JPH01226294A - Recording and reproducing device for color video signal and sound signal - Google Patents

Abstract

PURPOSE:To improve an S/N and the reproducibility of hue by recording and reproducing a luminance signal Y and color difference signals (B-Y), (R-Y) and a sound signal on/from an optical disk by time-division-multiplexing them. CONSTITUTION:A color composite signal and the sound signal are converted into signals Sc, Sa, Sr, and further, are recorded on the optical disk. The signal Sc is the signal to be recorded during an effective vertical scanning period, and it contains a horizontal sync signal SYNC consisting of a sine-wave-shaped burst signal, sound data ADDT, the color difference signals Bc, Rc and the luminance signal Yc in its one horizontal period in said order. Accordingly, the luminance signal and the color difference signals (B-Y), (R-Y) are time- division-multiplexed, and simultaneously, at this time, the sound signal is recorded on the optical disk as being distributed in the horizontal blanking period and the vertical blanking period of an original color signal (Y+C).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording and reproducing system for color video signals and audio signals.

[Summary of the invention]

The present invention provides a method for recording luminance signals, color signals, and audio signals into signals of a predetermined format by compressing the time axis on an optical disc, for example, in which the horizontal synchronization signal is made into a burst sine wave, and the video signal level is It is designed to be inserted inside.

[Conventional technology]

As a method of recording color video signals and audio signals on an optical disc, there is a method of recording them using frequency spectra as shown in FIGS. 8(A) and 8(B), for example.

That is, the method shown in FIG. 3A has been put to practical use in laser discs, and an FM signal (Y+C) FM that is FM-modulated by a color composite signal and an FM signal AFM that is FM-modulated by an audio signal are used. Frequency multiplexed and recorded.

In addition, the method shown in FIG. 3B is also in practical use in home VTRs, and uses an FM signal YFM that is FM modulated by a luminance signal, a carrier color signal C that has been low-frequency converted,
The FM signal AFM which is FM modulated by the audio signal is frequency multiplexed and recorded.

However, when trying to record or reproduce a video signal consisting of such a frequency spectrum with a recording/reproducing device consisting of a disk, an optical head, etc., due to the nonlinearity of the recording/reproducing system, there is generally a difference between the signal YFlt and the AFM, or Cross-modulation occurs between the signals YFM, C, and AFM, and the S/N of the reproduced screen deteriorates.

In addition, with the method shown in FIG. 5A, it is difficult to manage the phase of the carrier color signal included in the color composite signal.
Poor color reproduction. Furthermore, the method shown in FIG. 3B has a problem in that a time lag is likely to occur between the luminance signal and the color signal during reproduction.

Therefore, the present applicant first compressed the luminance signal for one horizontal period and the two color difference signals for the horizontal period in a recording device that records color video signals and audio signals on an optical disk. to form a time-base compressed signal for one horizontal period, digitize the audio signal, compress the time-base, and time-division multiplex the time-base compressed digital audio signal with the above-mentioned time-base compressed signal. Apparatus for recording division multiplexed signals onto an optical disk (Patent Application No. 1983-914J9)
proposed.

[Problem that the invention seeks to solve]

When color video signals and audio signals are recorded using the above-described time division multiplexing method, each signal component is prevented from being cross-modulated due to nonlinearity in the recording/reproducing system, and the S/N ratio can be improved.

However, in order to record or reproduce a signal by time division multiplexing, it is necessary to compress or expand the time axis of the signal, and for this operation, when recording, first the A/D
Signal processing is required to convert the signal into a digital signal using a converter, then compress the time axis in the digital signal state and convert it back to an analog signal using a D/A converter.

Also, during reproduction, the analog signal reproduced from the optical disc is converted into a digital signal by an A/D converter, and then,
Signal processing is required to extend the time axis and return to the original baseband signal, and then convert it into an analog signal using a D/A converter.

By the way, as is well known, when converting into a digital signal using an A/D converter, quantization noise is generally generated. If this is repeated, a problem arises in that the image quality deteriorates in the case of image signals.

Therefore, conventionally, in the case of image signals, the synchronization signal part that is periodically output is extracted and extracted before processing the video signal.
A recording and reproducing method that performs digital signal processing by A/D+D/A converting only the remaining video signal level, and then synthesizes the extracted synchronization signal portion with an image signal demodulated into an analog signal. It is considered.

However, since such a recording and reproducing method requires replacing the synchronization signal every time recording and reproduction, there is a problem that the accuracy of the synchronization signal deteriorates due to repeated dubbing, etc.
In addition, especially in the case of the time division multiplexing method described above, the width of the synchronization part is required to be narrowed (in order to increase the effective signal part within the horizontal period), so there is also a problem with the stability of the synchronization signal. It has the disadvantage of leaving behind.

[Means for solving problems]

The present invention has been made in view of these problems.
First, the time axes of the luminance signal and color difference signal that form the video signal are compressed to produce a signal whose time axes are compressed so that they are located within one horizontal period, and are further recorded on an optical disk together with the audio data converted to PCM code. In addition to forming a color video signal that can be reproduced, a sine waveform whose amplitude level is within the range of the video level and has a predetermined period is used as a synchronization signal for the time-division multiplexed video signal. It is configured to insert a burst signal.

□ [Operation] Since the level of the synchronization signal is set within the same level range as the video signal, the maximum conversion code and minimum conversion code of the A/D converter that converts to a digital signal are set to the maximum value of the video signal ( white level) and minimum value (black level) to reduce sampling noise.
Since the synchronization signal includes only a sinusoidal signal component having a single frequency, the precision of the synchronization position can be increased.

〔Example〕

First, to explain the recording signal format on the optical disc of the present invention, Figures 2A and 3A show standard NTSC color composite signals (y + c) for comparison. where, Y is a luminance signal, C is a carrier color signal (not shown), Sb is a burst signal, Ph is a horizontal synchronization pulse, and P
v is the vertical synchronization pulse. (FIG. 2A shows the waveform in the case of a color bar.) Then, the color composite signal and the audio signal are the signals Sc shown in FIGS. 2B-D and FIG. 3B showing a longer period signal, The signal is converted into Sa, Sr, and further converted into an FM signal Sf before being recorded on an optical disc.

That is, the signal Sc is a signal recorded during an effective vertical scanning period (non-vertical blanking period), and this signal Sc
has a horizontal synchronizing signal 5YNC2 audio data ADDT, color difference signals Bc and Rc, and a luminance signal YC in this order, each consisting of a sinusoidal burst signal during one horizontal period.

In this case, the horizontal synchronization signal 5YNC is the horizontal synchronization pulse P
This is sinusoidal synchronization information newly formed separately from h, and is positioned at a predetermined period at the beginning of each horizontal period, as will be described later. The audio data ADDT is a digital signal with a format that is the same as or similar to the PCM audio signal in 8 mm video, and for example, the stereo audio signals of the left and right channels are sampled at twice the horizontal frequency. At the same time, each sample is A/D converted at a rate of 10 bits, and the 10 bits per sample are compressed to 8 bits per sample, and furthermore, an error correction code, control code, etc. are added to the serial digital signal. It's a signal.

This audio data ADDT is composed of 7 bytes per horizontal period, the first byte of which is a synchronization signal S of a specific bit pattern, and the following 6 bytes are actual audio data. Also, this audio data ADDT
The level is 10.50,9 from the binary signal of 0'' and 1.
This is a signal converted into a ternary signal of 01RE.

In addition, the color signals Bc and Rc are obtained by compressing the blue color difference signal (B-Y) and the red color difference signal (R-Y) by 1/6 times in the time axis during the effective horizontal scanning period of one horizontal period. This is a signal.

Further, the luminance signal Yc is a signal obtained by compressing the luminance signal Y in the effective horizontal scanning period of one horizontal period by 2/3 times on the time axis.

Further, the signal Sa is a signal recorded during the vertical blanking period, and this signal Sa is a horizontal synchronizing signal 5YNC,
and audio data ADDT.

In this case, the first byte of the audio data ADDT is used as a synchronization signal S for audio data, and the following 78 bytes are used as actual audio data. Further, this audio data ADD'T is also a three-value code similar to the above.

Furthermore, the signal Sr is also a signal recorded during the vertical blanking period, but this signal Sr is a reference signal indicating the horizontal line that is the starting point of each field period, and therefore, the synchronizing signal 5YNC and the dummy Audio data ADDT
and a signal REFL with a predetermined level pattern.

Then, as shown in FIG. 3B, the seventh horizontal period from the end of the vertical blanking period is used as the reference signal Sr, then the signal Sa is used for four horizontal periods, and then the signal Sa is used for the next one horizontal period. is set as the signal Sc without the signal Bc-Yc, and is thereafter set as the original signal Sc for approximately 250,000 days. Note that, when viewed from the original color composite signal (Y+C) (FIG. 3A), the vertical synchronizing pulse Pv and the following several horizontal periods are allocated to the track jump period, and it is preferable that only the signal 5YNC be used in this period. .

Then, as described above, the signal St having the signals Sr, Sa', and Sc is converted into the FM signal Sf, and this signal S
So that one frame period of f corresponds to one revolution of the optical disk,
Recorded as a thinly wound track.

Therefore, the luminance signal, color difference signal (B-Y), (R-
Y) and audio signals are time-division multiplexed, and at this time, the audio signals are recorded on the optical disc while being distributed over the horizontal blanking period and vertical blanking period of the original color signal (Y + C). become.

By the way, the synchronization signal 5YNC of the color video signal of the present invention
As shown in the enlarged view of FIG. 4, the section is composed of a pedestal area TP indicating the pedestal level, a burst area TB consisting of a single sinusoidal waveform, and a clamp area Tc which is the θ level of the color difference signal. has been done.

Therefore, the signal level of the synchronization signal 5YNC is within the luminance signal level range of 0 to 100 IRE, and the period of the sinusoidal signal in the burst region TB is, for example, 1.7 M
It is set to H7 (108f H). (846 samples/8 bits) Therefore, the synchronization signal 5YNC is within the same level as the time-axis compressed luminance signal or color difference signal, but as described later, it is a burst-like sine signal of a specific period output every horizontal period. By first detecting the wave and then detecting the specific position of this burst-like sinusoidal signal, the synchronization position can be precisely determined.

Next, an example of the recording/reproducing device will be explained.

In FIG. 1, 1 is an optical disk, 2 is an optical head (recording/reproduction pickup), and the optical disk 1 is a motor 3.
The optical head 2 is rotated at a frame frequency by the optical disc 1, and the optical head 2 is opposed to the optical disc 1.
It is arranged so that it can move in the radial direction of the optical disc 1. At this time, the servo circuit 4 performs various servo controls such as focus servo, tracking servo, slide servo, skew servo, and spindle servo on the optical head 2 and motor 3.

Reference numerals 11 to 43 indicate a recording system, and during recording, a color composite signal (y + c) is sent to the synchronization separation circuit l.
are supplied and extracted horizontal and vertical synchronization pulses Ph,
P, is taken out, and these pulses Ph and PV are supplied to the timing control circuit 18 to form control signals of various timings necessary for recording processing, and these control signals are supplied to the respective circuits.

In addition, the signal (y + c
) is supplied to the Y/C separation circuit 12 to separate the luminance signal Y and carrier color signal C, and this signal C is supplied to the color demodulation circuit 13 to produce blue and red color difference signals (B-Y), ( R-Y)
are demodulated, and these signals (B - Y) and (RY) are sent to the A/D converter 14B of the digital signal processing circuit 10,
14H, and the signal Y is also supplied to the A/D converter 14Y.

In this case, the A/D converters 14Y to 14R include the subsequent memories 15Y to 15R, the multiplexer 16, and the D/A converters 14Y to 14R.
Along with the converter 17, the signals Y, (B-Y), (R,
The A/D converter 17 outputs time-base compressed signals Be, Rc for each horizontal period of the effective vertical scanning period.
, Yc are extracted. And these signals B c ”
Y c is supplied to the adder circuit 21 .

On the other hand, the contents of the ROM 19 in which the waveform data of the synchronization signal (S Y N C) is recorded in advance are read out by the sample period clock output from the timing control circuit 18, and at the same time, the REF
Similarly, the L signal is output as digital data from the ROM 20 and input to the multiplexer 16, and these signals are also output from the multiplexer 16 at predetermined timings, as shown in FIGS. 2 and 3 above. The waveform of the signal arrangement is supplied to the A/D converter 17, where it is converted into an analog signal.

Furthermore, the left and right channel stereo audio signals are input to the input terminal 31L of the audio signal processing circuit 30.

PCM in 8mm video is supplied from 31R to encoder 33 through A/D converters 32L and 32R.
The signal SP is encoded into the same PCM audio signal Sp as the audio signal, and this signal SP is written into the buffer memory 34 and read out at a predetermined timing to become the signal SC.
.

Therefore, the signal St having the signals Sc, s, . . . Sr shown in FIG. 2B-D at the timing shown in FIG.

Then, this signal SL is supplied to the FM modulation circuit 23 through the pre-emphasis circuit 22 to be converted into an FM signal Sf, and this signal Sf is supplied to the recording amplifier 24 to be converted into a pulse train. is supplied to the optical head 2 through the optical disc l.
The data is recorded so that the L field becomes a half-round track and the entire track becomes a thinly wound track.

On the other hand, 41 to 63 indicate a reproduction system. During reproduction, a signal Sf is reproduced from the optical disc l by the optical disc 2, and this signal Sf is transmitted through the reproduction side contact P of the switch 5, and further through the reproduction amplifier 51 and the limiter 52. The signal St is demodulated by being supplied to the FM demodulation circuit 53, and the signal St
is supplied to the synchronization separation circuit 60 through the de-emphasis circuit 54, and the synchronization signal 5YNC is taken out as described later, and is supplied to the reproduction timing control circuit 61 to form various timing control signals necessary for reproduction processing. The control signals are supplied to the reproduction digital signal processing circuit 50 and the audio signal processing circuit 40, respectively.

The signal St from the de-emphasis circuit 54 is A/D.
It is supplied to converter 55. This A/D converter 5
5 is a subsequent memory 56 (TBC) and latches 57Y to 5.
7R and the D/A converters 58Y to 58R constitute the time axis expansion circuit 50, and the signals Y, CB-Y) expanded to the original time axis length from the D/A converters 58Y to 58R, (RY) is taken out.

Then, the signal Y is supplied to the adder circuit 62, and
The signals (B-Y) and (R-Y) are supplied to a modulation circuit 59 to form a carrier color signal C having a burst signal Sb,
This signal C is supplied to an adder circuit 62. therefore,
The output is the original color composite signal (y 10c)
is taken out. Then, an NTSC horizontal synchronizing signal is added from the reproduction timing control circuit 61 by the adder circuit 63 and output as a composite color video signal.

Furthermore, the signal St from the de-emphasis circuit 54 is supplied to the ternary/binary conversion circuit 41 of the audio signal processing circuit 40, and the data ADDT in the signal St is converted into a binary code. The signal SP is sequentially written to and read out at a predetermined timing to extract the signal SP. This signal SP is supplied to the decoder 43, where the error correction of the signal SP and the conversion from 8 bits to 10 bits are performed. After that, the signal is supplied to D/A converters 44L and 44H, where it is D/A converted into the original left and right channel stereo audio signals, which are output to a terminal 45L.

It was taken out in 45H.

FIG. 5 shows a specific embodiment of the synchronization separation circuit 60 for detecting burst-like synchronization information, and FIG. 6 similarly shows its operating waveform signal.

The reproduced signal A obtained from the de-emphasis circuit 54 is passed through the low-pass filter 60 A of the synchronization signal separation circuit 60,
(f c' = 1.7 MHz) and is input to the band pass filter 60B (fO = 1.7 MHz), and the low frequency reproduction signal B whose high frequency signal components have been canceled by the low pass filter 60A is then passed through the pedestal clamp circuit 60C. is input.

As shown in FIG. 6, a threshold detection circuit 60D outputs a binary signal that rises for a predetermined period at a threshold value of almost 0 level of the burst synchronization information.
is input. This binary signal is then input to an eight-stroke wind generation circuit 60H which outputs a wind pulse F.

On the other hand, 1 and 7 extracted by the pan 1' pass filter 60B
The high-frequency reproduction signal C (including burst-like synchronization information) consisting of MHz frequency components is converted into a pulse signal E by the next zero-cross comparator 60F.

This pulse signal E and the above-mentioned wind pulse signal F are generated by a reproduction 5Y, which is composed of, for example, a mono-multivibrator, etc. and a gate circuit, and generates a pulse of almost a horizontal period.
The output pulse G is input to the NC forming circuit 60G and rises at the rising point of the pulse signal E input during the period of the wind pulse F.

As seen in the waveform diagram of FIG. 6, this output pulse G rises at the third wave of burst-like synchronization information and is set to last for a time slightly shorter than the horizontal period. The reference phase of the horizontal synchronization signal is set at the rising point of the third wave of the sine wave signal forming the burst-like synchronization information, making it possible to make the synchronization information extremely accurate.

Note that the z-valued signal that is the output of the threshold detection circuit 600 is formed by the signal obtained by slicing the almost O level of the burst-like synchronization information. A false signal G' is output even at a position other than the synchronization position due to the luminance signal or color difference signal, and the rising point of the pulse signal E is within the wind pulse F' created by this false signal G'. Otherwise, a false synchronization signal may be generated.

Therefore, in the case of the present invention, a lock circuit is formed so that the output pulse G output from the reproduction 5YNC forming circuit 60G is outputted as a signal accurately indicating the horizontal synchronization position.

This lock circuit includes a phase comparator 60H, a loop filter 60I, and a variable voltage generator (VCO).

The J2 frequency divider circuit 60 can include a gate pulse generation circuit 60L and a gate signal output circuit 80M.

The VCO 60J outputs a signal frequency of, for example, 1296 fu±1%, which is frequency-divided by 171296 by the frequency dividing circuit 60, thereby supplying an IH cycle signal to one input of the phase comparator 60H.

The other input of the phase comparator 60H is connected to the above-mentioned reproduction 5.
Since the output pulse G of the YNC forming circuit 60G is input, in the operating state where the VCO 60J is synchronized with the output pulse G, the gate pulse J of the gate pulse generation circuit 60L is input.
is in the same phase as the output pulse G as shown in FIG.
This signal J is transmitted through the gate circuit 60M to the above-mentioned reproduction 5.
The signal H is input to the inhibit terminal of the YNC forming circuit 60G.

Therefore, in the synchronized state, the inhibition input of the reproduction 5YNC forming circuit 60G is canceled within the range of the gate pulse J, and the normal output pulse G output in each IH period is used as the horizontal synchronization information by the reproduction timing control circuit 60.
During the high level period of the gate pulse J, the reproduction 5YNC forming circuit 60
The input of G is prohibited to prevent the above-mentioned erroneous synchronization information from being output.

In addition, an erroneous output pulse G with an indefinite period may be generated at the intended stage of operation.
' is input, this output pulse G' does not match the output of the gate pulse generation circuit 60L, and lock/
The unlock determination circuit 6ON operates and prohibits the output of the gate pulse J by the signal engineer. Therefore, the normal output pulse G including the false output pulse G' is also output from the reproduction 5YNC forming circuit 60G, but the VCO 60
J is reset by a regular output pulse G, and this P
When the LL circuit synchronizes with the horizontal period, the phase of the gate pulse J and the regular output pulse G match, and if this state continues for more than 2 to 3 horizontal periods, the lock/unlock determination circuit 6ON An H level signal that opens circuit 60M is output.

Then, from then on, a signal H equal to the gate pulse J output for each IH period is input to the inhibition terminal of the reproduction 5YNC forming circuit 60G, and a locked state is established in which only the output pulse G is output from the reproduction 5YNC circuit 60G. False output pulses G' are inhibited at the input side of the regenerative 5YNC forming circuit 60G to prevent a return to a false synchronization state.

Note that since there is no image signal during the vertical synchronization blanking period, the synchronization state can be easily achieved at least during this period. Then, when the device enters the -degree synchronization state, it becomes possible to capture and output only the synchronization information from the powerful wind gate operation.

Note that the synchronization separation method described above is an example, and the synchronization position can be detected from burst-like synchronization information using other methods, but in any case, the synchronization information of the present invention is a single embodiment. Since the synchronization reference point is formed at a frequency of

〔Effect of the invention〕

As explained above, according to the present invention, the luminance signal Y,
Since the color difference signals (B-Y), (R-Y) and the audio signal are time-division multiplexed and recorded and reproduced on the optical disk, even if the recording and reproduction characteristics of the optical disk and optical head are non-linear, the luminance signal Y It is possible to obtain a playback screen with a good S/N ratio without causing cross-modulation between the color difference signal (B-Y), (R-Y), or between the audio signal and the color difference signal (B-Y), (R-Y). B-Y) and (R-Y) are also the same FM as the luminance signal Y.
Recording and reproduction are performed using signals, so the S/N ratio is good.
The color reproduction is also good.

Furthermore, the audio signal data ADDT is the original signal (y
Since the signals Yc', Be, and R are distributed over the horizontal blanking period and vertical blanking period of +c),
The period occupied by e can be lengthened, and therefore the time axis compression ratio can be reduced accordingly, and the signal Y c ” R
Since the highest frequency of c can be suppressed, recording and reproduction on the optical disk becomes easier, and the S/N ratio also improves from this point of view.

Furthermore, in the present invention, the synchronization information is formed by a sinusoidal burst signal with a predetermined period, and is digitally processed together with the image data so that it can be recorded and reproduced. There will be no separation, and the synchronization position will not shift due to dubbing or the like.

Also, since the synchronization information is a burst-like sine wave,
The synchronization position has many advantages, such as being able to detect the synchronization position very accurately.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an example of the present invention, Figs. 2 and 3 are signal waveform diagrams for explaining the same, and Fig. 4 is an enlarged waveform diagram of a synchronization signal employed in the recording/reproducing method of the present invention. , FIG. 5 is a block diagram showing an example of a synchronization signal separation circuit, FIGS. 6 and 7 are signal waveform diagrams for explaining the synchronization separation circuit, and FIG. 8 is a conventional recording signal of a video signal and an audio signal. FIG. In the figure, 1 is an optical disk, 2 is an optical head, 11 to 32 are recording system blocks, and 40 to 63 are playback system blocks. (A) (E3) 8th

Claims (4)

[Claims] (1) A time-axis compressed signal obtained by time-axis compressing a luminance signal for one horizontal period and two color difference signals for one horizontal period, and a time-axis compressed signal that is digitized and time-axis compressed. A time-division multiplexed signal in which the digital audio signal obtained is time-division multiplexed with the time-base compressed signal, and a synchronization signal added with a sinusoidal burst signal of a predetermined period that changes within the video signal level is arranged within one horizontal period. 1. A recording device for color video signals and audio signals, characterized in that it records on an optical disc. (2) A color video signal and audio signal recording device according to claim (1), characterized in that a part of the time-axis compressed digital audio signal is dispersed in a vertical blanking period. . (3) A time-axis compressed signal obtained by time-axis compressing a luminance signal for one horizontal period and two color difference signals for one horizontal period, and a time-axis compressed signal that is digitized and time-axis compressed. A time-division multiplexed signal in which the digital audio signal obtained is time-division multiplexed with the time-base compressed signal, and a synchronization signal added with a sinusoidal burst signal of a predetermined period that changes within the video signal level is arranged within one horizontal period. 1. A color video signal and audio signal reproducing device, characterized in that the color video signal and audio signal are read out from an optical disk. (4) The color video signal and audio signal reproducing device according to claim (3), characterized in that a part of the time-axis compressed digital audio signal is dispersed in a vertical blanking period. .