JPS60232795A - Recording and reproducing device of color video signal - Google Patents

Abstract

PURPOSE:To remove a crosstalk component and to improve recording density by recording the hue signal component of a color video signal so that the phase type of said component is changed in accordance with the even or odd number in a guide groove formed in a disc like recording carrier. CONSTITUTION:A color video signal to be recorded is inputted to a terminal 1, a separated 3 horizontal synchronizing signal is supplied to a multiplexer 4 and a PS processing circuit 5 and separated luminance signal component and hue signal component are supplied to a frequency modulators 10, 9 respectively. The modulated signals are supplied to a semiconductor laser driving circuit 12 through an adder 11 and recorded on a track of the disc-like recording medium 15. An even/odd signal S2 obtained from an address signal detected by an optical pickup 13 and a rotational signal S3 obtained from a rotation detecting circuit 19 are supplied to a PS control circuit 6 and a PS control signal S1 for switching the direction turning the phase by 90 deg. in each 1H on the even and odd tracks is switched to the circuit 5. Thus, crosstalk interference at a reproducing time can be reduced and the recording density can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for recording and reproducing color video signals on a disc-shaped record carrier.

(Conventional structure and its problems) In recent years, with the development of high-output semiconductor lasers and highly sensitive recording materials, a new form of video that uses laser beams to record and reproduce color video signals on a disk-based record carrier has been developed. A signal recording and reproducing device is proposed.

This type of recording/playback device records only one screen per rotation, making it easy to capture frames and continuous shots, and because it uses a non-contact method that uses a laser beam, there is no deterioration during playback. Compared to a VTR that uses magnetic tape as a recording medium, it has many advantages such as the ability to jump, slow motion and quick motion playback without noise, and the ability to instantly search any recorded screen. It has the excellent characteristics of
Image files and computers that were difficult to handle with VTRs
It is expected to be applied in fields such as graphics.

In the above-mentioned color video signal recording and reproducing apparatus, the NTSC color video signal to be recorded is separated into a luminance signal component and a color difference signal component, and the luminance signal component is frequency modulated to occupy a relatively high frequency band. The color difference signal component is converted to a lower frequency and added to the frequency-modulated luminance signal component to obtain a composite signal by frequency multiplexing. The recording laser beam obtained by modulating the output intensity of the semiconductor laser with this composite signal is irradiated onto a guide groove (hereinafter referred to as a track) formed in advance on the disc-shaped record carrier, and the output intensity of the semiconductor laser is modulated according to the intensity of the laser beam. Causes a change in reflectance.

Further, a number is added to this track for each round, and by searching for the number, recording can be performed from any position.

In the case of reproduction, by irradiating a reproduction laser beam with a constant low intensity and reading the change in reflectance caused by the recording laser beam, an FM-modulated luminance signal and a color difference signal whose frequency has been converted to a low frequency are reproduced. The original NTSC color video signal is restored from these signals and supplied to the TV receiver.

The disk-shaped record carrier is rotated at 1800 rpm, and one frame of video signal is recorded per rotation. Therefore, images can be searched frame by frame using the address signal indicating the number added every round.

In addition, the pre-formed address signal interferes with the video signal that will be recorded later, but in order to avoid disturbing the screen, the address signal that is formed in advance is only used during the vertical retrace period of the video signal, which is located at two points per rotation. configured to exist.

The recording density of the video signal recording and reproducing device configured as described above is determined by the track pitch (hereinafter referred to as track pitch), but if this pitch is made too narrow, crosstalk from adjacent tracks will occur, causing the screen to be distorted. cause disturbance. The amount of this crosstalk changes not only depending on the track pitch but also the wavelength of the semiconductor laser used and the NA of the objective lens.

In addition, the degree of interference due to crosstalk differs between the luminance signal component and the color difference signal component, and the luminance signal component is frequency-modulated and recorded, so it is less susceptible to interference due to crosstalk, but the color difference signal component is recorded using a low-frequency conversion recording method. Therefore, it is susceptible to interference due to crosstalk.

Therefore, if crosstalk in color difference signal components can be eliminated, the track pitch can be made narrower and the recording density can be increased. The method uses one semiconductor laser for recording, uses two recording heads like a home VTR, and records and reproduces color difference signal components with different phase forms depending on the heads.

It is difficult to increase the recording density because it cannot be configured to remove crosstalk components.

(Object of the Invention) In view of the above-mentioned drawbacks, the present invention makes it possible to make the phase forms of color difference signal components different in adjacent tracks even in recording with a single semiconductor laser, and to remove crosstalk components of color difference signal components during reproduction. The present invention provides a color video signal recording and reproducing device with greatly improved recording density.

(Structure of the Invention) In order to achieve this object, in the color video signal recording and reproducing apparatus of the present invention, the track numbers are classified into two, odd tracks and even trunks, depending on whether the track numbers are odd or even numbers.
The phase of the low-frequency conversion color difference signal is processed and recorded differently for odd-numbered tracks and even-numbered tracks. To play,
Based on the track number, it is determined whether it is an odd track, a track, or an even track, and the phase of the color difference signal is restored based on the result. Crosstalk components from adjacent tracks are They try to cancel each other out.

When recording as described above, it is necessary to read the address signal using a recording laser beam, but unlike a reproduction laser beam, the recording laser beam is a beam modulated by the video signal to be recorded, so it is difficult to read the address signal. Easy to cause errors. Therefore, in the embodiment of the present invention, one rotation of the disk-shaped record carrier is detected, and the phase processing of the low-frequency conversion color difference signal to be recorded is switched based on this result.

When reproducing a disc-shaped record carrier recorded in this way,
If the phase of the color difference signal is restored using only the results of reading the address signals recorded at two locations on one track as described above, when skipping tracks for slow motion or quick motion special playback, the next address signal The color difference signal cannot be restored correctly until it is read. Therefore,
In the embodiment of the present invention, the phase processing of the color difference signal components is switched every time a track is skipped, so that the color difference signal components can always be correctly restored.

(Description of Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a recording block diagram of a color video signal recording and reproducing apparatus in an embodiment of the present invention. In the figure, an NT'SC color video signal to be recorded is input to a terminal 1, and is supplied to a Y/C separator 2 and a sync separator 3. A sync separator 3 separates a horizontal sync signal from the video signal, and this signal is supplied to a multiplier circuit 4 and a PS processing circuit 5. The multiplier circuit 4 generates a signal that is, for example, 160 times the frequency of the horizontal synchronizing signal, and this signal is supplied to the PS processing circuit 5. The PS processing circuit 5 divides the frequency multiplied signal from the multiplier circuit 4 by 4, and uses the control signal S□ from the PS control circuit 6 to change the phase every horizontal period (hereinafter referred to as LH) for odd-numbered trunks, for example. The signal is advanced by 90 degrees, and the phase is delayed by 90 degrees for each IH on even-numbered tracks, and this signal is supplied to the frequency converter 7 as a color subcarrier for low frequency conversion. In the frequency converter 7, from the color subcarrier in the NTSC system supplied from the crystal oscillator 8 and the color subcarrier for low frequency conversion from the PS processing circuit 5,
A signal of the sum of these frequencies is synthesized, and this signal is supplied to the frequency converter 9.

On the other hand, the N,TSC color video signal supplied to the 'l/C separator 2 is separated here into a luminance signal component and a color difference signal component.The luminance signal component is sent to the frequency modulator 1, and the color difference signal component is sent to the It is supplied to a frequency converter 9.

The color difference signal component supplied to the frequency converter 9 is frequency-converted by the low-frequency conversion signal from the frequency converter 7, and the frequency is 40 times the horizontal synchronization signal frequency, and the phase is 90 degrees for each LH on odd-numbered tracks. Go forward, I H on even tracks
A low-pass conversion color difference signal whose phase is delayed by 90 degrees is obtained each time, and this signal is supplied to the adder 11. In the adder 11, this low frequency converted color difference signal.

In the frequency modulator 10, for example, if the carrier frequency is 5
．． The FM signal of 2 to 6.7 MHz is added to the modulated luminance signal component, and this added signal is supplied to the semiconductor laser drive circuit 12. In the semiconductor laser drive circuit 12,
This added signal is amplified and supplied to the optical pick alignment force 3. In the optical pickup 13, the semiconductor laser is driven by this drive signal to generate a recording laser beam, and the recording laser beam is placed on the track of the disk-shaped record carrier 15 which is being rotated at 1800 revolutions per minute by the disk motor 14. A light beam is irradiated and a color video signal is recorded.

Further, the address signal detected by the optical pickup 13 is amplified by the preamplifier 16 and is then amplified by the address signal reading circuit 17.
supplied to In the address signal reading circuit 17.

Address information indicating the track address is read from the address signal and an even/odd signal S2 is supplied to the PS control circuit 6. The PS control circuit 6 is also supplied with a rotation signal S3 indicating the rotation of the disc-shaped record carrier 15 by the one-rotation detection circuit 19, and recording is performed on even tracks where the 1st address signal is an even number and on odd tracks where the 1st address signal is an odd number. A PS control signal S1 is generated to switch the direction in which the phase of the low-pass conversion color difference signal component is rotated by 90 degrees for each IH.

The operation of generating the ps control signal S1 will be explained using the signal waveform diagram in FIG. In the figure, since the recording start track number is 1 and address 1 is being reproduced before the recording start time t1, the even/odd determination result is an odd number and the even/odd signal S2 is "0".

This even/odd signal S2 causes the PS control signal S1 to also be "0".
”. At the same time as recording starts, the constant intensity laser beam that has been used to read the address signal until now is modulated in intensity by the recording signal, making it no longer possible to read the address signal accurately, and the even/odd signal S2 becomes an inaccurate signal. Therefore, after recording address 1, the PS control signal S1 is inverted according to the rotation signal S2. As a result of this, when the track number is an even number, the PS control signal S□ becomes "1", and when the track number is an odd number, the PS control signal S1 becomes "0".

As described above, according to this embodiment, it is possible to stably record color difference signal components whose phases rotate in opposite directions by 90 degrees for each IH on even-numbered tracks and odd-numbered tracks.

FIG. 3 shows a reproduction block diagram of a color video signal recording and reproduction apparatus in an embodiment of the present invention. In the figure, a signal recorded on a disc-shaped record carrier 15 is detected by an optical pickup 13 using a semiconductor laser which is oscillated at a constant output by a semiconductor laser drive circuit 12, and is supplied to a preamplifier 16. In the preamplifier 16,
The detected signal is amplified and passed through a high pass filter 20. The signal is supplied to the low-pass filter 21 and the address signal reading circuit 17. The high-pass filter 20 removes color difference signal components in the low frequency range, and transmits only the luminance FM signal in the high frequency range to the FM demodulator 2.
Supply to 2. In the FM demodulator 22, the luminance FM signal is demodulated to obtain a luminance signal component, and this signal is sent to the adder 2.
3.

Furthermore, the low-pass filter 21 removes the luminance FM signal from the signal amplified by the preamplifier 16 and supplies a low-pass converted color difference signal to the frequency converter 24 . Frequency converter 24
Then, the frequency of the low-pass converted color difference signal is converted to obtain a color difference signal component based on the NTSC system, and this color difference signal component is supplied to the comb-shaped filter 25. In the comb-shaped filter 25, the crosstalk component from the adjacent track is canceled by adding it to the IH-delayed signal to obtain a color difference signal component from which the crosstalk component has been removed, and this color difference signal component is sent to the burst gate circuit 26. It is supplied to an adder 23.

In the adder 23, the color difference signal component from which the crosstalk component has been removed and the FM demodulated luminance signal component are added, and NT
A color video signal based on the SC system is output to 29.

On the other hand, the luminance signal component obtained by the FM demodulator 22 is supplied to the sync separator 3, where the horizontal sync signal component is separated. It is supplied to circuit 5.

In the multiplier circuit 4 and the PS processing circuit 5, I
A low-frequency conversion subcarrier wave whose phase is rotated by 90 degrees every H is generated, and this carrier wave is supplied to the frequency converter 7. Further, the burst gate circuit 26 extracts the burst signal component from the color difference signal component, and supplies this burst signal to the phase comparator 27.

The phase comparator 27 compares the phase of the burst signal with the signal from the crystal oscillator 8 that generates the subcarrier of the NTSC system, and the error signal is supplied to the variable frequency crystal oscillator 28 . The variable frequency crystal oscillator 28 generates a signal with a frequency corresponding to the phase error signal, and this signal is supplied to the frequency converter 7. The frequency converter 7 converts the low-frequency conversion color difference signal whose phase is rotated by 90 degrees for each IH from the low-frequency conversion subcarrier from the PS processing circuit 5 and the signal from the variable frequency crystal oscillator 28 to a constant phase based on the NTSC system. The signals for restoring the color difference signal components are synthesized and supplied to the frequency converter 24.

Also, a disk-shaped record carrier 15 amplified by a preamplifier 16
The reproduced signal is supplied to the address signal reading circuit 17, where the address signal is read.
8. The even/odd discrimination circuit 18 discriminates whether the read address information is an even number or an odd number, and outputs an even/odd signal S2 to P.
It is supplied to the S control circuit 6.

In the PS control circuit 6, this even/odd signal S, , and the terminal 30
A PS control signal S1 is generated from a track jump pulse S4 supplied from
The direction of rotation by 90 degrees is changed every H.

The operation of generating the ps control signal S1 will be explained using the signal waveform diagram in FIG. In FIG. 4, the address signal recorded in one rotation is read at time t2, and as a result of even/odd determination, the even/odd signal becomes "1", and this even/odd signal becomes "1".
The PS control signal S□ becomes "1" based on the odd signal S2. At time t after one round, the next address signal is read, so the even/odd signal S2 becomes "0" and therefore the PS control signal S1 also becomes "0". After that, at time t4, in order to perform special playback, the track is skipped by the track jump pulse S4, and when the adjacent track is played, even/
The odd signal S2 remains in the previous state "0" until time t5 when the next address signal is read, but the PS control signal S1 is inverted every time it jumps to the next track due to the track jump pulse S4, so O”.

As described above, according to this embodiment, even when skipping tracks to perform special playback, P is adjusted according to the playback track.
The S control signal S1 can be generated, and the recorded color difference signal components can be correctly restored.

In the embodiment of the present invention, as a method for removing crosstalk components from adjacent tracks, PS (Phase 5hift
) method, but it goes without saying that it is also possible to record color difference signal components of a constant phase on even-numbered tracks, and record on odd-numbered tracks by inverting the phase of the color difference signal components by 180 degrees for each IH.

(Effects of the Invention) As described above, the present invention provides a color difference between a color video signal between even-numbered tracks and odd-numbered tracks formed on a disc-shaped record carrier so that crosstalk components from adjacent tracks can be removed during reproduction. By recording the signal components in different phase forms and switching the phase form of the color difference signal components to be recorded using the rotation signal of the disc-shaped record carrier, it is possible to record correctly even when the address signal cannot be read. During playback, it is determined whether the track number is an even number or an odd number, and the processing of the color difference signal component is switched, and the processing of the color difference signal component is switched each time a track is skipped, so that the track numbers are changed between odd and even tracks as described above. It is now possible to stably reproduce even if the phase forms of the color difference signal components recorded on the
Since crosstalk interference of color difference signal components from adjacent tracks can be significantly reduced during reproduction, the recording density of the disk-shaped record carrier can be increased accordingly, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a recording block diagram of a color video signal recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the recording block diagram of FIG. 1, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a signal waveform diagram for explaining the reproduction block diagram of FIG. 3. 5...PS processing circuit, 6...ps control circuit,
17... Address signal reading circuit, 18... Even/odd discrimination circuit, 19... Rotation detection circuit.

Claims (3)

[Claims] (1) In a device that records a color video signal consisting of a luminance signal component and a color difference signal component on a disc-shaped record carrier in which a numbered guide groove is formed for each rotation, the number of the guide groove is an even number. A color video signal recording and reproducing apparatus characterized in that the phase form of the color difference signal component of the color video signal to be recorded is different between the case of 1 and the case of an odd number. (2) During recording, the rotation of the disc-shaped record carrier is detected, and the phase form of the color difference signal component to be recorded is switched every revolution based on the rotation signal. The color video signal recording and reproducing device according to item (1). (3) When reproducing a disc-shaped record carrier on which a color video signal is recorded, it is determined whether the number of the guide grooves formed on the disc-shaped record carrier is an even number or an odd number, and the color difference signal to be reproduced is determined. The color video signal recording and reproducing apparatus according to claim 1, characterized in that the processing of the reproduced color difference signal is switched every time the guide groove is skipped.