JPS63187461A - Spindle servo equipment in information recoding disk reproducing device - Google Patents

Abstract

PURPOSE:To attain low cost by detecting a phase difference between a synchronizing signal included in a reproduced digital signal and reference signal at the time of pulling in a servo and applying the drive control of a spindle motor based on the phase difference so as to eliminate a frequency generator and its relevant circuit. CONSTITUTION:The frequency of a reference clock generated from a reference clock generator 43 in a digital information demodulation system is constant and the spindle servo is applied based on the phase difference between a frequency division signal of a fixed reference clock and a frequency division signal of a frame synchronizing signal. That is, in case of the reproduction, the phase difference between the synchronizing signal included in the reproduced digital signal and the reference signal is detected to pull in the spindle servo based on the phase difference. Since the frequency generator and its relevant circuit are omitted, the low cost is attained.

Description

Detailed Description of the Invention Technical Field The present invention relates to a spindle servo device in an information recording disk reproducing device, and in particular to an information recording disk (hereinafter simply referred to as a disk) on which a video signal subjected to frequency modulation processing and a predetermined digital signal are multiplex recorded. This invention relates to a spindle servo device in an apparatus capable of regenerating (referred to as ``1'').

BACKGROUND ART As a disc on which a video signal subjected to frequency modulation processing and a predetermined digital signal are multiplexed, a so-called CD (Compact
2. Description of the Related Art Hi-Fi video discs are known that record digital audio signals in the disc format.

In a playback device that plays back such Hi-Fi video discs, the spindle servo, which controls the rotation of the spindle motor that drives the disc, synchronizes the horizontal synchronization signal contained in the playback video signal with the basic horizontal synchronization signal in the servo-locked state. However, since the lock range of this servo is narrow, about ±10% with respect to the lock point (target rotation speed) (see Figure 2 (a)), during so-called rough servo An operation is performed to pull the rotational speed of the spindle motor into a lock range based on the output of a frequency generator (FC) interlocked with the spindle motor.

In this way, in the conventional device, the lock range of the spindle servo based on the reproduced horizontal synchronization signal is narrow, and a frequency generator and associated circuit are required to pull in the servo, which hinders the cost reduction of the device. It became.

Furthermore, as shown in FIG. 3, a disc on which a video signal subjected to frequency modulation processing and a predetermined digital signal are multiplexed is the same size as a compact disc, and audio information is recorded using PCM (Pulse Code Motion Control).
The first area (hereinafter referred to as CD 8.El area) 1a on the inner side where the frequency modulated video signal and the PCM audio signal are multiplex recorded. Discs (hereinafter referred to as composite discs) in which information is recorded in a second area on the side (hereinafter referred to as video area) lb are being developed; Regarding the spindle servo during playback, the above-mentioned H
The same is true for i-Fi video discs.

Summary of the Invention The present invention has been made in view of the above-mentioned points, and provides a spindle for an information recording disk reproducing device that enables cost reduction by eliminating the need for a conventionally used frequency generator and associated circuit. The purpose is to provide servo devices.

A spindle servo device according to the present invention is an information recording disk reproducing device having an area in which a video signal subjected to frequency modulation processing and a predetermined digital signal are multiplexed in at least a portion in the radial direction. , a force phase difference between a synchronization signal and a reference signal included in a reproduced digital signal is detected, and the rotation of the spindle motor is controlled based on this phase difference.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing the configuration of a reproducing apparatus capable of reproducing, for example, a composite disc, which is equipped with a spindle servo device according to the present invention. This reproducing apparatus is configured to be capable of reproducing compact discs. A disc 1 is rotationally driven by a spindle motor 2, and recorded information is read by an optical pickup 3. The pickup 3 includes a laser diode as a light source, an optical system including an objective lens, a photodetector that receives reflected light from the disk 1, a focus actuator that controls the position of the objective lens with respect to the information recording surface of the disk 1, and a pickup. A tracking actuator and the like that control the position of the laser spot emitted from 3 in the disk radial direction with respect to the recording track are built-in. The read output of the pickup 3 is sent to the digital information demodulation system 4.
and a video information demodulation system 5, respectively.

The digital information demodulation system 4 is provided with a changeover switch 40 that changes depending on the playback area (CD area and video area) during playback of a composite disc. When the video area is reproduced, it is on the b side, and switching is performed in response to a switching command issued from a system controller 6, which will be described later.

The PCM audio signal recorded in the CD area and the video area is, for example, EFM (Eight to Fo
urteenModulaLIon) signal, CD
When reproducing a region, the reproduced EFM signal, which is the read output of the pickup 3, is directly supplied to the demodulation/correction circuit 41 via the changeover switch 40. On the other hand, when reproducing the video area, a reproduced E F M signal extracted from the read output of the pickup 3 by the E F M extraction circuit 42 is supplied to the demodulation/correction circuit 41 via the changeover switch 40 .

The demodulation/correction circuit 41 demodulates the EFM signal into R
In addition to writing to a memory (not shown) such as an AM (random access memory), it also controls RAM based on the reference clock from the reference clock generator 43, exchanges data, and performs deinterleaving and processing of the data. Error correction is performed using the included parity. The digital audio signal demodulated and corrected by the demodulation/correction circuit 41 is processed by the audio signal processing circuit 44, which includes a D/A (digital/analog) converter, a deglitcher, etc., and then sent to the left and right channel audio output terminals. Supplied to 7L and 7R.

The reference clock from the reference clock generator 43 is sent to the frequency divider 4.
5 and is also supplied to the spindle error signal generation circuit 46, where the frame synchronization signal is separated and extracted from the reproduced EFM signal by the synchronization separation circuit 47 and divided by the frequency divider 48. A frequency error and a phase error with respect to the frequency-divided signal are detected, and a spindle error signal (control signal) corresponding to these errors is generated. This spindle error signal becomes the sole power of the spindle control switching circuit 8. The reference clock generator 43 has a precision servo (servo lock) on the a side when playing the CD area and a rough servo (servo unlock) on the video area, and a precision servo (servo lock) on the video area in response to a switching command issued from the system controller 6.
A DC voltage E or a frame synchronization signal is applied via the changeover switch 49 which switches to the b side at different times, so that the reference clock generator 43 changes the frequency according to the DC voltage E during playback of the CD area and rough servo in the video area. It generates a fixed reference clock, and during precision servo in the video domain, it generates a reference clock synchronized with a frame synchronization signal.

On the other hand, in the video information demodulation system 5, an RF (high frequency) signal is extracted from the read output of the pickup 3 obtained during reproduction of the video area by an RF extraction circuit 50, demodulated into a video signal by a video demodulation circuit 51, and then It is supplied to the axis correction circuit 52.

For example, the time axis correction circuit 52 controls the CCD according to the phase difference between the reference horizontal synchronization signal, which is the oscillation output of the fixed oscillator 53, and the horizontal synchronization signal and color burst signal in the video signal.
The configuration is such that time axis correction is performed by changing the delay amount of variable delay elements such as. The video signal subjected to time axis correction by the time axis correction circuit 52 is supplied to the video output terminal 9 via the video signal processing circuit 54.

The video signal processing circuit 54 performs processing such as video muting for inhibiting output of the video signal and character insertion.

The basic horizontal synchronization signal output from the fixed oscillator 53 is also supplied to the spindle error signal generation circuit 55, and in this circuit 55, the position of the reproduced horizontal synchronization signal separated and extracted from the video signal by the synchronization separation circuit 56 is determined. A phase difference is detected, and a spindle error signal corresponding to this phase difference is generated. This spindle error signal serves as an input to the spindle control switching circuit 8. The spindle error signal selected by the spindle control switching circuit 8 is supplied to a spindle drive circuit 11 that drives and controls the spindle motor 2.

A position detector 10 for detecting the moving position of the laser spot emitted from the pickup 3 in the disk radial direction is provided near the moving path of the pickup 3 in the disk radial direction. The information is provided to the system controller 6.

Based on this position information, it is possible to detect that the laser spot has arrived near the boundary between the CD area and the video area. The system controller 6 is composed of a microcomputer, and exchanges data with various parts such as the digital information demodulation system 4 and the video information demodulation system 5, and controls the changeover switch 40 in the digital information demodulation system 4.
．． 49, a switching command to the spindle control switching circuit 8, etc.

Next, the reproduction operation of the reproduction apparatus having such a configuration will be explained. It is assumed that disc type information indicating that the disc is a composite disc is recorded in the lead-in area of the composite disc.

First, when playing a disc, the system controller 6
If disc type information is included in the read output from the lead-in area, it is determined that the disc is being played back or a composite disc, and if it is not included, it is determined that it is a compact disc.

When playing a compact disc, selector switch 4
0.49 are both held on the a side until the end of reproduction, and the spindle control switching circuit 8 supplies the spindle error signal from the digital information demodulation system 4 to the spindle drive circuit 11. That is, the frequency of the reference clock generated from the reference clock generator 43 in the digital information demodulation system 4 is constant, and the spindle servo adjusts to the phase difference between the frequency division signal of this fixed reference clock and the frequency division signal of the frame synchronization signal. It is done based on this. Since the dimensions of the compact disc playback operation are well known, their explanation will be omitted here.

On the other hand, when reproducing a composite disc, when reproducing a CD area, the same operation as when reproducing a compact disc is performed.

Of course, the same applies to the spindle servo.

When the playback area shifts to the video area, the system controller 6 detects this based on the position information from the position detector 10, switches the changeover switch 40 to side b, and rotates the spindle motor 2 to the maximum specified rotation in the video area. Control to accelerate towards speed. At this time,
The spindle servo is unlocked, and the servo is pulled in at this time based on the phase difference between the frequency division signal of the fixed reference clock and the frequency division signal of the reproduction frame synchronization signal because the changeover switch 49 is on the a side. It will be done.

The capture range of the servo using this playback frame synchronization signal is very wide, about 1/3 to 3 times the rotation speed of the lock point (see Figure 2 (b)), and up to this rotation speed it is not possible to start up by time management. It can be pulled in with sufficient stability.

When the rotational speed of the spindle motor 2 falls within the lock range, a lock detection signal is generated from the spindle error signal generation circuit 46, and in response to this lock detection signal, the system controller 6 switches the changeover switch 49 to the b side, and The spindle control switching circuit 8 is controlled to select the spindle error signal from the video information demodulation system 5. As a result, during playback of the video area, precision servoing of the spindle motor 2 after servo lock is performed based on the phase difference between the playback horizontal synchronization signal detected by the video information demodulation system 5 and the reference horizontal synchronization signal. become. Further, in the digital information demodulation system 4, a reference clock generator 43 generates a reference clock synchronized with the reproduced frame synchronization signal, and processing such as error correction is performed in the demodulation/correction circuit 41 based on this reference clock.

In this way, when starting up in the video area, the playback E
By performing servo pull-in based on the phase difference between the reproduced frame synchronization signal included in the FM signal and the reference clock, the conventionally used frequency generator and associated circuit can be omitted. In addition, as shown in Figure 2, the lock range of servo (b) based on the playback frame synchronization signal included in the playback EFM signal is ±5% with respect to the target rotation speed, and the playback horizontal synchronization signal included in the playback video signal. Since the capture range of the signal-based servo (a) is narrower, the above-mentioned servo switching is performed smoothly.

In the above embodiment, after the servo is locked, the servo is switched and control is performed using the spindle error signal detected by the video information demodulation system 5, but in FIG. The oscillator 53 in the video information demodulation system 5, which serves as a generator, is depicted as oscillating in synchronization with the reproduction horizontal synchronization signal as shown by the broken line in the figure, and the reproduction frame synchronization included in the reproduction EFM signal is achieved regardless of the reproduction area. It is also possible to perform spindle control based on the phase difference between the signal and the reference clock. According to this, even if the color television format of the video information is different, the CD format is common, so the audio Information can be reliably reproduced,
Also, video information can be played back, albeit in black and white.

In addition, in the above embodiment, a case was explained in which the application was applied at startup in the video area of a composite disc, but Hi-F
It can be applied to all digital compatible discs such as i-Video discs, and can be applied not only to servo retraction at startup, but also to servo retraction after the spindle servo is unlocked when searching for a CLV disc, for example. be.

As described in detail, according to the present invention, composite discs and H
When playing a digital compatible disc such as an i-Fi video disc, the synchronization signal included in the playback digital signal and 2! By detecting the phase difference with the quasi-signal and pulling in the spindle servo based on this phase difference, it is possible to omit the conventionally used frequency generator and associated circuits, resulting in cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a playback device (where I indicates the configuration), which is equipped with a spindle servo device according to the present invention and is capable of playing back a composite disc, for example. FIG. 2 is a diagram showing the relationship between the spindle rotation speed and the capture range. , Fig. 3 is a diagram showing the division of the recording area of the composite disc. Explanation of the symbols of the main parts

Claims (1)

[Claims] A spindle servo device in a playback device for playing back an information recording disk having an area in which a video signal subjected to frequency modulation processing and a predetermined digital signal are multiplexed in at least a portion in a radial direction, the spindle servo device including a playback digital signal in the playback digital signal. A means for detecting a phase difference between a included synchronization signal and a reference signal and generating a control signal according to this phase difference, and controlling the rotation of the spindle motor based on the control signal at least when the servo is retracted. A spindle servo device in an information recording disk reproducing device characterized by: