JPH0729301A - Recording device for optical disk - Google Patents

Abstract

PURPOSE:To obtain a reproduced signal having jitter to the same extent as that of a reproducing only disk by correcting jitter generated in recording as to a signal recorded in synchronism with an ATIP code already recorded on an optical disk. CONSTITUTION:A video signal (d) outputted form a recording signal generating circuit 13 is inputted to a Time Base Corrector(TBC) 10 being a recording mode, after it is made a signal synchronized with an ATIP code already recorded on an optical disk 1, converted to a PFM signal by a forming circuit 11. This signal drives a semiconductor laser incorporated in a pickup 3 and recorded. In reproducing mode, a reproduced video signal (g) is converted to a digital signal by the TBC 10, and written in a memory, read out of the memory by the standard signal (k) and converted to an analog signal, and a reproduced video signal (i) in which jitter is corrected. Consequently, jitter generated in recording and reproducing can be corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recordable optical disk recording apparatus.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to the block diagram of FIG. A method of recording a video signal with the write-once optical disc apparatus is as follows: FM is applied to a recording video signal d obtained by adding audio and control signals to the video signal from the recording signal processing circuit 13.
The modulation / waveform shaping circuit 11 converts the PFM signal c. The semiconductor laser mounted on the pickup 3 is driven by this PFM signal c to record a signal on the optical disc 1.

The difference between the write-once type laser disk device and the read-only laser disk device is that the read-only laser disk device performs tracking servo and spindle servo by the presence or absence of recording pits and the video synchronization signal recorded on the optical disk. It is that you are. In the write-once type laser disk device, since there is no signal serving as a reference for the tracking servo and spindle servo of the optical disk, a pregroove is recorded on the optical disk in advance, and the tracking servo is applied by this pregroove.

A pregroove can be obtained by wobbling in the direction perpendicular to the track direction, recording an ATIP code on the wobbling, and decoding the ATIP code.
Spindle servo is applied by TIP clock j. When reproducing, the same operation as in a normal laser disk device is performed. The RF signal g reproduced from the optical disc is demodulated into a reproduced video signal h by the RF equalizer / FM demodulation circuit 12, and after the time axis fluctuation component is corrected by the TBC 10, it is inputted to the reproduced signal processing circuit 14 to obtain reproduced video / audio. ing.

[0005]

The main problem that occurs when reproducing the signals recorded on these optical disks is the time-axis fluctuation component of the reproduced signals, that is, the jitter. Of these jitters, those caused by the optical disk are eccentricity of the optical disk, meandering of the track due to distortion of the track, and fluctuations due to rotational fluctuations / vibrations of the recording device. The element can be ignored. The rotation speed frequency on the groove of the optical disc at this time is expressed by the following equation.

Ftach = (ωN / 2π)  (1 + 2 (Δr
/ R) sinωt) where R = radius from center of groove ftach = rotation frequency on groove ω = angular velocity of axis t = time Δr = distance between center of groove and center of rotation

However, in a recordable optical disk, the above-mentioned jitter occurs during recording due to the difference between the center of the pre-groove and the center of rotation for obtaining the tracking servo error signal. In other words, in a recordable optical disc, the elements that were ignored in the read-only disc will also occur. When such a recording signal c is recorded on the optical disc as it is, since the recording signal c and the ATIP code on the optical disc are not synchronized, the jitter component with the optical disc generated at the time of recording is added to the recording signal as it is and generated at the time of reproduction. Overlapping with the jitter component causes larger jitter than that of a read-only optical disc.

[0008]

ATI pre-recorded for use in rotation control of a recordable optical disc, etc.
The P code and the TBC circuit for jitter correction are used to record the record information signal in synchronization with this signal. Normal TB
The C circuit uses the clock synchronized with the time information signal such as the horizontal synchronization signal of the video recorded on the optical disc to drive the TB circuit.
The time axis is corrected by writing in the memory in the C circuit and reading it out with a reference clock such as a crystal oscillator. Here, at the time of recording, writing is performed with the reference clock, and the ATI
The ATIP clock obtained when P is decoded is read and recorded on the optical disc.

[0009]

In this way, the ATIP already on the optical disk is
Since the signal recorded in synchronization with the code can correct the jitter generated at the time of recording, it is possible to obtain a reproduction signal having the same jitter as that of the reproduction-only disc.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the block diagram of FIG. Since FIG. 1 is compared with FIG. 3, the basic configuration such as the control of the pickup and the control of the spindle motor is the same as that of the conventional example, and the description thereof will be omitted.

The video signal d output from the recording signal generation circuit 13 is input to the TBC 10 in the recording mode,
After the signal e synchronized with the ATIP code previously recorded on the optical disc 1 is formed, the FM modulation / waveform shaping circuit 1
It is converted into a PFM signal c by 1. This PFM signal c
Drives a semiconductor laser mounted on the pickup 3 to record a signal. Tracking servo at this time,
The control system of the spindle servo is performed in the same manner as the conventional technique.

Next, the TBC operation will be described with reference to FIG.
The ATIP clock j extracted by the ATIP decoder 8 is multiplied by the frequency multiplication circuit (PLL) 15 of the TBC 10 to the sampling frequency q of the video signal.
In the TBC recording mode, the reference signal k is used as a write clock for the A / D converter 22 and the memory 21, and the sampling signal q is used as a read clock for the D / A converter 20 and the FIFO memory 21. Therefore, the video signal d is A / D converted by the reference signal k and written to the memory 21, and read from the memory 21 by the sampling signal q to be D / D converted.
A conversion is performed to obtain a signal synchronized with ATIP.

In the reproduction mode, on the contrary, the sampling signal q is used as the write clock of the A / D converter 22 and the memory 21, and the reference signal k is used as the read clock of the D / A converter 20 and the memory 21. Therefore, the reproduced video signal g is A / D converted by the sampling signal q and written in the memory 21, read from the memory 21 by the reference signal k, and D / A converted to obtain the reproduced video signal i in which the jitter is corrected. Switches between these modes
By performing the processing according to No. 19, it is possible to correct the jitter generated during recording / reproduction without changing the basic configuration of the TBC.

[0014]

According to the present invention, since the jitter at the time of recording can be reduced, the reproduction jitter is about the same as that of the read-only optical disk, and the reproduction can be performed without increasing the mechanical accuracy of the optical disk and the capacity of the TBC memory. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an embodiment of the TBC circuit in FIG.

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols] 1 optical disk 2 spindle motor 3 pick-up 4 laser controller 5 preamplifier 6 pickup each servo 7 spindle servo 8 ATI
P decoder 9 Reference crystal oscillator 10 TBC
Circuit 11 FM modulation, waveform shaping circuit 12 RF
Equalizer, FM demodulation 13 Recording signal processing circuit 14 Reproduction signal processing circuit 15 PLL circuit 16 to 19 Switch 20 D / A converter 21 FI
FO memory 22 A / D converter a laser b laser diode drive signal c PFM signal d video signal e synchronization signal f RF signal g replay video signal i replay video signal j ATIP clock k reference signal l servo error signal m pickup servo drive Signal n Spindle drive signal p Mode switching signal q Sampling signal r Write clock s Read clock t Spindle reference signal

Claims (1)

[Claims] 1. A device for recording on a recordable optical disc, comprising a Time Base Corrector (hereinafter abbreviated as TBC) for correcting a time base when reproducing an analog signal, for recording a signal on the optical disc. An ATIP decoder for reproducing the ATIP code that is the reference of the above and extracting the clock of the reproduced ATIP code is provided, and the time axis fluctuation (jitter) generated at the time of recording is reduced by using this ATIP clock and the TBC circuit. Optical disk recording device.