JPH0775420B2 - Recording / playback device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus suitable for use in time-series transmission, for example recording / reproducing, of a color television signal by increasing a compression ratio of a color difference signal rather than a luminance signal.

[0002]

2. Description of the Related Art Conventionally, in a VTR (video tape recorder), for example, a color signal is recorded as amplitude and phase information. However, this causes a problem that reproduction causes deterioration of color reproducibility during reproduction. . Therefore, in recent years, a method of recording / reproducing a color signal with only the same amplitude information as the luminance signal has been proposed. That is, the luminance signal and the color difference signal are respectively time-axis compressed into a time series signal, and the time series signal is recorded and reproduced.

12 and 13 show a recording system and a reproducing system of such a VTR. In FIG. 12, a composite color television signal Sv (shown in FIG. 14A) is supplied to the terminal 1, and the television signal Sv is the luminance / luminance /
It is supplied to the color separation circuit 2. The luminance signal Y (shown in FIG. 14B) obtained from the separation circuit 2 is supplied to the time base compression circuit 3. The color signal C obtained from the separation circuit 2 is supplied to the color demodulation circuit 4. And this color demodulation circuit 4
The red color difference signal RY (shown in FIG. 14C) and the blue color difference signal BY (shown in FIG. 14D) are obtained from these, and these are supplied to the compression circuit 3.

In the compression circuit 3, the luminance signal Y and the color difference signals RY and BY which are supplied have a compression ratio of the color difference signals R-Y and BY that is larger than that of the luminance signal Y, and time compression is performed. As shown in FIG. 14E.
A TCI (Time Compressed Integration) television signal STCI as shown in FIG.

The television signal STCI is supplied to the FM modulator 6 via the pre-emphasis circuit 5.
Incidentally, instead of the FM modulator 6, an AM modulator or PM
It may be a modulator or the like. The FM-modulated television signal STCI is supplied to the magnetic head 7 and recorded on the magnetic tape 8.

Next, in FIG. 13, the FM-modulated television signal STCI reproduced from the magnetic tape 8 by the magnetic head 9 is supplied to the FM demodulator 10 and demodulated. The television signal STCI obtained from the FM demodulator 10 is supplied to the post-time axis expansion circuit 12 via the de-emphasis circuit 11.

In the expansion circuit 12, the compression circuit 3 described above is used.
On the output side, the luminance signal Y (illustrated in FIG. 14B), the color difference signals RY (illustrated in FIG. 14C), and BY (illustrated in FIG. 14D), which have been expanded on the normal time axis, are respectively processed. Shown in FIG.

Luminance signal Y obtained from the expansion circuit 12
Is supplied to the combiner 13. Further, the color difference signals R-Y and B-Y obtained from the expansion circuit 12 are supplied to the color modulation circuit 14 and are quadrature-phase modulated with a color subcarrier of 3.58 MHz, for example. The color signal C obtained from the modulation circuit 14 is supplied to the synthesizer 13. And this synthesizer 1
A composite color television signal Sv is obtained at the output terminal 15 derived from 3.

As shown in FIGS. 12 and 13, by recording / reproducing the color difference signal only with the amplitude information as in the case of the luminance signal, the color reproducibility is improved without deterioration of the color reproducibility due to jitter during reproduction. To do.

[0010]

By the way, the luminance signal Y
With regard to (2), a better image can be obtained by visually adding a preshoot and an overshoot, that is, enhancing the high range and performing contour correction. In this case, in the example of FIG. 12 and the example of FIG. 13, the pre-emphasis circuit 5 and the de-emphasis circuit 11 add overshoot and preshoot to the television signal STCI (shown in FIG. 15D), resulting in FIG. As shown in, the preshoot and overshoot are added to the luminance signal Y. However, in this case, the color difference signal R is generated at the stage of the television signal STCI.
The same characteristics as the luminance signal Y are given to −Y and BY. Then, these color difference signals R-Y, B
Since -Y has a large compression ratio, as shown in FIGS. 15B and 15C, the widths of preshoot and overshoot become large at the time of expansion, which is conspicuous and results in deterioration of image quality.

In this sense, as shown in FIGS. 12 and 13, it is not preferable to apply the same pre-emphasis and de-emphasis to the luminance signal Y and the color difference signals RY and BY.

The present invention has been made in consideration of the above points, and an object of the present invention is to propose a recording / reproducing apparatus capable of obtaining a good image by applying emphasis to the luminance signal and the color difference signal with suitable characteristics. It is a thing.

[0013]

According to the present invention, emphasis means 16 and 1 have different emphasis characteristics for a luminance signal and a color difference signal of a time division multiplexed video signal.
7 and 18, the luminance signal and the color difference signal are time-axis compressed so that the compression ratio of the color difference signal is larger than that of the luminance signal, and the time-axis-compressed luminance signal and color difference signal are arranged in time series after the synchronization signal. The time axis compression means 3 for generating a time division multiplexed video signal, the recording means 6, 7 for recording the time division multiplexed video signal on the recording medium 8, and the time division multiplexed video signal recorded on the recording medium 8. Reproducing means 9 and 10 for reproducing, time axis expanding means 12 for expanding the time axis of the luminance signal and color difference signal of the reproduced time division multiplexed video signal, and luminance signal and color difference signal of the reproduced time division multiplexed video signal. And de-emphasis means 19, 20 and 21 having different de-emphasis characteristics with respect to.

[0014]

According to the present invention described above, the emphasis means 1
6, 17, and 18 have different emphasis characteristics for the luminance signal and the color difference signal, and the time axis compression unit 3 performs time axis compression of the luminance signal and the color difference signal so that the compression ratio of the color difference signal is larger than that of the luminance signal. Then, the time-axis compressed luminance signal and color difference signal are arranged in time series after the synchronization signal to generate a time division multiplexed video signal, and the recording means 6 and 7 record the time division multiplexed video signal on the recording medium 8. Then, the time division multiplexed video signal recorded on the recording medium 8 is reproduced by the reproduction means 9 and 10, and the time axis of the luminance signal and the color difference signal of the reproduced time division multiplexed video signal is timed by the time axis expansion means 12. The de-emphasis characteristics of the time-division-multiplexed video signal which is axially expanded and reproduced with respect to the luminance signal and the color difference signal are made different by the de-emphasis means 19, 20, and 21, respectively.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the recording / reproducing apparatus of the present invention will be described below with reference to FIGS. 1 and 2, parts corresponding to those in FIGS. 12 and 13 are designated by the same reference numerals, and detailed description thereof will be omitted. In addition, in the following description, FIG.
See part 4 of the drawings.

In FIG. 1 (recording system), the luminance signal Y obtained from the separation circuit 2 is supplied to the compression circuit 3 via the pre-emphasis circuit 16. The red color difference signal RY and the blue color difference signal BY obtained from the color demodulation circuit 4 are compressed by the compression circuit 3 via the pre-emphasis circuits 17 and 18, respectively.
Is supplied to. The broken lines in FIGS. 3A, 3B and 3C indicate the luminance signal Y and the color difference signals RY and BY, respectively.

Similarly to the example of FIG. 12, the compression circuit 3 obtains a television signal STCI as shown in FIG. 14E, which is supplied to the magnetic head 7 through the FM modulator 6 and the magnetic tape. 8 is recorded.

Next, in FIG. 2 (reproduction system), the television signal STCI obtained from the FM demodulator 10 is supplied to the expansion circuit 12.

From the expansion circuit 12, as in the example of FIG. 13, the luminance signal Y and the color difference signals RY and BY, which are expanded on the normal time axis, are obtained. Then, the luminance signal Y is supplied to the synthesizer 13 via the de-emphasis circuit 19. Further, the color difference signals R-Y and B-Y are supplied to the color modulation circuit 14 via the de-emphasis circuits 20 and 21, respectively. Then, the color signal C obtained from the modulation circuit 14 is supplied to the synthesizer 13. And this synthesizer 13
A composite color television signal Sv is obtained at the output terminal 15 derived from the above.

Further, in the example of FIG. 1 and the example of FIG.
Pre-emphasis circuit 1 provided in the system of luminance signal Y
6. The overall characteristic of the de-emphasis circuit 19 is set to a high frequency emphasis characteristic as shown by the solid line in FIG. 3A. Further, the total characteristics of the pre-emphasis circuit 17 and the de-emphasis circuit 20 provided in the system of the red color difference signal RY and the total characteristics of the pre-emphasis circuit 18 and the de-emphasis circuit 21 provided in the system of the blue color difference signal B-Y. The characteristics are shown in Figure 3, respectively.
As shown by the solid lines B and C, the characteristics are made flat. Others are configured similarly to the example of FIG. 1 and the example of FIG.

In the example of FIG. 1 and the example of FIG. 2, the luminance signal Y passes through the pre-emphasis circuit 16 and the de-emphasis circuit 19, and the red color difference signal RY passes through the pre-emphasis circuit 17 and the de-emphasis circuit 20. The blue color difference signal BY is passed through the pre-emphasis circuit 18 and the de-emphasis circuit 21, and the luminance signal Y and the color difference signal RY,
Different emphasis is applied to BY. That is,
Finally, the luminance signal Y has a high-frequency emphasis characteristic and the color difference signals RY and BY have a flat characteristic.

Therefore, according to the example of FIG. 1 and the example of FIG. 2, suitable emphasis can be applied to the luminance signal Y and the color difference signals RY and BY, and a good image can be obtained. .

Next, FIGS. 4 and 5, FIG. 6 and FIG. 7, FIG. 8 and FIG. 9, and FIG. 10 and FIG. 11 show other embodiments of the present invention. In these figures, parts corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, the examples of FIGS. 4 and 5 will be described.
In FIG. 4 (recording system), a luminance signal Y obtained from the separation circuit 2 and color difference signals RY and B obtained from the color demodulation circuit 4
-Y is supplied to the compression circuit 3, and from this compression circuit 3, FIG.
A television signal STCI as shown in 4E is obtained.
Then, the television signal STCI is supplied to one and the other fixed terminals 24a and 24b of the switch circuit 24 via the pre-emphasis circuits 22 and 23, respectively.

A switching control signal is supplied from the compression circuit 3 to the switch circuit 24 and switched to the terminal 24a side in correspondence with the luminance signal Y of the television signal STCI, while the color difference signal RY of the television signal STCI is supplied. , BY are switched to the terminal 24b side. That is, from the switch circuit 24, the television signal STCI including the luminance signal Y passed through the pre-emphasis circuit 22 and the color difference signals RY and BY passed through the pre-emphasis circuit 23 is obtained.

The television signal STCI is supplied to the magnetic head 7 via the FM modulator 6 and recorded on the magnetic tape 8.

Next, in FIG. 5 (reproduction system), the television signal STCI obtained from the FM demodulator 10 is supplied to the de-emphasis circuits 26 and 27 via the switch circuit 25. Then, these de-emphasis circuits 26 and 2
The output of 7 is supplied to the decompression circuit 12.

In this case, the switch circuit 25 is supplied with the switching control signal from the expansion circuit 12, and the television signal S is supplied.
Corresponding to the luminance signal Y of TCI, it is switched to the terminal 25a side, while the color difference signals RY, B of the television signal STCI.
It is switched to the terminal 25b side corresponding to -Y. Therefore,
The luminance signal Y of the television signal STCI is supplied to the expansion circuit 12 via the de-emphasis circuit 26, while the color difference signals RY and BY are supplied to the expansion circuit 12 via the de-emphasis circuit 27.

From the expansion circuit 12, the luminance signal Y and the color difference signals RY and BY which are expanded on the normal time axis are obtained. The luminance signal Y is supplied to the combiner 13, and the color difference signals RY and BY are supplied to the color modulation circuit 14. Then, the color signal C obtained from the color modulation circuit 14 is supplied to the synthesizer 13. Then, the composite color television signal Sv is obtained at the output terminal 15.

In the example of FIG. 4 and the example of FIG.
The overall characteristics of the pre-emphasis circuit 22 and the de-emphasis circuit 26 are set to the high-frequency emphasis characteristics as shown by the solid line in FIG. 3A. In addition, the pre-emphasis circuit 23,
The overall characteristic of the de-emphasis circuit 27 is made flat as shown by the solid line in FIG. 3B or C.

Others are similar to those of the example of FIG. 1 and the example of FIG. In the example of FIG. 4 and the example of FIG. 5, the luminance signal Y passes through the pre-emphasis circuit 22 and the de-emphasis circuit 26, and the color difference signals RY and BY pass through the pre-emphasis circuit 23 and the de-emphasis circuit 27. Through
Different emphasis is applied to each. That is, the luminance signal Y is finally set to have a high-frequency emphasis characteristic, and the color difference signal R
-Y and BY have flat characteristics.

Next, the example of FIG. 6 and the example of FIG. 7 will be described. In FIG. 6 (recording system), the luminance signal Y obtained from the separation circuit 2 is supplied to the compression circuit 3 via the pre-emphasis circuit 28, and the color difference signals R-Y and B-Y obtained from the color demodulation circuit 4. Is supplied to the compression circuit 3, and from this compression circuit 3, the television signal S as shown in FIG.
TCI is obtained. And this television signal STCI
Is supplied to the magnetic head 7 via the pre-emphasis circuit 29 and the FM modulator 6 and recorded on the magnetic tape 8.

Next, in FIG. 7 (reproduction system), the television signal STCI obtained from the FM demodulator 10 is supplied to the expansion circuit 12 via the de-emphasis circuit 30.

From the expansion circuit 12, the luminance signal Y and the color difference signals RY and BY which are expanded on the normal time axis are obtained. Then, the luminance signal Y is the de-emphasis circuit 3
It is supplied to the synthesizer 13 via 1. In addition, the color difference signal R
-Y and BY are supplied to the color modulation circuit 14, and the color signal C obtained from them is supplied to the synthesizer 13. Then, the composite color television signal Sv is output to the output terminal 11.
Is obtained.

Further, in the example of FIG. 6 and the example of FIG.
The total characteristics of the pre-emphasis circuits 28 and 29 and the de-emphasis circuits 30 and 31 are set to high-frequency emphasis characteristics as shown by the solid line in FIG. 3A. The total characteristics of the pre-emphasis circuit 29 and the de-emphasis circuit 30 are shown in FIG.
As shown by the solid line of B or C, it has a flat characteristic. Otherwise, the configuration is the same as in the examples of FIGS. 1 and 2.

In the examples of FIGS. 6 and 7, the luminance signal Y is passed through the pre-emphasis circuits 28 and 29 and the de-emphasis circuits 30 and 31, and the color difference signals R-Y and B-Y.
Is a pre-emphasis circuit 29 and a de-emphasis circuit 30.
Different emphasis is applied to each. That is, finally, the luminance signal Y has a high-frequency emphasis characteristic, and the color difference signals RY and BY have a flat characteristic.

Next, the examples of FIGS. 8 and 9 will be described. In FIG. 8 (recording system), the luminance signal Y obtained from the separation circuit 2 is supplied to the compression circuit 3, and the color difference signals RY and BY obtained from the color demodulation circuit 4 are pre-emphasis circuit 32 and respectively. It is supplied to the compression circuit 3 via 33, and the television signal STCI as shown in FIG. 14E is obtained from the compression circuit 3. The television signal STCI is supplied to the magnetic head 7 via the pre-emphasis circuit 34 and the FM modulator 6 and recorded on the magnetic tape 8.

Next, in FIG. 9 (reproduction system), the television signal STCI obtained from the FM demodulator 10 is supplied to the decompression circuit 12 via the de-emphasis circuit 35.

From the expansion circuit 12, the luminance signal Y and the color difference signals RY and BY which are expanded on the normal time axis are obtained. Then, the luminance signal Y is supplied to the combiner 13. The color difference signals R-Y and B-Y are supplied to the color modulation circuit 14 via the de-emphasis circuits 36 and 37, respectively, and the color signal C obtained therefrom is supplied to the synthesizer 13. Then, the composite color television signal Sv is obtained at the output terminal 15.

Further, in the example of FIG. 8 and the example of FIG.
The total characteristics of the pre-emphasis circuit 34 and the de-emphasis circuit 35 are set to the high-frequency emphasis characteristics as shown by the solid line in FIG. 3A. In addition, the pre-emphasis circuit 32,
34, total characteristics of the de-emphasis circuits 35 and 36, and pre-emphasis circuits 33 and 34, de-emphasis 35,
The overall characteristics of 37 are made flat as shown by the solid lines in FIGS. 3B and 3C, respectively.

Others are similar to those of the example of FIG. 1 and the example of FIG. In the example of FIG. 8 and the example of FIG. 9, the luminance signal Y passes through the pre-emphasis circuit 34 and the de-emphasis circuit 35, and the color difference signal RY passes through the pre-emphasis circuits 32 and 34 and the de-emphasis circuits 35 and 36. The color difference signal BY is passed through the pre-emphasis circuit 33, 3
4. Through the de-emphasis circuits 35 and 37, different emphasis is applied to the luminance signal Y and the color difference signals RY and BY. That is, finally, the luminance signal Y has a high-frequency emphasis characteristic, and the color difference signals RY and BY have a flat characteristic.

Next, the example of FIG. 10 and the example of FIG. 11 will be described. The example of FIG. 10 and the example of FIG. 11 are examples applied to broadcasting, for example, satellite broadcasting. In FIG. 10 (transmission system), the television signal STCI from the compression circuit 3 is supplied to the transmission antenna 39 via the transmitter 38. Further, in FIG. 11 (reception system), the signal obtained from the reception antenna 40 is supplied to the receiver 41, and this receiver 41
As a result, the television signal STCI is obtained and supplied to the decompression circuit 12. Others are configured similarly to the example of FIG. 1 and the example of FIG.

In the example of FIG. 10 and the example of FIG. 11 as well, similarly to the example of FIG. 1 and the example of FIG. 2, the luminance signal Y is finally made to have a high-frequency emphasis characteristic, and the color difference signals RY, B
It has a flat characteristic for −Y.

As described above, also in the other embodiments (shown in FIGS. 4 to 11), the luminance signal Y and the color difference signals RY and B are obtained.
-Y is subjected to different emphasis, and finally the luminance signal Y is given a high-frequency emphasis characteristic, and the color difference signal R-
Since Y and B-Y have flat characteristics, it is possible to obtain the same effects as those of the example of FIG. 1 and the example of FIG. 2 described above.

As described above, in this embodiment, the pre-emphasis circuits 16, 17, and 18 have different emphasis characteristics for the luminance and color difference signals, and the time axis compression circuit 3 has a greater compression ratio of the color difference signals than the luminance signals. So that the luminance signal and the color difference signal are respectively time-axis compressed, and the time-axis-compressed luminance signal and color difference signal are time-sequentially arranged after the synchronization signal to generate a time-division multiplexed video signal,
After being modulated by the FM modulation circuit 6, it is recorded on the magnetic tape 8 by the magnetic head 7, the time division multiplexed video signal recorded on the magnetic tape 8 is reproduced by the magnetic head 9, and this signal is FM-modulated by the FM demodulation circuit 10. divides multiplexed video signal of the luminance signal and the time-base-decompressed time axis of the color difference signal in the time base expansion circuit 12 when reproducing, the de-emphasis characteristic for the luminance signal and color difference signal division multiplexed video signal when played back and the de-emphasis circuit 19, 20, 21 as to respectively different, that is, since the cause of the emphasis characteristic for the luminance signal and color difference signals, respectively different, can apply a good optimal emphasis relative to each, good Images can be obtained.

The CATV can also be configured in the same manner as the example of FIG. 10 and the example of FIG.

[0047]

According to the present invention described above, the emphasis means for the luminance signal and the color difference signal are made different from each other in the emphasis means, and the time axis compression means
Time-division multiplexed video in which the luminance signal and color-difference signal are time-axis compressed so that the compression ratio of the color-difference signal is larger than that of the luminance signal, and the time-axis-compressed luminance signal and color-difference signal are arranged in time series after the synchronization signal. A signal is generated, the time division multiplex video signal is recorded on the recording medium by the recording means, the time division multiplex video signal recorded on the recording medium is reproduced by the reproduction means, and the luminance of the reproduced time division multiplex video signal The time axis of the signal and the color difference signal is expanded by the time axis expanding means so that the de-emphasis characteristics of the reproduced time division multiplexed video signal with respect to the luminance signal and the color difference signal are made different by the de-emphasis means. , can apply a good optimal emphasis relative to each, it is possible to obtain a good image.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a recording side of an embodiment of a recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram showing the reproducing side of an embodiment of the recording / reproducing apparatus of the present invention.

FIG. 3 is a graph for explaining characteristics of pre-emphasis and de-emphasis, which is used for explaining one embodiment of the recording / reproducing apparatus of the present invention.

FIG. 4 is a block diagram showing the recording side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 5 is a block diagram showing the reproducing side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 6 is a block diagram showing the recording side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 7 is a block diagram showing the reproducing side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 8 is a block diagram showing the recording side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 9 is a block diagram showing the reproducing side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 10 is a block diagram showing the transmitting side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 11 is a block diagram showing the receiving side of another embodiment of the recording / reproducing apparatus of the present invention.

FIG. 12 is a block diagram of a recording side showing an example of a conventional recording / reproducing apparatus.

FIG. 13 is a configuration diagram on the reproducing side showing an example of a conventional recording / reproducing apparatus.

FIG. 14 is a waveform chart provided for explaining a conventional recording / reproducing apparatus.

FIG. 15 is a waveform chart for explaining a conventional recording / reproducing apparatus.

[Explanation of symbols]

 2 Luminance / color separation circuit 3 Time axis compression circuit 4 Color demodulation circuit 6 FM modulator 10 FM demodulator 12 Time axis expansion circuit 13 Combiner 14 Color modulation circuit 16, 17, 18 Pre-emphasis circuit 19, 20, 21 De-emphasis circuit

Claims (1)

[Claims] 1. Emphasis means for making emphasis characteristics different for a luminance signal and a color difference signal, respectively, and the luminance signal and the color difference signal are time-axis compressed so that the compression ratio of the color difference signal is larger than that of the luminance signal, respectively. Time-axis compression means for generating the time-division multiplexed video signal by arranging the time-axis compressed luminance signal and the color difference signal in time series after the synchronization signal, and recording the time-division multiplexed video signal on a recording medium. Recording means, reproducing means for reproducing the time division multiplexed video signal recorded on the recording medium, and time axis expansion means for expanding the time axis of the luminance signal and the color difference signal of the reproduced time division multiplexed video signal. And a de-emphasis means for changing the de-emphasis characteristics of the reproduced time-division multiplexed video signal with respect to the luminance signal and the color difference signal. Recording reproducing apparatus according to claim.