JPH02141079A - Video disk and its recording device - Google Patents

Abstract

PURPOSE:To increase the correlation of a recording signal and to decrease the deterioration of a reproduced picture quality due to crosstalk by linearly aligning address synchronizing signals in a radial direction on a track and recording them on the all tracks in an address area. CONSTITUTION:A video disk 1, which is obtained by linearly aligning the address synchronizing signals in the radial direction on the track and recording them on the all tracks in an address area 2 on a disk 1, is used, and video signals are recorded. In such a case, in the address area 2 formed on the disk 1, the address synchronizing signal is detected by a synchronization detecting circuit at every track from the reflected rays of recording laser rays in an (n) number, the position dislocation of the recording laser rays in the (n) number is obtained from a time difference, when the video signals are recorded, the time difference due to the position dislocation is corrected at every track, the positions of scanning lines on the track are made correspond, and the signals are recorded. Thus, the correlation of the recording signals between the tracks is increased, and the deterioration of the reproduced picture quality due to the crosstalk can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a video disc for recording video signals and a recording device thereof, and more particularly to a video disc and a recording device thereof for dividing a video signal into multiple channels and recording them in parallel. It is.

2. Description of the Related Art In general, a video signal is composed of a luminance signal and two types of color signals. When recording these video signals on a recording medium such as a VTR or an optical disk, there are methods of recording these signals by frequency division multiplexing and recording by time division multiplexing. When frequency-division multiplexing and recording is performed on a recording medium with non-linear recording/reproducing characteristics, there are problems such as moiré easily occurring in the reproduced signal. Furthermore, when recording by time division multiplexing, there is a drawback that the signal band becomes wider.

Therefore, it is known to apply a method of dividing the video signal into multiple channels and recording them in parallel.

On the other hand, when recording video signals on a recording medium such as a VTR or an optical disc, it is desirable to be able to record at high density. However, if the track pitch is narrowed in order to increase the recording density, crosstalk from adjacent tracks becomes a problem. To reduce the deterioration of playback quality due to crosstalk,
It is better if the correlation between signals recorded on adjacent tracks is strong. In video signals, adjacent scanning lines on the screen have a high correlation, but three types of signals on the same scanning line have a low correlation. Therefore, the video signal may be divided into multiple channels and recorded so that signals of the same type in nearby scanning lines appear on adjacent tracks on the screen. A conventional example of such a recording format is shown in FIG.

In FIG. 5, the luminance signal of the n-th scanning line is represented by Yn, the first color signal is represented by A, and the second color signal is represented by B7. The video signal shown in Figure (a) is compressed in the time axis of each color signal and time-division multiplexed onto the luminance signal, resulting in two channels (
The format when the data is divided into two parts (chi, ch2) is shown in [m(b)]. If these two channel signals are recorded on adjacent tracks, the signals of the same type from adjacent scanning lines on the screen will be lined up on the recording medium, which will increase the correlation between the recorded signals and reduce the deterioration of the reproduced image quality due to crosstalk. Reduced. Furthermore, since the space between two tracks can be narrower than the space between the tracks on both sides, the recording density can also be improved.

Problems to be Solved by the Invention As mentioned above, in order to effectively reduce deterioration in reproduced image quality, the positions of the scanning lines recorded on the two tracks must match. If this position is far away, a ghost-like disturbance will appear on the playback screen. In recent years, TV screens have become larger, and high-definition TVs have larger and wider screens. Moreover, since high-definition televisions have high-definition image quality and allow viewing from close to the screen, the tolerance for ghost-like deterioration becomes smaller. For example, on a 40-inch high-definition TV screen, the width is approximately 88 cm, and in order to reduce the ghost-like signal deviation to III+I11 or less,
The time lag of the crosstalk signal must be 33 ns or less. If the linear velocity of the recording medium is 10 m/s,
This time shift corresponds to a distance of 0.33 um on the recording medium. When using an optical disk as a recording medium, the position of the two-channel recording laser beam in the track direction is set to 0.3
Must be aligned within 3υm. Adjusting the positions of the two laser beams with such precision complicates the adjustment process. Furthermore, it is difficult to suppress fluctuations in the position of the laser beam due to environmental changes or aging of the optical head within this range, and the optical head also becomes expensive.

In addition, phase-change optical disks and magneto-optical disks, which are being developed as write-once/rewritable video disks, perform recording using the thermal energy generated when laser light is imprinted onto the disk. . The intensity distribution of the laser beam has a roughly Gaussian distribution, and even if a signal is recorded in the center, there are parts in the periphery where the intensity does not reach the recording temperature. Therefore, if the recording laser beams are aligned within the above range, the peripheral parts of the two fringed beams will overlap and the temperature between the tracks will increase, causing the shape of the recorded bit to change or the two bits to connect. .

The present invention has been made in view of the problems of the prior art, and is a video disc and a recording device thereof, which can compensate for the positional deviation of a recording laser beam and record with the scanning lines aligned on the track. is intended to provide.

Means for Solving the Problems The present invention provides a video disc having an address area in which address signals are recorded, and in which an address synchronization signal is sent to all tracks in the address area on the disc so that the positions on the tracks are arranged in a straight line in the radial direction. Use a video disc that has been recorded in advance and aligned.

an area detection circuit that detects the address area of the video disc; a synchronization detection circuit that irradiates n recording laser beams and detects an address synchronization signal for each track; and a synchronization detection circuit that detects an address synchronization signal for each track. Using a video disc recording device equipped with a timing detection circuit that measures the time difference and a timing correction circuit that corrects the time difference between each channel when recording the video signal, the video signal is divided into n channels, and the video signal is divided into n channels. Video signals are recorded on n tracks.

Operation According to the present invention, when a video signal is divided into n channels and recorded on 0 tracks of a surface recording disk, an address area is detected by an area detection circuit. In the address area, n recording laser beams are put into a reproduction state, and an address synchronization signal is detected for each track from the reflected light by a synchronization detection circuit.
By measuring the time difference between the address synchronization signals detected for each track using a timing detection circuit, the positional deviation of the n recording laser beams is determined. When the recording laser beam is put into the recording state after passing through the address area and a video signal is recorded, the timing correction circuit compensates for the time difference due to the positional deviation of the recording laser beam for each track by using a timing correction circuit. , it is possible to record by matching the positions of the scanning lines on the track.

Example Examples of the present invention will be described below.

FIG. 1 is a surface view of the video disc in this embodiment. In this embodiment, an address area 2 in which an address signal is recorded is provided in a part of the circumference of a track of a video disc 1. In this embodiment, there is one address area 2 as shown in the figure, but it is also possible to provide an address area for each sector on the opposite side of the circumference or by dividing the track into a plurality of sectors. Further, the address mark signal 3 is formed inside the track portion in advance of the address area in the disk rotation direction. FIG. 2 shows a format diagram of the address area in this embodiment. In this embodiment, a case will be described in which two tracks are used as a set. In Figure 2, one set of k-1st and 2nd, k+1+1st+2
Let the number be one set. When a plurality of tracks are used as a set, it is sufficient to record the address signal on one track in the set. In this embodiment, address signals are recorded in every other track, such as the kth and +2nd tracks. Since the address signal is recorded as a digital signal, the preamble signal and address synchronization signal are recorded in the address area in advance. In addition, in this embodiment, a preamble signal and an address synchronization signal are also sent to tracks where no address signal is recorded, such as the k-1st and +th tracks, so that the position on the track is linearly aligned in the radial direction with respect to other tracks. Align and record within the address area. Various signals within the address area are
For example, recording is performed by intermittent grooves for tracking control or by forming holes called pits on the track.

Next, a description will be given of an embodiment of a video disc recording apparatus for recording a video signal on a video disc on which an address sharing signal has been recorded in the address area as described above. In this embodiment, it is assumed that the video signal is divided into two channels and recorded on two tracks using two recording laser beams. FIG. 3 is a block diagram showing the configuration of a video disc recording apparatus according to an embodiment of the present invention. In FIG. 3, 10, 11.23 are photodetectors, 14.15 is a peer detection circuit, 17 is a timing detection circuit, and 26.27
is the video signal input terminal, 30.31 is the switching circuit, 33
is a timing correction circuit, 38 and 39 are FM modulation circuits,
40.41 is a laser drive circuit. The video disc used in this embodiment has, for example, intermittent grooves for tracking control in the address area as described above.
Signals such as address signals are recorded by forming holes called bits on the track.

Therefore, even if a video signal is recorded within the address area, its reproduction characteristics deteriorate. In this embodiment, a monitor light is irradiated onto the inner peripheral portion of the video disc, the light reflected from the disc is received by the photodetector 23, and the reproduced signal is sent to the preamplifier 2.
Amplify with 4. The area detection circuit 25 detects an address mark signal from the reproduced signal, and sends out a gate signal g corresponding to the address area. Laser drive circuit 40.4
1 lowers the power of the laser beam for inter-device recording of the gate signal g to neutralize the modulation. In addition, the address control time “#j
37 suspends reading of the memory 35, which will be described later, during the period of the gate signal g. In this way, the recording laser beam is brought into the reproduction state within the address area.

Further, the reflected light of the recording laser beam from the disk in the reproduction state is received by photodetectors 10 and 11 for each track, and the reproduced signal is amplified by preamplifiers 12 and 13. Address synchronization signals are detected from the reproduced signals of each channel by peer detection circuits 14 and 15. The detected address synchronization signals a and b for each track are input manually to the timing detection circuit 17. Furthermore, the reproduction signal and address synchronization signal of at least one channel are output to an address reproduction circuit 16 to reproduce the address signal. The timing detection circuit 17 includes a counter 20, registers 18 and 19, and a comparator 2.
Consists of 1. The counter 20 includes a clock generation circuit 22
The clock is counted from 1 to 1. Registers 18 and 19 write the values of the counter 20 at the time when address synchronization signals a and b are respectively input. Comparison circuit 2
1 is 11α written in register 18 and register 19
It compares the address synchronization signals and detects which address synchronization signal was reproduced earlier and outputs a switching signal C and a timing correction signal d. The recording laser beam of the channel that reproduced the address synchronization signal earlier will be located in front of the other recording laser beam. Therefore, by recording the recording signal of the later channel with a delay of the above-mentioned time difference, it is possible to record the recording signal aligned with the position recorded by the preceding channel.

Next, a case will be described in which the recording laser beam is put into the recording state after passing through the address area and a video signal is recorded.

The video signal that has been divided into two channels in advance is input to input terminal 2.
6. ．． Works manually from 27. The video signal of each channel,
The signal is amplified by amplifiers 28 and 29 and input to a switching circuit 30. The switching circuit 30 sends the video signal of the rear channel to the timing correction circuit 33 based on the switching signal C input from the timing detection@roguchi, and sends the video signal of the front channel as it is to the second switching circuit. Send on 31. The timing correction circuit 33
It is composed of a /D converter 34, a memory 35, a D/A converter 36, and an address control circuit 37. Timing correction circuit 33
The input video signal is converted into a digital signal by the A/D converter 34, and written into the memory 35 according to the write address from the address control circuit 37. The address control circuit 37 delays the read address by the address corresponding to the time difference between the two channels based on the timing correction signal d inputted from the timing detection circuit I7,
Read out the written video signal. The 0/A converter 36 is
The read video signal is converted into an analog signal and sent to the second switching circuit 31. The second switching circuit 31 converts the video signal directly input from the switching circuit 30 and the video signal input from the timing correction circuit 33tJ) to their original channels based on the switching signal C input from the timing detection circuit 7. The signal is switched and sent to the FM modulation circuits 38 and 39. Each FM modulation circuit 38.3
9 performs FM modulation on the video signal. Laser drive circuits 40 and 41 send out recording signals from output ends 42 and 43 for modulating the recording laser beams of the respective channels in accordance with the FM modulated video signal.

As described above, according to this embodiment, when recording a video signal, in the address area formed on the disk L, 2
Put the recording laser beams into a reproducing state, detect an address synchronization signal for each track from the reflected light using the same Jjl detection circuit, and measure the time difference between the address synchronization signals detected for each track using a timing detection circuit. The positional deviation of the two recording laser beams is determined by: When the recording laser beam is put into the recording state after passing through the address area and a video signal is recorded, the timing correction circuit compensates for the time difference due to the positional deviation of the recording laser beam for each track by using a timing correction circuit. , it is possible to record by matching the positions of the scanning lines on the track.

Generally, as a method of driving a disk, CLV is a method that controls the rotation speed so that the linear velocity is always constant.
) control method, and a CAV (CAV) control method in which the rotation speed is fixed so that the angular velocity is always constant.

In the CLV control method, the time difference corresponding to the positional shift between the two recording laser beams is constant on the disk. However, in the CAV control method, since the linear velocity changes, the time difference corresponding to the positional deviation of the two recording laser beams is not constant on the disk. Since the linear velocity V is proportional to the radius, the time difference due to positional deviation of the recording laser beam is inversely proportional to the radius. In this embodiment, the control method is used to record address synchronization signals on all tracks, detect the time difference corresponding to the positional deviation of the two recording laser beams for each track, and correct the recording start timing. Regardless of the situation, the positional deviation of the recording laser beam can always be corrected.

In this embodiment, a signal that has been divided into two channels in advance is used as the video signal, but it is also possible to configure the video disc recording apparatus to divide the signal into two channels. An embodiment of the video disc recording device in this case will be described. In this embodiment, similarly to the previous embodiment, the video signal is
It is assumed that the data is divided into channels and recorded on two tracks using two recording laser beams. FIG. 4 is a block diagram showing the configuration of a video disc recording device according to another embodiment of the present invention. In Figure 4, 10, 11
．． 23 is a photodetector, 12, 13.24 is a preamplifier, 1
4.15 is a synchronization detection circuit, 25 is an area detection circuit, 38
, 39 is an FM modulation circuit, and 40 and 41 are laser drive circuits, which are the same as the configuration shown in FIG. 3. Further, 44 is an input terminal for a video signal, 46 is an A/D converter, and 4
7 is a channel division circuit, 48.49 is a memory, 53
, 54 is a D converter, 50 is a write address control circuit, and 51.52 is a read address control circuit.

In this embodiment as well, a video disk similar to that of the previous embodiment is used, and the address mark signal is transmitted to the area detection circuit 2 in the same manner.
5, and by sending out a gate signal g corresponding to the address area, the recording laser beam is brought into a reproducing state within the address area.

In addition, in the same manner as in the above embodiment, the reflected light of the recording laser beam from the disk in the reproduction state is received by the photodetectors to and ti for each track, and an address synchronization signal is obtained from the reproduced signal of each channel. Detected by synchronization detection circuits 14 and 15. In this embodiment, the detected address synchronization signals a and b for each track are transmitted to the read address control circuit 51.5.
Output to 2.

Next, a case will be described in which the recording laser beam is put into the recording state after passing through the address area and a video signal is recorded.

A video signal is input manually from the input terminal 44.

The video signal is amplified by an amplifier 45 and converted to a digital signal by an A/D converter 46. The channel division circuit 47 is
Based on the switching signal from the write address control circuit 50, each scanning line is divided into two channels as shown in FIG.
9, the video signals are output by switching sequentially for each scanning line. The memories 48 and 49 write video signals in accordance with addresses from the write address control circuit 50. The read address control circuits 51 and 52 resynchronize address control when address synchronization signals a and b corresponding to the respective channels are input manually.

For example, when address synchronization corresponds to frame synchronization of a video signal, when the address synchronization signal is input manually, the read address is returned to the initial value of the frame.

When the stop period of the gate signal 8 ends, the read address control circuits 51 and 52 convert the time axis and transfer the video signal from the memory according to the resynchronized read addresses, as shown in FIG. 5(b). read out. D/A
Converters 53 and 54 convert the video signals read from the memory into analog signals. Each FM modulation circuit 38.39
performs FM modulation on the video signal. Laser drive circuits 40 and 41 send out recording signals from output ends 42 and 43 for modulating the recording laser beams of the respective channels in accordance with the FM modulated video signal.

As described above, according to this embodiment, when recording a video signal, two address areas are formed on the disk.
By putting the recording laser beams into the reproducing state, detecting an address synchronization signal for each track from the reflected light with a synchronization detection circuit, and synchronizing the read address of the memory for each channel with the detected address synchronization signal. Even if the two recording laser beams are misaligned, the recorded signals can be recorded with the same position on the track. Furthermore, according to this embodiment, it is possible to omit the timing detection circuit for determining the detection order and time difference of the detected address synchronization signals, and by correcting the memory read timing for each channel, the timing correction circuit can also be used. is possible.

In this embodiment, the address synchronization signal is used to detect the time difference due to the positional deviation of the recording laser beam, but the present invention is not limited to this, and it is also possible to use, for example, a sector mark signal.

Effects of the Invention As described above, according to the present invention, a video disc is used in which address synchronization signals are recorded in advance on all tracks within the address area on the disc with the positions on the tracks aligned linearly in the radial direction. When recording a signal, in the address area formed on the disk L, n recording laser beams are put into the reproduction state, and an address synchronization signal is detected for each track from the reflected light by a synchronization detection circuit. The positional deviation of n recording laser beams is determined from the time difference between the address synchronization signals detected for each track, and when the recording laser beam is set to the recording state after passing through the address area and the video signal is recorded, the recording laser beam for each track is The position of the scanning line on the track can be adjusted by correcting the timing of recording signals for each track using a timing correction circuit and by synchronizing the read address from the memory with the detected address synchronization signal. It is possible to match and record.

Furthermore, in the present invention, the address synchronization signal is recorded on all tracks, and the time difference corresponding to the positional deviation of n recording laser beams is detected for each track, and the recording start timing is corrected and shifted. Regardless of the control method of (1) or CLV, the positional deviation of the recording laser beam can always be corrected.

Therefore, the correlation between recorded signals between tracks becomes high, and deterioration in reproduced image quality due to crosstalk can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a surface diagram of a video disc according to an embodiment of the present invention, FIG. 2 is a format diagram of an address area in the same embodiment, and FIG. 3 is a configuration of a video disc recording device according to an embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of a video disc recording apparatus according to another embodiment of the present invention, and FIG. 5 is a schematic diagram showing a conventional example of a recording format. l; Video disk, 2 near address area, 25; Area detection circuit, 14, 15; Synchronization detection circuit, 17: Timing detection circuit, 33; Timing correction circuit, 48, 49; Memory, 51. 52; Read address control circuit . Name of agent: Patent attorney Shigetaka Awano (1 person) Figure 1, page 2-71174, or Figure 2

Claims (3)

[Claims] (1) A video disc on which a video signal is divided and recorded on n tracks (n is a natural number), and a video disc that has an address area in which an address signal is recorded on at least one track for each n track. A video disc characterized in that address synchronization signals are recorded on all tracks within an address area with the positions on the tracks linearly aligned in the radial direction. (2) A video disc recording device that divides a video signal into n channels (n is a natural number) and records the video signal by irradiating n recording laser beams onto n tracks,
An area detection circuit that detects the address area, a synchronization detection circuit that irradiates n recording laser beams and detects an address synchronization signal for each track, and measures the time difference between the address synchronization signals detected for each track. 1. A video disc recording device comprising: a timing detection circuit; and a timing correction circuit for correcting time differences between channels when recording a video signal. (3) A video disc recording device that divides a video signal into n channels (n is a natural number) and records the video signal by irradiating n recording laser beams onto n tracks,
A memory for storing video signals of each channel, an area detection circuit for detecting an address area, a synchronization detection circuit for emitting n recording laser beams and detecting an address synchronization signal for each track, and a synchronization detection circuit for each track. 1. A video disc recording device comprising: a read address control circuit that reads a video signal from the memory in synchronization with an address synchronization signal detected in the above.