JPH0430238B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention provides time-division multiplexing of each component signal such as a luminance signal Y and each color difference signal B-Y, R-Y constituting a color video signal in a time-series manner. The present invention relates to a color video signal processing circuit for transmitting signals, and is applied, for example, to a magnetic recording/reproducing device that magnetically records each component signal on one recording track and reproduces a color video signal.

[Background technology and its problems]

Generally, in a signal transmission system that handles high-resolution color video signals with a wide frequency band, the luminance signal Y and each color difference signal B-
By providing a transmission channel for each component signal such as Y, RY, etc., it is possible to transmit color video signals with a wide frequency band. For example, it has been known in the past for video tape recorders to provide multiple recording tracks for each component signal and record the luminance signal Y and each color difference signal B-Y, R-Y in multiple channels. .

However, in a conventional video tape recorder that records each component signal of a color video signal in multiple channels, the number of recording tracks increases correspondingly to the increase in the number of channels, so that the recording density decreases. Furthermore, since there is no correlation between information recorded on adjacent recording tracks, interference due to crosstalk becomes a problem, and it is difficult to obtain a high-quality reproduction signal, especially in the case of variable speed reproduction.

Another possible method is to handle the color video signal by dividing it into frequency bands, but this method has problems such as interference occurring between each band.

[Purpose of the invention]

Therefore, in view of the above-mentioned problems in multi-channel recording video tape recorders, the present invention makes it possible to time-division multiplex each component signal that makes up a color video signal and handle it together with a synchronization signal as a single channel signal. The object of the present invention is to provide a color video signal processing circuit with a novel configuration.

[Summary of the invention]

In order to achieve the above-mentioned object, the color video signal processing circuit according to the present invention compresses the luminance signal and the first and second color signals constituting the color video signal in the time axis, and each of the time-axis compressed signals In a color video signal processing circuit that time-division multiplexes the signals, converts them into time-series signals, and outputs the signals, one horizontal scanning period is divided into three sections, first to third, and blanking is performed at predetermined intervals within each section. In addition to providing intervals, a synchronization signal is inserted into each blanking interval, the time-axis compressed luminance signal is placed in each interval of the one horizontal scanning period, and the time-axis compressed first color signal is into the second section, the time-axis compressed second color signal into the third section,
The present invention is characterized in that time-series signals are arranged in combination with the above luminance signals and time-division multiplexed to output the time-series signals.

〔Example〕

Hereinafter, one embodiment of the color video signal processing circuit according to the present invention will be described in detail with reference to the drawings.

An embodiment in which the present invention is applied to a video tape recorder is shown in FIGS. 1 to 4.

In FIG. 1 showing the recording system signal processing circuit of this embodiment, a composite color video signal _Sio is supplied to a signal input terminal 1, and this composite color video signal _Sio is sent from the signal input terminal 1 to a color decoder 2. Supplied. The color decoder 2 decodes the composite color video signal S _io and outputs each component signal making up the composite color video signal S _io , such as a luminance signal Y and each color difference signal B-Y, RY. do.

Luminance signal Y obtained by the color decoder 2 above
is supplied to the first time-base compression circuit 4 via the first analog-to-digital A/D converter 3. The first time-base compression circuit 4 subjects the luminance signal Y digitized by the first A/D converter 3 to time-base compression processing.

Further, one color difference signal B-Y obtained by the color decoder 2 is sent to a second time-base compression circuit 6 via a second analog-to-digital A/D converter 5.
and is time-base compressed by the second time-base compression circuit 6. Similarly, the other color difference signal R-Y obtained by the color decoder 2 is supplied to the third time-base compression circuit 8 via the third analog-to-digital A/D converter 7 and subjected to time-base compression. Ru.

Note that the first to third A/D converters 3,
For example, component signals Y, BY, and RY may be directly supplied to signals 5 and 7 from the video camera 18. Furthermore, each of the above component signals is not limited to Y, B-Y, R-Y, but Y, I,
Furthermore, the composite color video signal composed of each component signal may be NTSC.
The color television system may be a system other than the standard color television system.

The luminance signal Y and each color difference signal B-Y, R-Y, which have been time-domain compressed by the first to third time-domain compression circuits 4, 6, and 8, are sent to the digital analog D /A converter 10. The data selector 9 receives the time-axis compressed luminance signal Y and each color difference signal B-
Y, RY are time-division multiplexed every 1H horizontal scanning period and converted into time-series signals. Luminance signal Y and each color difference signal B-Y, R converted into the above time-series signal
-Y is converted into an analog signal by the D/A converter 10, supplied to the FM modulator 11, and then sent to the recording amplifier 12.
to the magnetic tape 14 via the recording head 13.
FM modulation is recorded.

In the recording system signal processing circuit configured as described above, the first to third A/D converters 3, 5, 7
The luminance signal Y and each color difference signal B-Y, RY supplied from the color encoder 2 are sampled at the sampling frequency required for each signal band, and each of the above-mentioned signals Y,
Digitize B-Y, RY. Here, in terms of visual characteristics, the signal band of each color difference signal B-Y, RY may be about 1/4 of the band of the luminance signal Y.
Therefore, the sampling frequency for digitizing each of the color difference signals B-Y and RY can be set to 1/4 of the sampling frequency of the luminance signal.
In this example, the horizontal frequency _H is 800 times
A clock signal _CK1 having a clock frequency of 800 _H is supplied from the clock signal forming circuit 15 to the first A/D converter 3, and the luminance signal Y is digitized. Further, clock signals CK ₂ and CK ₃ having a clock frequency of 200 _H , which is 200 times the horizontal frequency _H , are sent from the clock signal forming circuit 15 to the second and third clock signals.
A/D converters 5 and 7 are supplied with each color difference signal B-
Y,RY is being digitized. Each A/D above
The digitalized component signals Y, B-Y, and R-Y obtained by the converters 3, 5, and 7 are synchronized signals with a horizontal scanning period T _H , and are shown in Fig. 2 A, B,
As shown in C, a blanking section BLK is provided at the beginning of each horizontal scanning period T _H.

Further, the first to third time axis compression circuits 4, 6, and 8 are each configured with a digital memory, and read out signals at a read clock frequency higher than the write clock frequency. Compression processing is now performed. In this embodiment, each of the above-mentioned time axis compression circuits 4, 6, and 8 includes each of the preceding stage A/D converters 3, 5,
7, each clock signal CK ₁ , CK ₂ , CK ₃ is supplied as a write clock signal from the clock signal forming circuit 15, and a read clock signal CK ₄ with a read frequency of 1200 _H is supplied to the clock signal forming circuit 15. It is supplied by 15. That is, in the first time axis compression circuit 4, the luminance signal Y digitized by the first A/D converter 3 is
is written with a write clock frequency of 800 _H by clock signal CK ₁ and read clock signal CK _4.
By reading out the luminance signal Y at a readout clock frequency of 1200 _H , the time axis of the luminance signal Y is compressed to 2/3 as shown in FIG. 2D. Further, in the second and third time axis compression circuits 6 and 8, each color difference signal B-Y, R-Y is written at a write clock frequency of 200 _H and read out at a read clock frequency of 1200 _H. By doing so, Figure 2 E, F
As shown in the figure, the time of each signal B-Y and RY is compressed to 1/6. Here, each of the signals Y, B-Y, and R-Y subjected to time axis compression in the first to third time axis compression circuits 4, 6, and 8 are read out at the same readout clock frequency of _1200H . Because there are
When converted into analog signals by the D/A converter 10, each signal has the same frequency band.

It goes without saying that the frequencies of the clock signals CK ₁ , CK ₂ , CK ₃ , and CK ₄ used in the time-base compression process may be changed to other frequencies.

Further, the data selector 9 selects each of the time-axis compressed component signals Y, B-Y,
When R-Y is being supplied, the synchronizing signal S _yoc is being supplied from the synchronizing signal generator 16, and according to the data select signal CK ₅ given by the clock signal forming circuit 15, [S _yoc ], [ Y], [S _yoc ], [B
-Y], [Y], [S _yoc ], [R-Y], and [Y] are selected in the order of time division multiplexing to form a time-series signal with the data arrangement shown in Figure 2G. do. That is, the data selector in this embodiment time-divides the luminance signal Y whose time axis has been compressed to 2/3 by the time axis compression process described above into three sections Y ₁ , Y ₂ , Y ₃ , and divides the luminance signal Y into three sections Y 1 , Y 2 , Y 3 , By combining each luminance signal Y ₂ , Y ₃ in the third section with each color difference signal B-Y, RY, each blanking portion BLK _Y of each component signal Y, B-Y, RY is , BLK _BY , BLK _RY is 1
A synchronizing signal S _yoc is inserted into the blanking sections BLK _Y , BLK _BY , BLK _RY so that the horizontal scanning period T _H is divided into three equal parts. In this embodiment, the time axis compression ratio of the luminance signal Y is for each color difference signal B-Y,R.
-Y, so the above luminance signal Y
Blanking part BLK _Y is other blanking part
Since it is wider than BLK _BY and BLK _RY , the blanking part BLK _Y of the above luminance signal Y is set during the horizontal scanning period.
By placing it at the beginning of T _H , the horizontal scanning period
The synchronization signal of T _H can be given by the blanking section BLK _Y. In addition, each blanking section above
Synchronization signal inserted into BLK _Y , BLK _BY , BLK _RY
S _yoc can be, for example, a synchronizing pulse with a 1/ _3TH cycle as shown in Figure 3A, with the pulse width _w1 at the beginning of _1TH being widened, or a synchronizing pulse with a _1TH cycle as shown in Figure 3B. For example, a 200 _H burst signal is superimposed on the synchronization pulse in the same phase at a 1/3 T _H period.

Each component signal Y, B-Y, R- on which the synchronization signal S _yoc converted into the above time-series signal is superimposed
Y can be transmitted as a one-channel signal, and is FM modulated and recorded on one track of the magnetic tape 14 using a single carrier.

As described above, the component signals Y, B-Y, and R-Y constituting the composite color video signal are compressed in time to the same frequency band, time-division multiplexed with the synchronizing signal S _yoc , and recorded on the magnetic tape 14 with FM modulation. In this embodiment, the reproduction system signal processing circuit can reproduce the composite color video signal by performing signal processing in a process reverse to that of the recording system signal processing circuit.

That is, in FIG. 4 showing the reproduction system signal processing circuit of this embodiment, the reproduction time-series signal reproduced by the reproduction head 21 from the magnetic tape 14 is supplied to the FM demodulator 23 via the reproduction amplifier 22 and is demultiplexed. After being adjusted, the analog-to-digital A/D converter 24
Digitized by.

Further, the reproduced time-series signal demodulated by the FM demodulator 23 is supplied to a synchronization separation circuit 34, where the synchronization signal S _yoc superimposed in the recording system described above is separated. Then, the synchronization signal S _yoc obtained by the synchronization separation circuit 34 is transmitted to the reproduction system clock signal forming circuit 3.
5, and in this reproduction system clock signal forming circuit 35, _the A/D
Each clock signal for driving the converter 24 etc. is formed.

The reproduced time series signal digitized by the A/D converter 24 is transferred to the data selector 25.
The component signals Y, B-Y, and R-Y are separated into the first to third time axis expansion circuits 2.
6, 28, 30. Here, the above A/
D converter 24 and each time axis expansion circuit 26, 2
8, 30 are each of the above-mentioned time axis compression circuits 4, 6, 8.
A clock signal having a write clock frequency of 1200 _H , which is the same as the read clock frequency of 1, is supplied from the regenerated clock signal forming circuit 35.

The luminance signal Y is read out from the first time axis expansion circuit 26 at a readout clock frequency of 800 _H , and returned to the normal time axis.
The digital-to-analog D/A converter 27 converts the signal into an analog signal. In addition, each color difference signal B-Y, R-Y
are the second and third time axis expansion circuits 28 and 28, respectively.
The signal is read out at a reading clock frequency of 30 to 200 _H , returned to the normal time axis, and converted into analog data by the second and third digital-to-analog D/A converters 29 and 31, respectively.

Furthermore, each of the D/A converters 27, 29, 31
Each component signal Y, B is converted into analog at
-Y, RY are supplied to the color encoder 32. The color encoder 32 forms a composite color video signal S _put from the component signals Y, BY, and RY, and outputs it from the signal output terminal 33 .

In addition, each component signal Y, B converted into an analog by each D/A converter 27, 29, 31
-Y, RY are supplied to the matrix circuit 37, and the three primary color signals R, B, G are supplied to the matrix circuit 37.
It is also possible to form a monitor television receiver 38 using the three primary color signals R, B, and G.

In the embodiment described above, the composite color video signal supplied to the signal input terminal 1 of the recording system signal processing circuit is
Each component signal Y, B that makes up V _io
-Y, RY can be transmitted as a single channel signal by compressing the time axis and converting it into a time series signal by time division multiplexing, and a single carrier is transmitted to the track of the magnetic tape 14. FM modulation can be recorded. Moreover, each component signal Y, B-Y, R-Y is time-division multiplexed.
By time-dividing the luminance signal Y into multiple parts and combining them with each color difference signal B-Y, R-Y, blanking intervals are provided to divide the horizontal scanning period T _H at equal intervals, and synchronization is achieved. Since the signal S _yoc is inserted, it is possible to reliably reproduce the data based on the synchronization signal S _yoc . Furthermore, since each component signal Y, B-Y, R-Y has the same band due to the above-described time axis compression, the magnetic tape 1
It is also possible to increase the recording density to 4. Also,
Adopting the so-called helical scan method, one recording track is recorded per recording track that is inclined with respect to the tape running direction.
Even when a field's worth of color video signals are recorded, since there is a correlation between the information on adjacent tracks, there is extremely little signal deterioration due to crosstalk components, and a high-quality reproduced signal can be obtained even during variable speed reproduction.

Note that the present invention is not limited to the above-described embodiments, and can be applied to various signal transmission systems other than magnetic recording and reproducing systems such as video tape recorders.
It may be other than various standard television systems such as NTSC system and PAL system. In addition, in the above embodiment, digital memory was used to perform time axis processing on each component signal, but CCD (Charge)
Time axis processing can also be performed using an analog shift register formed using a coupled device or the like.

〔Effect of the invention〕

As is clear from the description of the embodiments above, in the color video signal processing circuit according to the present invention, when a synchronization signal is superimposed on the luminance signal and the first and second color signals constituting the color video signal, one channel is processed. It can be transmitted as a series signal. In addition, since the synchronization signal is inserted into the blanking interval provided in each interval obtained by dividing one horizontal scanning period, the receiving side uses the first and second luminance signals based on the synchronization signal. It becomes possible to reliably reproduce a color video signal from the color signal of the color signal.
Furthermore, since the luminance signal and the first and second color signals are provided for each horizontal scanning period, the vertical resolution of the color signals does not deteriorate. Therefore, by applying the present invention to a video tape recorder, for example, each component signal that makes up a color video signal can be efficiently recorded and played back on a single track, and the helical scan method can be used. Even when adopted, each component signal of a high-resolution color video signal can be faithfully reproduced based on the synchronization signal without deterioration of image quality due to crosstalk between adjacent tracks. Therefore, according to the present invention, the intended purpose can be fully achieved.

[Brief explanation of drawings]

1 to 4 show an embodiment in which the present invention is applied to a video tape recorder. FIG. 1 is a block diagram of a recording system signal processing circuit, and FIG.
The figure is a time chart for explaining the operation of the recording system signal processing circuit, FIG. 3 is a waveform diagram of the synchronization signal superimposed on the time-series signal in the recording system signal processing circuit, and FIG. 4 is a reproduction diagram. FIG. 2 is a block diagram showing the configuration of a system signal processing circuit. 3, 5, 7... A/D converter, 4, 6, 8... Time axis compression circuit, 9... Data selector, 10... D/A
Converter, 15... Clock signal forming circuit, 16... Synchronizing signal generator.

Claims (1)

[Claims] 1. The luminance signal and the first and second color signals constituting the color video signal are time-base compressed, and each of the time-base compressed signals is time-division multiplexed and converted into a time-series signal. In a color video signal processing circuit that outputs a color video signal, one horizontal scanning period is divided into three sections, first to third, blanking sections are provided at predetermined intervals within each section, and a synchronizing signal is applied to each blanking section. The time-axis compressed luminance signal is placed in each section of the one horizontal scanning period, and the time-axis compressed first color signal is placed in the second section. 2. A color video signal processing circuit, wherein the second color signal is placed in the third section in combination with the luminance signal and outputs a time-division multiplexed time-series signal.