JPS61283299A - Video signal processor - Google Patents

Abstract

PURPOSE:To apply a reference signal to a VIR signal used in a broad-casting station at present and to adjust color phase or color saturation by carrying a chrominance subcarrier as a correct reference signal in an encoder. CONSTITUTION:Receiving blanking signal from a sync generator 15, an index information overlapped in a recording time is blanked at a blanking circuit 37. Also, a reference chrominance subcarrier 27 is overlapped on a compound video signal as the reference signal (index signal) at one line in a blanking period V at a reference phase signal generator 39 by an adder 40 and is outputted from an output terminal 21. Thereby, by the uncertainty of the VIR signal, a problem that the color phase or the color saturation is not exactly transmitted to other equipments can be resolved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a video signal processing device that can be used in recording and reproducing devices such as VTRs and video signal transmission devices, and is effective in obtaining stable color signal characteristics. .

2. Description of the Related Art Currently, VTRs used for broadcasting are mainly tape widths of 1 inch or 2 inches, and their video signal recording method is to directly frequency modulate the composite video signal. During this recording/reproducing process, time axis fluctuations occur due to uneven rotation of the head, uneven running of the tape, and the like.

This variation is corrected by a time base corrector (TBC) during playback using a horizontal synchronization signal and a burst signal in the playback video signal. However, in this method, the color signal is NT
In the case of the SC method, it is quadrature two-phase modulated with a subcarrier of ij 3.58 MHz and superimposed on the luminance signal, so when it is frequency modulated, it is separated from the modulation carrier, so
Noise reduction, which is a characteristic of FM, is not sufficient, and TB
The color subcarrier has a phase fluctuation corresponding to the residual jitter of C, which becomes phase noise, and the degree of convergence of the color vector is not sufficient.

From this point of view, as shown in Japanese Patent Application No. 59-163165, as a recording method that improves the amplitude and 3/N of the phase direction of the color signal and improves the degree of convergence, a composite video signal is decoded and the luminance is Separate the signal and color signal, frequency modulate each signal, record it, correct the time axis during playback, and then modulate it with a reference subcarrier (
There is a method of encoding the image (encoding) and adding it to the luminance signal. According to this method, the color signal (component signal) is also recorded as FM in the baseband, so it can be reproduced with good S/N, and since it is encoded with the standard subcarrier, it does not have phase noise and has good quality. It is possible to obtain a reproduced color signal.

However, the disadvantage of this method is that when recording a composite video signal, the decoder uses Y, R-Y, B-
Record after separating into Y. At the time of separation, a comb filter using line correlation is generally used to widen the band of the luminance signal 9 electric signal.

Luminance signal (Y) using comb filter 9 electric signal (C)
In this separation, the color signal is mixed into the luminance signal and the luminance signal is mixed into the color signal in uncorrelated parts. After the color signal components R-Y and B-Y signals are recorded and reproduced, they are modulated again by an encoder and made into a carrier color signal, which is then added to the reproduced luminance signal. When it is modulated with a carrier wave that has the same phase as the carrier color signal before being demodulated to Y, and is added with the same phase as the color signal mixed into the luminance signal,
The mixed components are restored to their original state.

If this is done, the high-frequency components of the luminance signal will also be transmitted mixed with the chrominance signal, and will be added to the signal transmitted in the luminance signal band again in the correct phase, making it possible to obtain a good signal.

Further, the color signal is also restored to its original state, and a good signal without color shift or change in saturation is obtained. However,
Generally, the phase of the color subcarrier of the output signal of a VTR can be freely changed in the TBC with respect to the phase of the color subcarrier of the reference signal from the input terminal in order to adjust the delay with other video signal systems. be accomplished. Further, the phase of the color subcarrier of the input composite video signal during recording is one in four fields in the case of a NTSC signal, but in many cases, the phase relationship between the reproduced signal and the reference input signal is determined only by odd-even fields. In such a case, R-! , the phase of the color subcarrier modulated by the B-Y signal and the phase of the original composite video signal are not determined. When modulated with a phase opposite to the original, colors in uncorrelated parts disappear, and the high range of the luminance signal disappears.

Furthermore, if the phases do not match completely, distortion will appear in the high frequency range of the luminance signal and the color signal.

This phenomenon occurs even if a low-pass filter or a bandpass filter is used instead of using a comb filter to separate the luminance signal and the electric signal, albeit to a different extent.

Further, in the future, when component recording type VTRs become mainstream for broadcasting, the number of times of encoding and decoding during various video signal processing will increase, and the above problem will become an important issue for the component recording type. Therefore, in Japanese Patent Application No. 80-19451, the present inventor proposed a method for solving the above problem by always matching the phases of the color subcarriers in the decoder and encoder.

The above solution method records or transmits the color subcarrier of the input composite video signal together with the Y/C separated luminance signal as index information, and modulates (encodes) the color subcarrier with the two reproduced or transmitted color signal components. The phase relationship between these signals is controlled so that the phase of the carrier wave and the phase of the inch sox information match or become as close as possible. Of course, V is already superimposed on the input composite video signal.
Phase control can also be performed using the TR signal.

FIG. 2 shows a circuit diagram explaining the above solution.

In the figure, 28 is a composite video signal input terminal, 29 is a reference phase signal generator, 36 is a decoder, and 3o is an adder. At the decoder 3θ, the luminance signal Y1. RY signal 2. B
- The luminance signal 1 is generated from the reference phase signal (same as the color subcarrier) generated by the reference phase generator 29 from the input composite video signal medium color subcarrier (generated by burst signal, VIR signal, etc.). frequency) is added to a predetermined position (an appropriate line within V blacking) by an adder 30.

25 is a synchronization signal generator, 5 is a time base compressor, 4.6 is a frequency modulator, 7.8 is a head, 9, 101'j frequency demodulator, 11.12idTBC114 is a reference signal input terminal, 15 is a sync generator , 16 is an encoder, 1
8, 19, 20゜21 are Y, R-Y, B-Y respectively
This is a signal and composite video signal output terminal. The Y signal applied to the terminal 1 is modulated by a frequency modulator 4 and recorded on tape by a hella door. On the other hand, the two color signal components R-Y signal and B-Y signal applied to terminal 2.3 are
The synchronization signal generated by the synchronization signal generator 26 is added from the horizontal synchronization signal in the signal by the adder 26, and the synchronization signal is added to the time base compressor 6.
(represents the R-Y signal compressed in line by line), then modulated by the frequency modulator 6 and sent to the head 8.
recorded on tape. The brightness signal and color signal are sent to the head 7.
, head 8 form separate tracks and record them on the tape. During reproduction, the Y signal reproduced by the head 7 is demodulated by the frequency demodulator 9, and then the time axis is corrected by the TBCl 1. Further, the color signal reproduced by the head 8 is demodulated by the frequency demodulator 10, and then the time axis is corrected by TBCl2 and expanded to the original time axis.

TBCll and 12 write a signal to the memory using a write clock created from a horizontal synchronization signal in the reproduced and demodulated signal, and write a signal to the memory using a write clock created from a horizontal synchronization signal in the reproduced and demodulated signal, and write a signal to the memory using a reference signal created by a sync generator 15 from a reference signal applied to a terminal 14.
The readout block 22B passed through.

By reading the signal from the memory using 23B,
Performs time axis correction and expansion operations. In addition, the synchronization signal is removed here, and the Y signal includes the sync generator 1.
The reference synchronization signal 24 created by 5 is added by the adder 13. In this way, the noise-free synchronization signal is exchanged, and the reproduction Y, R is output to terminals 1B, 19, 20.
-Y, BY signals are obtained. On the other hand, the output R-Y and B-Y signals of TBCl2 are encoded by the encoder 16 using the reference color subcarrier 27 created by the sync generator 15, and then by the adder 17! When added to the signal, a reproduced composite video signal is obtained at the terminal 21.

31 is a video signal phase adjustment signal input terminal, 32 is a color subcarrier phase adjustment signal input terminal, 33 is a reference phase signal extractor, 34 is a phase comparator, and 35 is a phase shifter.

Here, the color subcarrier 2T generated by the sync generator 15 synchronizes with this signal when a signal is applied to the reference signal input terminal 14, and becomes free-running when no signal is applied. In addition, color subcarrier phase adjustment signal input terminal 3
The phase relationship with the input signal at the terminal 14 can be arbitrarily adjusted by the signal from the terminal 14. Further, in a state where the phase shifter 35 is bypassed, the readout signals (clock and horizontal and vertical reference signals) 22 and 235B of TBOll and 12 are arbitrarily shifted by the signal from the video signal phase adjustment signal input terminal. , to vary the phase of the output video signal (Y, RY, BY, and composite video signal).

Therefore, the phase relationship between the TBC output signal and the color subcarrier 27 is not determined, resulting in the above-mentioned problem. Further, even in a device having a simple configuration in which the phase of the output video signal or the phase of the color subcarrier is not varied, the following inconvenience occurs.

The VTR configured as shown in Figure 2 uses the reference signal applied to the terminal 14 or the internal synchronization signal of the sync generator and the odd-even signal reproduced from the tape in order to obtain continuity of the synchronization signal during editing. It is servo controlled to make the fields match 1. However, in the case of the NT3G signal, the relationship between the phase of the color subcarrier and the field is the same for four fields. That is, 1st. Third or second. In the fourth field, the synchronization signal is the same, but the color subcarrier is inverted. In the above servo control, the output color subcarrier 27 of the sync generator 16 and the first .
3rd field and 2nd field. Although the fourth field can be distinguished, the first and third fields and the second and fourth fields cannot be distinguished. Therefore, even if the reproduction signal is in one state and the phase of the color subcarrier is matched internally, when the reproduction signal is in the opposite state, the phases will be reversed, resulting in the worst condition. This problem can be solved by using servo control that can also distinguish between the first and second fields (
The known color frame servo) has disadvantages in that the circuit is complicated and the pull-in time during editing is long. Also,
Even if you do this, terminal 31. It is invalid for devices that are controlled from the terminal 32.

From the above points, as shown in FIG. 2, the reference phase signal added during recording is extracted from the output Y signal of TBCll by the reference phase signal extractor 33,
The phase comparator 34 compares the phase with the output reference color subcarrier 27 of the sync generator 15, and the error signal is guided to the phase shifter 35, which outputs the TBC readout signal 22, which is the output of the sync generator 15.
23 and output signals 22B and 23B.
From τBC11 and 12, Y, R-! , reads the B-Y signal. In this way, the readout timing of the signal from the TBC is controlled, and the output of the TBC always has the residual color subcarrier in the input video signal with the same or closest phase to the color subcarrier 27! , RY, and BY signals are obtained, and a good composite video signal is obtained at the terminal 21.

Problems to be Solved by the Invention However, if the composite video signal output from the terminal 21 is connected to other video signal processing equipment or a VTR, and the VTR shown in FIG. 2 outputs normal videos, etc. other than test patterns. At times, subsequent video signal processing equipment cannot obtain accurate standards such as color phase and color saturation.

In this sense, in the current broadcasting station systems that use 1-inch VTRs, etc., the VIR signal is superimposed on one line of the V blanking period of the video signal.

Since this VIR signal has information on only one line, conventional decoders cannot completely separate Y10, and naturally the terminal 2
The VER signal output from 1 becomes uncertain.

Furthermore, due to the configuration of the phase control system, it is conceivable that the index information section does not perform phase control, but instead detects a phase error with the phase comparator 34 and applies phase control to other video signal lines. If the VIR signal is used as the index information, the color phase of the index information becomes completely meaningless.

Means for Solving the Problems The present invention provides an encoder that processes a luminance signal and two color difference signals and obtains a composite video signal from the luminance signal and the two color difference signals as an output signal, and a map planning period for the composite video signal. The video signal processing apparatus is characterized in that it includes means for superimposing a reference signal having the same frequency as the color subcarrier signal in the encoder on an appropriate line of the encoder.

Operation In this way, by loading the color subcarrier as a correct reference signal in the encoder, it can be used as a VIR signal, which is no longer used in current broadcasting stations, and the color phase and color saturation can be adjusted. Further, when a dubbing system using a VTR as shown in FIG. 2 is configured, since index information has already been added by the encoder, there is no need to add a new index by the decoder.

Embodiment FIG. 1 shows an embodiment of the present invention and will be described. FIG. 1 has almost the same configuration as FIG. 2, and the same numbers perform the same operations.

In the figure, upon receiving the 7 linking signal 38i from the sync generator 15, the blanking circuit 37 performs blanking δ of the index information that was superimposed at the time of recording. Further, one reference color subcarrier 27 is transmitted to the reference phase signal generator 3.
At step 9, the signal is superimposed on the composite video signal by the adder 4o as a reference signal (index signal) on one line of the V blanking period, and is outputted from the output terminal 21.

In the above embodiment, the explanation was limited to a VTR, but it is also applicable to devices that perform other component processing.

In addition to the index superimposition method shown in the embodiment of FIG.
Component color difference signal at the 19-m or 20-m position immediately before the encoder input in the same figure (R-th, B-th)
Alternatively, it can be constructed by superimposing pulses on a suitable line during the V blanking period. That is, the pulses are modulated and obtained in a reference phase signal generator 39. The signal is the same as the reference signal (index signal).

Effects of the Invention According to the present invention, the problem of component processing device v
This solves the problem that the color phase, color saturation, etc. are not correctly transmitted to other equipment due to the uncertainty of the engineering R signal, and furthermore, the index in the decoder of the subsequent VTR in the dubbing system can be corrected. Additional recirculation reference phase signal generator 29. Adder 30) is also not required.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of a video signal processing device according to the present invention, and FIG. 2 is a block diagram of the previously proposed video signal processing device. 1... Luminance signal, 2,3... Color difference signal, 21... Composite video signal, 16... Encoder, 27... Color Subcarrier, 39...
...Reference signal (reference phase signal generator). Name of agent: Patent attorney Toshio Nakao and 1 other person
1 of

Claims (2)

[Claims] (1) An encoder that processes a luminance signal and two color difference signals and obtains a composite video signal from the luminance signal and the two color difference signals as an output signal; A video signal processing device comprising means for superimposing a reference signal of the same frequency as a color subcarrier signal in an encoder. (2) The video signal processing device according to claim 1, wherein a reference signal is superimposed on a V blanking period of at least one of the color difference signals.