no time axis fluctuation can be obtained, and the occurrence of interference components when displaying an image on an IDTV using the color video signal can be prevented. This enables high-quality image playback.

Furthermore, in the carrier color signal low-pass conversion recording method, crosstalk mixed into the reproduced carrier color signal can be removed without using a line correlation comb filter, and by using the line correlation comb filter, the color vertical It is possible to prevent directional spread and further improve the quality of the reproduced image.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the video signal recording and reproducing apparatus according to the present invention, FIG. 2(a) is a frequency spectrum diagram of the output color video signal of the first embodiment, and FIG. 2(b)
is the frequency spectrum diagram of the luminance signal separated from this output color video signal by the frame correlation comb filter, the third
The figure is a block diagram showing a second embodiment of the video signal recording and reproducing apparatus according to the present invention, and FIG. )
is a frequency spectrum diagram of a carrier color signal separated from this output color video signal by a frame correlation comb filter, and FIG. 5 is a block diagram showing a recording system of a third embodiment of the video signal recording and reproducing apparatus according to the present invention. FIG. 6 is a block diagram showing the reproduction system, and FIG. 7 is a diagram showing the phase of crosstalk in the third embodiment. FIG. 8 is a block diagram showing an example of a frame correlation noise reducer, and FIG. 9 is a block diagram showing an example of a frame correlation noise reducer. FIG. 10 is an explanatory diagram showing the action of the line correlation comb filter; FIG. 11 is an explanatory diagram showing the action of the frame correlation comb filter; Figure (a) is a frequency spectrum diagram of the output color video signal of a VTR using the conventional carrier color signal low-pass conversion recording method, and Figure (b) is the luminance signal separated from this output color video signal by a frame correlation comb filter. FIG. 6... Luminance signal reproducing circuit, 7... Color signal reproducing circuit, 13... Time axis fluctuation correction device, 1
6...C-shaped frame correlation comb filter, 1
8... Color video signal output terminal, 23...
...Y-shaped frame correlation comb filter, 24...
... Color video signal input terminal, 28 ... Comb filter, 29 ... Luminance signal recording circuit, 3
2... Color signal recording circuit, 33... Converter, 39... Selector, 41...
Initial value setting circuit, 42...Ring counter, 4
3...Low pass filter, 44...Converter, 51...Selector, 52...
・Initial value setting circuit, 53...Ring counter, 5
4...Phase difference detection circuit, 57...C-type line correlation comb filter, 58...Switch. Fig. 1 Fig. 2 Fig. Fig. Fig. Fig. Fig. Fig. 10 Fig.

Claims (1)

[Scope of Claims] 1. In a video signal recording and reproducing apparatus that records and processes an input color video signal by separating it into a luminance signal and a carrier signal, and multiplexes the signals for recording and reproducing, time-axis fluctuations of the reproduced luminance signal a luminance signal correction means for correcting the time axis fluctuation of the reproduced carrier color signal; and a color signal corrector for extracting a component that is inverted for each frame of the reproduced carrier color signal from the color signal corrector. 1. A video signal recording and reproducing device comprising: a filter means. 2. In claim 1, the color signal correction means includes a decoder for demodulating the reproduced carrier color signal into two baseband color difference signals, a memory for writing and reading out the color difference signals, and a memory for reading out and writing the color difference signals. A video signal recording and reproducing apparatus comprising: an encoder that generates a carrier color signal from the color difference signal and supplies it to the color signal filter means. 3. The video signal recording and reproducing apparatus according to claim 1, further comprising a luminance signal filter means for extracting a component that is not inverted for each frame of the reproduced luminance signal from the luminance signal correction means. 4. In claim 3, the luminance signal filter means:
A video signal recording and reproducing device characterized in that it is a frame correlation comb filter. 5. In claim 3, the luminance signal filter means:
A video signal recording and reproducing device characterized in that it is a cyclic noise reducer having a frame memory as a delay means. 6. The video signal recording and reproducing apparatus according to claim 1, 2, 3, 4 or 5, wherein the color signal filter means is a frame correlation comb filter. 7. The video signal recording and reproducing apparatus according to claim 1, 2, 3, 4 or 5, wherein the color signal filter means is a cyclic noise reducer having a frame memory as a delay means. 8. A signal separation circuit that separates an input color video signal into a luminance signal and a carrier color signal, a luminance signal recording circuit that frequency-modulates the luminance signal, and a luminance signal recording circuit that frequency-modulates the carrier color signal so that the phase is 1H (however, 1H changes every 1 horizontal period), and 1
and a color signal recording circuit that generates a low frequency conversion carrier color signal whose phase change direction is reversed for each field, and multiplexes the frequency modulated luminance signal and the low frequency conversion carrier color signal, records and reproduces the multiplexed signal, and reproduces the signal. a luminance signal reproducing circuit that frequency-demodulates a frequency-modulated luminance signal; and a color signal reproducing circuit that has high-frequency conversion means that converts the reproduced low-frequency converted carrier color signal into a carrier color signal of the original frequency by removing the phase change. In the video signal recording and reproducing apparatus, the color signal recording circuit includes a phase conversion means for varying the phase difference between the first and second fields by 180 degrees for each frame of the low-frequency conversion carrier color signal; The color signal reproducing circuit is provided with a phase restoring means for equalizing the phase difference in the reproduced low-pass conversion carrier color signal, and the luminance signal is further configured to correct a time axis fluctuation of the reproduced luminance signal from the luminance signal reproduction circuit. a signal correction means; a color signal correction means for correcting time axis fluctuations of the reproduced carrier color signal from the color signal reproduction circuit;
A video signal recording and reproducing apparatus comprising: color signal filter means for extracting a component that is inverted for each frame of the reproduced conveyance color signal from the color signal correction means. 9. Claim 8, wherein the color signal reproducing circuit is configured to determine whether or not the phase difference between the first and second fields changes by 180° for each frame in the reproduced low frequency conversion carrier signal. a phase difference detection means, a line correlation comb filter for extracting a component that is inverted every 1H of the reproduced carrier color signal from the high frequency conversion means, and a a switch for selecting either the reproduced carrier color signal from the range converting means or the output carrier color signal of the line correlation comb filter and supplying the selected one to the color signal correcting means; Only when the phase difference between the first and second fields of the color signal changes by 180 degrees for each frame, the switch selects the reproduced carrier color signal from the high frequency conversion means, and changes the phase of the color signal. A video signal recording and reproducing device characterized in that a restoring means operates. 10. The video signal recording and reproducing apparatus according to claim 8, wherein the signal separation means is a frame correlation comb filter.