JP2551571B2 - Information recording disk playback device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording disk reproducing apparatus, and more particularly to an information recording disk (hereinafter, simply referred to as a disk) in which a frequency-modulated video signal and a predetermined digital signal are multiplexed and recorded. The present invention relates to a reproducible information recording disc reproducing apparatus.

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

In a playback device that plays back such a Hi-Fi video disc, the spindle servo that controls the rotation of the spindle motor that drives the disc, in the servo-locked state, has a horizontal sync signal and a reference horizontal sync signal that are included in the playback video signal. Although it is performed based on the phase difference, the lock range of this servo is as narrow as ± 10% of the lock point (target rotation speed) (see Fig. 2 (a)), so the spindle motor is used during so-called rough servo. Based on the output of the linked frequency generator (FG), the rotation speed of the spindle motor is pulled within the lock range.

Thus, in the conventional device, the lock range of the spindle servo based on the reproduction horizontal synchronization signal is narrow,
Since a frequency generator and a circuit associated therewith are required for pulling in the servo, it has been an obstacle to cost reduction of the device.

Also, as shown in FIG. 3, a disc on which a frequency-modulated video signal and a predetermined digital signal are recorded in multiplex has the same size as a compact disc, for example, audio information is converted into PCM (Pulse Code Modulation). The first area on the inner circumference side (hereinafter referred to as a CD area) 1a, which is recorded as follows, and the second area on the outer circumference side, on which the video signal subjected to frequency modulation processing and the PCM-converted audio signal are multiplexed and recorded ( Hereinafter, a disc (hereinafter referred to as a composite disc) in which information is recorded by dividing the region into a video region) and a 1b is being developed. Regarding the spindle servo at the time of reproducing the video region of the composite disc, The same thing can be said as in the case of the Hi-Fi video disc described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides an information recording disk reproducing apparatus capable of cost reduction by eliminating the conventionally used frequency generator and its accompanying circuit. The purpose is to do.

An information recording disk reproducing apparatus according to the present invention provides a reproduction video signal and a reproduction digital signal based on a read signal read from an information recording disk having an area where at least a part of a video signal and a predetermined digital signal are multiplexed and recorded. An information recording disk reproducing apparatus for obtaining, wherein EFM extracting means for extracting an EFM signal from the read signal to obtain a reproduced EFM signal, and first synchronous separation for separating and extracting a first synchronous signal from the reproduced EFM signal Means, a demodulation correction means for outputting a signal obtained by performing EFM demodulation of the reproduced EFM signal as the reproduced digital signal, the signal being error-corrected according to a reference clock signal, and a clock of a predetermined fixed frequency during coarse adjustment servo A signal is generated as the reference clock signal, while a clock signal synchronized with the first synchronization signal is used as the reference during fine adjustment servo. Reference clock generating means for generating as a lock signal, video demodulating means for demodulating the read signal to obtain the reproduced video signal, and second synchronous separating means for separating and extracting a second synchronous signal from the reproduced video signal, A spindle servo circuit for controlling the rotation speed of the spindle motor based on the first synchronization signal during the rough adjustment servo, and a rotation speed control for the spindle motor based on the second synchronization signal during the fine adjustment servo. It is characterized by that.

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the structure of an information recording disk reproducing apparatus according to the present invention.

In such an information recording disc reproducing apparatus, not only the composite disc but also the recorded information of the compact disc can be reproduced. The disk 1 is rotationally driven by the spindle motor 2, and the recorded information is read by the 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 disc 1, a focus actuator that controls the position of the objective lens with respect to the information recording surface of the disc 1, and a pickup. A tracking actuator and the like for controlling the position of the laser spot emitted from the disk 3 in the disk radial direction with respect to the recording track are built in. The read output of the pickup 3 is supplied to a 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 switches according to the reproduction area (CD area and video area) when reproducing the composite disc. This changeover switch 40 is on the a side when reproducing the CD area, When the video area is reproduced, it is on the side b, and its switching is performed in response to a switching command issued from the system controller 6 described later.
The PCM audio signal recorded in the CD area and the video area is, for example, an EFM (Eight to Fourteen Modulation) signal, and when reproducing the CD area, the reproduced EFM signal which is the read output of the pickup 3 is directly demodulated via the changeover switch 40. It is supplied to the correction circuit 41. On the other hand, during reproduction of the video area, the reproduced EFM signal extracted by the EFM extraction circuit 42 from the read output of the pickup 3 is supplied to the demodulation / correction circuit 41 via the changeover switch 40.

The demodulation / correction circuit 41 EFM demodulates the EFM signal and writes it in a memory (not shown) such as a RAM (random access memory), and controls the RAM based on the reference clock from the reference clock generator 43. , Data is exchanged, and error correction is performed using the de-interleave and the parity included in the data. The digital audio signals demodulated and corrected by the demodulation / correction circuit 41 are processed by an audio signal processing circuit 44 including a D / A (digital / analog) converter and a deglitcher, and then left and right channel audio output terminals. 7
Supplied to L and 7R.

The reference clock from the reference clock generator 43 is the frequency divider 45.
The frequency is divided by and is also supplied to the spindle error signal generation circuit 46. In the circuit 46, the reproduction EFM is performed by the sync separation circuit 47.
A frequency error and a phase error between the frame sync signal separated and extracted from the signal and divided by the frequency divider 48 with the divided signal are detected, and a spindle error signal (control signal) corresponding to these errors is generated. It This spindle error signal becomes one input of the spindle control switching circuit 8. The reference clock generator 43 responds to a switching command issued from the system controller 6 to rough servo (servo unlock) in the CD area during reproduction and in the video area, that is, during coarse adjustment servo, to the a side and precise in the video area. Servo (servo lock), that is, during fine adjustment servo, the DC voltage E or the frame synchronization signal is applied via the changeover switch 49 that switches to the b side, thereby the reference clock generator.
The reference numeral 43 generates a fixed reference clock having a frequency corresponding to the DC voltage E during reproduction in the CD area and during rough servo in the video area, and generates a reference clock synchronized with the frame synchronization signal during precision servo in the video area.

On the other hand, in the video information demodulation system 5, an RF (high frequency) signal is extracted by the RF extraction circuit 50 from the read output of the pickup 3 obtained during reproduction of the video area, and the video demodulation circuit 51.
The signal is demodulated into a video signal and then supplied to the time axis correction circuit 52. The time axis correction circuit 52 is, for example, a fixed oscillator.
A configuration in which time axis correction is performed by changing the delay amount of a variable delay element such as a CCD in accordance with the phase difference between the reference horizontal synchronization signal that is the oscillation output of 53 and the horizontal synchronization signal and color burst signal in the video signal. Has become. The video signal whose time axis has been corrected 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 mute for inhibiting the output of the video signal and character insertion.

The reference horizontal synchronization signal output from the fixed oscillator 53 is also supplied to the spindle error signal generation circuit 55, and the circuit 55
At, the sync separation circuit 56 detects a phase difference from the reproduced horizontal sync signal separated / extracted from the video signal, and a spindle error signal corresponding to this phase difference is generated. This spindle error signal becomes the other input of the spindle control switching circuit 8. The spindle error signal selected by the spindle control switching circuit 8 is supplied to the spindle drive circuit 11 which controls the drive of the spindle motor 2.

A position detector 10 for detecting the movement position of the laser spot emitted from the pickup 3 in the disc radial direction is provided near the movement path of the pickup 3 in the disc radial direction. The position detected by the position detector 10 is provided. Information is supplied to the system controller 6. Based on this position information, it can be detected 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 generates switching commands for the changeover switches 40 and 49 in the digital information demodulation system 4. , And issues a switching command to the spindle control switching circuit 8.

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

First, when playing a disc, the system controller 6 determines that the disc being played is a composite disc if the disc type information is included in the read output from the lead-in area, and the compact disc if it is not included. Judge as a disk.

Selector switch when playing a compact disc
Both 40 and 49 are held on the side a 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 determines the phase difference between the divided signal of the fixed reference clock and the divided signal of the frame synchronization signal. It is done based on. Since the reproducing operation of the compact disc is well known, its explanation is omitted here.

On the other hand, when reproducing a composite disc, when reproducing the CD area, reproduction is performed by the same operation as when reproducing the compact disc. 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, and the changeover switch
While switching 40 to the b side, the spindle motor 2 is controlled to accelerate toward the maximum specified rotation speed in the video area. At this time, the spindle servo is unlocked, and the servo pull-in at this time is due to the phase difference between the frequency-divided signal of the fixed reference clock and the frequency-divided signal of the reproduction frame synchronization signal because the changeover switch 49 is on the a side. It is carried out based on. The servo capture range based on this playback frame synchronization signal is 1/3 of the rotation speed of the lock point.
It is very wide, about 3 times (see FIG. 2 (b)), and it is possible to pull in sufficiently stably up to this number of revolutions by starting up by time management.

When the rotation 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 the system controller 6 switches the changeover switch 49 to the b side in response to this lock detection signal. The spindle control switching circuit 8 is controlled to select the spindle error signal from the video information demodulation system 5.
Accordingly, during reproduction of the video area, the precision servo of the spindle motor 2 after the servo lock is performed based on the phase difference between the reproduction horizontal synchronizing signal detected by the video information demodulation system 5 and the reference horizontal synchronizing signal. become. Further, in the digital information demodulation system 4, the reference clock generator 43 generates a reference clock synchronized with the reproduction frame synchronizing signal, and the demodulation / correction circuit 41 performs processing such as error correction based on the reference clock.

In this way, when starting up in the video area, playback
By performing the servo pull-in based on the phase difference between the reproduction frame synchronization signal included in the EFM signal and the reference clock, it is possible to omit the conventionally used frequency generator and its accompanying circuit. Further, as shown in FIG. 2, the lock range of the servo (b) by the reproduction frame synchronization signal included in the reproduction EFM signal is ± 5% with respect to the target rotation speed and the reproduction horizontal synchronization included in the reproduction video signal. Since it is narrower than the capture range of the servo (a) by the signal, the above-mentioned servo switching is smoothly performed.

In the above embodiment, after the servo lock, the servo is switched and the control is performed by the spindle error signal detected by the video information demodulation system 5. However, in FIG. 1, the reference clock generator 43 is fixed to the fixed reference clock. As a generator, the oscillator 53 in the video information demodulation system 5 is configured to oscillate in synchronism with the reproduction horizontal synchronization signal as shown by the broken line in the figure, and the reproduction frame synchronization signal included in the reproduction EFM signal regardless of the reproduction area. It is also possible to perform spindle control based on the phase difference between the audio information and the reference clock. According to this, even if the color television system of video information is different, the CD format is common, so the audio information Can be reliably played back, and the video information can be played back in black and white.

Further, in the above-mentioned embodiment, the case where the invention is applied at the start-up in the video area of the composite disc is explained.
It can be applied to all digital discs such as video discs, and can be applied not only to the servo pull-in at startup but also to the servo pull-in after the spindle servo is unlocked, for example, during CLV disc search. .

As described above, according to the present invention, when reproducing a digital disc such as a composite disc or a Hi-Fi video disc, the phase difference between the synchronization signal and the reference signal contained in the reproduced digital signal is determined. By detecting and pulling in the spindle servo based on this phase difference, the conventionally used frequency generator and the circuit associated therewith can be omitted, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the structure of a reproducing apparatus capable of reproducing a composite disc according to the present invention, FIG. 2 is a diagram showing the relationship between the spindle rotation speed and the capture range, and FIG. 3 is a recording area of the composite disc. It is a figure which shows a division. Description of symbols of main parts 1 ... Disk, 2 ... Spindle motor 3 ... Optical pickup 4 ... Digital information demodulation system 5 ... Video information demodulation system 8 ... Spindle control switching circuit

Front page continuation (72) Inventor Takeshi Izumo 4-2610 Hanazono, Tokorozawa City Pioneer Co., Ltd. Tokorozawa Plant (72) Inventor Chira Takeya Tokorozawa 4-2610 Flower Garden Pioneer Co., Ltd. Tokorozawa Plant (72) Inventor Katakami Kazuhiko 426-10 Hanazono, Tokorozawa City Pioneer Co., Ltd. Tokorozawa Plant (56) Reference JP-A-60-62889 (JP, A) JP-A-59-71164 (JP, A) JP-A-63-167472 (JP, JP, A) A)

Claims (1)

(57) [Claims] 1. An information recording disk reproduction for obtaining a reproduction video signal and a reproduction digital signal respectively on the basis of a read signal read from an information recording disk having an area in which at least a part of a video signal and a predetermined digital signal are multiplex-recorded. An apparatus for extracting an EFM signal from the read signal to obtain a reproduced EFM signal; a first sync separation means for separating and extracting a first sync signal from the reproduced EFM signal; Demodulation and correction means for outputting a signal obtained by performing EFM demodulation of the EFM signal according to the reference clock signal as the reproduced digital signal, and a clock signal of a predetermined fixed frequency during the coarse adjustment servo. While being generated as a signal, a clock signal synchronized with the first synchronization signal is generated as the reference clock signal during fine adjustment servo. Reference clock generation means, video demodulation means for demodulating the read signal to obtain the reproduction video signal, second synchronization separation means for separating and extracting a second synchronization signal from the reproduction video signal, and during the coarse adjustment servo A spindle servo circuit for controlling the rotation speed of the spindle motor based on the first synchronization signal, and for controlling the rotation speed of the spindle motor based on the second synchronization signal during the fine adjustment servo. Information recording disk reproducing device.