JP2502499B2 - Video signal processing device - Google Patents

Description

Description: INDUSTRIAL APPLICABILITY The present invention can be applied to a recording / reproducing device such as a VTR and a video signal transmitting device, and is effective for obtaining good high frequency characteristics of a luminance signal and characteristics of a color signal. Is.

2. Description of the Related Art Currently, VTRs used for broadcasting are mainly tapes having a tape width of 1 inch and 2 inches, and a video signal recording method thereof is to directly frequency-modulate a composite video signal. During this recording / reproducing process, time-axis fluctuation occurs due to uneven rotation of the head, uneven running of the tape and the like. This fluctuation is corrected by a time axis corrector (TBC) during reproduction using a horizontal synchronizing signal and a burst signal in the reproduced video signal. However, in this system, in the case of the NTSC system, the chrominance signal is quadrature two-phase modulated with a 3.58 MHz subcarrier and is superimposed on the luminance signal. The characteristic noise is not sufficiently reduced, and the color subcarrier has a phase fluctuation corresponding to the residual jitter of TBC, which becomes phase noise and the convergence of the color vector is not sufficient.

From this point of view, as described in Japanese Patent Application No. 59-163155, as one recording method for improving the S / N in the amplitude and phase direction of the color signal and improving the convergence, two components of the color signal are also There is a method of modulating and recording, and correcting the time axis at the time of reproduction, and then modulating (encoding) with a reference subcarrier and adding to the luminance signal in order to form a composite video signal. According to this method, since the color signal (component signal) is also FM recorded in the baseband, it is reproduced well with S / N and encoded with the reference subcarrier, so there is no phase noise and it is good. It is possible to obtain various reproduced color signals.

An example of this system will be described with reference to FIG. In FIG. 3, reference numerals 1, 2, and 3 are luminance signal (Y), RY signal, and BY signal input terminals, 25 is a synchronizing signal generator, 5 is a time axis compressor, and 4 and 6 are frequencies. Modulator, 7 and 8 are heads, 9 and 10 are frequency demodulators, 11 and 12 are TBC, 14 is a reference signal input terminal, 15 is a sync generator, 16 is an encoder, 18, 19, 20, and 21 are Y, respectively. , RY, BY signals and composite video signal output terminals. The Y signal applied to the terminal 1 is modulated by the frequency modulator 4 and recorded on the tape by the hud 7. On the other hand, terminal 2,
The two color signal components RY signal and BY signal applied to 3 are added to the RY signal by the adder 26 with the sync signal generated by the sync signal generator 25 from the horizontal sync signal in the Y signal. Added,
With the time axis compressor 5, the time axis compression is halved for each line, and ▲ ▼ ・ ▲ ▼ ・ ▲ ▼ ・ ▲ ▼
.. is converted into one signal (.delta. Represents an RY signal compressed into 1/2 line), modulated by the frequency modulator 6, and recorded on the tape by the head 8. The luminance signal and the chrominance signal form separate tracks by the head 7 and the head 8 and are recorded on the tape. During reproduction, the Y signal reproduced by the head 7 is demodulated by the frequency demodulator 9 and then corrected in time axis by the TBC 11. The color signal reproduced by the head 8 is demodulated by the frequency demodulator 10 and then corrected on the time axis by the TBC 12 and expanded to the original time axis. The TBCs 11 and 12 write signals to the memory by the write clock created from the horizontal sync signal in the reproduced and demodulated signals, and read clocks 22, 23 created by the sync generator 15 from the reference signal applied to the terminal 14. By reading the signal from the memory, the time axis correction and extension motion are performed. Further, here, the sync signal is removed, and the reference sync signal 24 created by the sync generator 15 is added to the Y signal.
Add by 13. In this way, the sync signal without noise is replaced, and the reproduced Y, RY, BY signals are obtained at the terminals 18, 19, 20. On the other hand, the output R-Y, B-Y signals of the TBC 12 are encoded by the encoder 16 by the reference subcarrier 27 created by the sync generator 15, added by the adder 17 with the Y signal, and reproduced at the terminal 21 by the composite video signal. Is obtained.

In this method, since Y, RY, BY signals are input,
When recording a composite video signal, use a Y, R-
After separating into Y and BY, they are led to the input terminals 1, 2 and 3. At the time of this separation, a comb filter using line correlation is generally used in order to widen the band of the luminance signal and the color signal.

Problems to be Solved by the Invention In separation of a luminance signal and a chrominance signal using a comb filter, a chrominance signal is mixed with a luminance signal and a chrominance signal is mixed with a luminance signal in a portion having no correlation. Color signal components RY, B-
The Y signal is recorded / reproduced, then modulated again by the encoder to be a carrier color signal, and then added to the reproduced luminance signal, but the carrier color before being demodulated into RY and BY during modulation. When modulated with a carrier wave having the same phase as the signal and added together with the same phase as the color signal mixed in the luminance signal, the components mixed together are restored to the original state. If done in this way, the high frequency component of the luminance signal is also mixed with the color signal and transmitted, and again added to the signal transmitted in the luminance signal band in the correct phase,
A good signal can be obtained. In addition, the color signal is also restored to the original state, and is obtained as a good signal with no color shift or change in saturation. However, in general, the phase of the color subcarrier of the output signal of the VTR is freely adjusted with respect to the phase of the color subcarrier of the reference signal from the input terminal 14 at the TBC in order to adjust the delay with other video signal systems. Made to change. Also, the phase of the color subcarrier of the input composite video signal at the time of recording is the same in four fields in the case of the NTSC signal, but the phase relationship between the reproduced signal and the reference input signal is often only the odd-even field discrimination. . In such a case, RY,
The phase of the color subcarrier modulated by the BY signal and the phase of the original composite video signal are not fixed. When modulated with the opposite phase, the color of the uncorrelated part disappears, and the high frequency band of the luminance signal disappears. Further, if the phases are not perfectly matched, the high frequency band of the luminance signal and the distortion of the color signal appear.

This phenomenon causes some difference in quantity even when a low-pass filter or a bandpass filter is used instead of a comb filter for separating a luminance signal and a chrominance signal.

The present invention provides a means for removing such high band of luminance signal and distortion of chrominance signal to obtain a good reproduction or transmission signal.

Means for Solving the Problems In order to solve the above problems, the present invention provides a color subcarrier representing the phase itself of a color subcarrier of an input composite video signal together with either a luminance signal or two chrominance signal components. And recording or transmitting a first signal having the same frequency as, and comparing the phase of the color subcarrier modulated (encoded) with the reproduced or transmitted two color signal components and the phase of the first signal. , A means for controlling the phase relationship between these signals so that the phase of the color subcarrier contained in the input composite video signal and the phase of the second signal become the same or closest to each other.

As the first signal transmitted with either the luminance signal or the two chrominance signal components, the VIR signal added to the vertical blanking of the input composite video signal may be used as it is, or a new luminance signal or A signal having a constant phase (the frequency may be the same as or synchronized with the color subcarrier) may be added to the vertical blanking of the two color signal components, or a burst signal in the input composite video signal. May be used as it is, or a new burst signal (the frequency may be the same as or synchronized with the burst signal) may be used by replacing it with either the luminance signal or the two chrominance signal components. The means for controlling the color subcarrier contained in the reproduced or transmitted input composite video signal and the phase of the color subcarrier modulated by the two color signal components so as to be in phase or close to each other are controlled by the TBC. A method of controlling the timing of reading, a method of controlling the timing of writing to the TBC, a method of controlling the amount of delay of a reproduced or transmitted luminance signal and two color signals by a variable delay line,
If the phase of the color subcarrier of the output composite video signal may be arbitrary, there is a method of controlling the phase of the color subcarrier modulated by the two color signal components.

Action By taking the above means, the reproduced or transmitted signal that is re-encoded and returned to the composite video signal has the same high frequency range as the luminance signal or the phase of the chrominance signal as the original input signal or distortion. Since it is the minimum, the resolution is good even in a place where there is no correlation, and a high-quality signal with no or little color shift is obtained.

EXAMPLE The present invention will be described with reference to the block diagram of one example of the present invention shown in FIG. In FIG. 1, the same numbers as those in FIG. 3 represent the same items and perform the same operations. 28 is a composite video signal input terminal, 29 is a reference phase signal generator, 36 is a decoder, 30 is an adder, 31 is a video signal phase adjustment signal input terminal, 32 is a color subcarrier phase adjustment signal input terminal, and 33 is a reference phase. Signal extractor,
Reference numeral 34 is a phase comparator, and 35 is a phase shifter. The composite video signal applied to the terminal 28 is separated by the decoder 36 into Y, RY and BY signals. At this time, in the portion having no correlation, the color signal component remains in the Y signal and the Y signal component remains in the RY and BY signals. The recording process of the RY and BY signals is the same as in FIG. On the other hand, the Y signal is a reference phase signal (same frequency as the color subcarrier or synchronized with this) generated by the reference phase signal generator 29 from the color subcarrier (created from burst signal, VIR signal, etc.) in the input composite video signal. Signal, the same frequency as the color subcarrier in the following description [3.58 MHz for NTSC signals
z)) is added to a predetermined position (vertical blanking, burst signal position, etc., treated as one line in vertical blanking in the following description) by the adder 30,
It is recorded on the tape in the same manner as the figure. At the time of reproduction, the reproduction Y signal is obtained at the output of TBC11 and the reproduction RY, BY signals are obtained at the output of TBC12 in the same manner as in FIG.
The -Y and BY signals are obtained at the terminal 21 as the reproduced composite video signal.

Here, the color subcarrier 27 created by the sync generator 15 is synchronized with the signal when the signal is applied to the reference signal input terminal 14, and is free-running when the signal is not applied. Further, the phase relationship with the input signal of the terminal 14 can be arbitrarily adjusted by the signal from the color subcarrier phase adjustment signal input terminal 32. Furthermore, TB is bypassed when the phase shifter 35 is bypassed.
The read signals (clock and horizontal / vertical reference signals) 22AB, 23AB of C11, 12 are arbitrarily moved by the signal from the video signal phase adjustment signal input terminal and output video signals (Y, R-
The phase of Y, BY and the composite video signal) is changed. Therefore, in the example of FIG. 3, the phase of the TBC output signal and the color subcarrier 2
The phase relationship of 7 is not fixed, and the above-mentioned problem occurs.
In addition, the following inconvenience occurs in a device having a simple configuration in which the phase of the output video signal and the phase of the color subcarrier are not varied. That is, the VTR having the configuration shown in FIGS. 1 and 3 is
In order to obtain continuity of the sync signal at the time of editing, servo control is performed so that the reference signal applied to the terminal 14 or the internal sync signal of the sync generator coincides with the odd-even field of the signal reproduced from the tape. However, in the case of the NTSC signal, the relationship between the phase of the color subcarrier and the field is the same in four fields. That is, the first, third or second, fourth
In the field, the sync signals are the same, but the color subcarriers are inverted. In the servo control described above, the output color subcarrier 27 of the sync generator 15 and the first, third, second, and fourth fields of the signal reproduced from the tape can be distinguished, but the first and third fields can be distinguished. Also, the second and fourth fields cannot be distinguished. Therefore, even if the reproduction signal and the phase of the color subcarrier are internally matched in the reproduction signal in one state, the phase becomes opposite in the reproduction in the opposite state, which is the worst state. This can be solved by performing servo control that can distinguish the first to fourth fields (known color frame servo), but the circuit becomes complicated,
It has the drawback that the pull-in time during editing becomes long. Further, even if this is done, it is invalid for the device controlling the terminals 31 and 32.

From the above points, in the present invention, as shown in the embodiment of FIG. 1, the reference phase signal added at the time of recording is extracted by the reference phase signal extractor 33 from the output Y signal of the TBC 11, and the output of the sync generator 15 is output. Reference color subcarrier 27 and phase comparator 34
The phases are compared with each other, the error signal is led to the phase shifter 35, and the TBC read signals 22A and 23B output from the sync generator 15 are compared.
The phase is controlled and the output signals 22B and 23B are used to read the Y, RY and BY signals from the TBCs 11 and 12. In this way, TB
The timing of reading the signal from C is controlled, and the output of TBC is always the Y, RY, BY signal with the residual color subcarrier in the input video signal of the same phase as or closest to the color subcarrier 27. And a good composite video signal is obtained at the terminal 21.

FIG. 2 shows another embodiment of the present invention (reproduction system only).
Will be described. This example is an example in which the color subcarrier synchronized with the output video signal is received from the outside (external TBC or the like) without using the TBC and modulation is performed. In FIG. 2, the third
The same reference numerals as those in FIG. 1 and FIG. 1 represent the same components and operate in the same manner. 37 is a sync signal separator, 38 is a sync signal remover, 39 is a time axis expander, 40 is a delay device, 41 and 42 are variable delay devices, and 43 is a color subcarrier input terminal. The reproduced and demodulated Y signal has its sync signal removed by the sync signal remover 38 and is guided to the variable delay unit 41. On the other hand, the compressed color signal which has been reproduced and demodulated is expanded by the time axis expander 39, returned to the RY and BY signals, and the sync signal added to the RY signal is removed.
It is led to the variable delay device 42. The reference phase signal is extracted from the output signal of the variable delay unit 41 by the reference phase signal extractor 33, guided to the phase comparator 34, and compared in phase with the color subcarrier input from the terminal 43. To the terminal 43, the color subcarrier generated from the output Y signal of the terminal 18 or the synchronizing signal in the output composite video signal of the terminal 21 is applied. By controlling the delay amount of the variable delay units 41 and 42 by the output error signal of the phase comparator 34, Y, R including the residual chrominance carrier whose phase matches or is closest to the chrominance subcarrier at its output, The -Y and BY signals are obtained, and the same effect as in the case of FIG. 1 can be obtained.
The sync signal separated by the sync signal separator 37 is matched in timing with the standard video signal by the fixed delay device 40, added again to the Y signal by the adder 13, and continuously connected to the terminals 18 and 21. A signal having the synchronized signal is obtained.

In addition to the above two embodiments, it is possible to add the reference phase signal and control the phase relationship between the reproduction signal and the color subcarrier by the various methods described in the means for solving the problem.

In the above embodiment, the two color signal components are RY.
However, I, Q signals or signals of any other axes may be used. The method of recording the two color signal components is not limited to the time base compression, and any method such as frequency modulation and multiplexing may be used. Further, a method of recording the luminance signal and the two color signal components on the time axis into one signal and recording with a pair of heads, a method of recording the two color signal components line-sequentially (two pairs of heads or one pair of heads) It is also effective for various methods such as head). Further, it goes without saying that the present invention can be used not only for recording / reproducing video signals but also for all processing of video signals such as transmission.

As another method, as a reference phase signal, a color frame (discrimination of the first, second, third and fourth fields) is detected from the input composite video signal and superimposed as a pulse signal, and the reference color subcarrier on the reproduction side There is also a method to control the delay amount of the playback signal so that it matches the color frame of, but in this method, the phase of the sync signal and color subcarrier of the input composite video signal is not completely in accordance with the standard, and there is a slight deviation. If so, the color subcarrier at the time of encoding does not match the residual color subcarrier of the video signal. Also, the phase of the output video signal cannot be controlled by external control.

As described above, according to the present invention, when the composite video signal is separated into the luminance signal and the two color signal components, and the composite video signal is obtained again after processing such as recording / reproduction or transmission, the high frequency band of the luminance signal is increased. It is possible to obtain a good signal by eliminating or minimizing the distortion of the color signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG. 3 is a block diagram of a conventional video signal recording / reproducing apparatus. 36 …… decoder, 29 …… reference phase signal generator, 30 …… adder, 16 …… encoder, 33 …… reference phase signal extractor,
34: Phase comparator, 35: Phase shifter, 41, 42: Variable delay device.

Continuation of the front page (56) Reference JP-A-59-185494 (JP, A) JP-A-58-179075 (JP, A) JP-A-51-25022 (JP, A) JP-A-57-111196 (JP , A) JP-A-57-121391 (JP, A)

Claims (5)

(57) [Claims] 1. A composite video signal is separated into a luminance signal and two color signal components, and after recording / reproduction or transmission, the two color signal components are modulated again and superimposed on the luminance signal to obtain a composite video signal. At this time, the first signal having the same frequency as the color subcarrier representing the phase itself of the color subcarrier in the original composite video signal together with at least one of the luminance signal to be recorded or transmitted and the two color signal components. The phase of the recorded or transmitted and reproduced first signal is compared with the phase of the reproduced or transmitted color subcarrier (second signal) modulated by the two color signal components, and the error signal And a phase relationship between the phase of the second signal, the reproduced or transmitted luminance signal, and the two color signal components in the direction in which the phase of the color subcarrier in the video signal and the phase of the second signal coincide with each other. Is characterized by controlling Video signal processing apparatus. 2. The video signal processing device according to claim 1, wherein the first signal is recorded or transmitted by being superimposed on a luminance signal separated from the composite video signal. 3. A phase of a color subcarrier modulated by the reproduced or transmitted two color signal components by controlling the amount of delay of the reproduced or transmitted luminance signal and the two color signal components, The video signal processing device according to claim (1), characterized in that the phase relationship between the reproduced or transmitted luminance signal and the two color signal components is controlled. 4. A reproduced or transmitted luminance signal and two chrominance signal components are temporarily stored in a storage device, and when read out, the delay amount is controlled so that the reproduced or transmitted two chrominance signal components The video signal processing device according to claim (3), characterized in that the phase relationship between the modulated color sub-carrier and the reproduced or transmitted luminance signal or two color signal components is controlled. 5. When a reproduced or transmitted luminance signal and two chrominance signal components are temporarily stored in a storage device and read out to eliminate time-axis fluctuations of these signals, by controlling the delay amount thereof, A phase relationship between a color subcarrier modulated by the reproduced or transmitted two chrominance signal components and a phase relationship between the reproduced or transmitted luminance signal and two chrominance signal components is controlled. The video signal processing device according to item (4).