JPH10241281A - Optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adaptively control a disk reproducing speed based on correction information obtained during the reproduction of an optical disk by producing a control voltage proportional to an error correction amount, causing oscillation by an oscillation frequency proportional to this control voltage and supplying the reference clock of the oscillation frequency to a signal processing circuit. SOLUTION: In an optical disk reproducing device 11, a reading signal containing the digital data and the synchronous signal of an optical disk 2 is supplied to a signal processing circuit 5. The signal processing circuit 5 produces a correction error amount signal proportional to a correction error amount during error correction and supplies this to a control voltage generation circuit 13. Upon receiving the correction error amount signal, the control voltage generation circuit 13 produces a control voltage inversely proportional to the correction error amount signal and the variably control the oscillation frequency of a control voltage oscillator 12 by this control voltage. The control voltage oscillator 12 sets a clock frequency in proportion to the control voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus for adaptively controlling a disk rotation speed, that is, a reproduction speed based on correction processing information obtained in a reproduction process of an optical disk.

[0002]

2. Description of the Related Art An optical disk reproducing apparatus 1 shown in FIG.
An optical disk 2 such as an OM is driven to rotate by a disk motor 3, and a read signal of an optical pickup 4 that scans a signal recording surface of the optical disk 2 is processed by a signal processing circuit 5. The signal processing circuit 5 performs error correction processing on digital data included in the read signal supplied from the optical pickup 4, outputs a reproduced signal such as audio or video to the outside, and outputs a synchronization signal included in the read signal to a reference clock oscillator. A motor drive signal is supplied to the disk motor 3 so that the disk motor 3 synchronizes with the reference clock supplied from the reference clock 6, that is, the phase comparison error of the synchronization signal with respect to the reference clock converges to zero. Drive rotationally. Thus, the synchronization signal and the digital data are read out from the optical disk 2 in synchronization with the reference clock 3.

In recording on the optical disk 2, CLV (constant linear velocity) recording is often performed in order to increase the recording time. When such a CLV-recorded optical disk is reproduced by CLV, the disk rotation speed is about 1 / inner on the outer circumference with respect to the inner circumference. 2.5,
The performance of the disk motor cannot be fully utilized. Therefore, recently, a high-speed reproduction technique for reproducing an optical disk at a high speed of about 2 to 10 times the standard rotation speed and improving a data transfer rate by an increase in the reproduction speed has become popular. However, with the rapid spread of optical discs, optical discs of poor quality have begun to appear on the market. When such poor quality optical discs are reproduced at several times the standard rotational speed, digital data that can be read at standard rotational speeds However, accurate reading may not be possible due to an increase in the amount of correction errors exceeding the correction limit.

Therefore, in order to avoid such a reading defect, attention is paid to the fact that data can be read even at a rotational speed close to the rotational speed at the time of music reproduction, even with an optical disk of poor quality, and the data can be read by one access. If the signal cannot be output, a retry (retry) is performed, and at that time, the frequency of the reference clock is lowered, and the rotation speed is reduced to about 1/2 or 1/3 to read the data. Came to appear.

[0005]

When the data read from a bad optical disk is transferred to a personal computer or the like, the data transfer speed of the conventional optical disk reproducing device of the conventional reference clock variable type is adjusted to the disk rotation speed. Since the data transfer efficiency is reduced to about 1/2 or 1/3, the data transfer efficiency is low.
Since it takes about seconds, there is a problem that the overall processing speed is extremely reduced. In particular, when applied as a peripheral device of a personal computer whose processing speed is getting faster and faster, a retry optical disk reproducing apparatus may become a fatal defect that may detract from the high speed processing aimed at by the computer system. And so on.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to adaptively control a disk rotation speed, that is, a reproduction speed based on correction processing information obtained in a reproduction process of an optical disk.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a disk motor which rotates by applying a motor drive signal, and reads a synchronization signal and digital data from an optical disk which is rotated by the disk motor. The optical pickup and the digital data read by the optical pickup are subjected to error correction processing to be reproduced, and the phase of the synchronization signal read by the optical pickup is compared with a reference clock supplied from the outside. A signal processing circuit that outputs a motor drive signal,
Reproduction speed adaptive control means, supplied with a signal indicating a correction error amount from the signal processing circuit, and supplying a reference clock having a frequency substantially proportional to the correction error amount to the signal processing circuit. Things.

Further, according to the present invention, the reproduction speed adaptive control means generates a control voltage proportional to the error correction amount, and the control voltage generation circuit is substantially proportional to the control voltage supplied from the control voltage generation circuit. Oscillates at the oscillation frequency,
A voltage-controlled oscillator for supplying a reference clock having the oscillation frequency to the signal processing circuit.

Further, in the present invention, the reproduction speed adaptive control means includes a control voltage generation circuit for generating a control voltage proportional to the error correction amount, and a control voltage generation circuit inversely proportional to the control voltage supplied from the control voltage generation circuit. A voltage-controlled oscillator that oscillates at an oscillation frequency and supplies a reference clock of the oscillation frequency to the signal processing circuit.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating an embodiment of an optical disk reproducing apparatus according to the present invention, and FIG. 2 is a diagram illustrating a relationship between a correction error amount and a reference clock frequency.

The optical disk reproducing apparatus 11 shown in FIG. 1 adaptively controls the rotation speed of the optical disk 2 according to the correction error amount. The basic configuration of the optical disk reproducing apparatus 11 is almost the same as that of the conventional one except for a voltage control oscillator 12 and a control voltage generating circuit 13. That is, the optical pickup 4 for reading the synchronization signal and the digital data from the optical disk 2 and the signal processing circuit 5 for processing the read signal of the optical pickup 4 and for generating the disk motor drive signal use substantially the same circuit blocks as in the prior art. Can be However, the signal processing circuit 5 includes the optical disk 2
In the process of reproducing the read signal, the error correction processing is performed by decoding the Reed-Solomon code. At this time, the number of pointers indicating the error position observed for each predetermined number of frames is accumulated and corrected. It is configured to output as an error amount signal. It should be noted that the accumulation of the number of pointers may be performed not only in units of a certain number of frames but also in units of a certain time, for example.

A voltage controlled oscillator 12 which replaces the reference clock oscillator 6 supplies a clock having an oscillation frequency proportional to a control voltage supplied from the outside to the signal processing circuit 5 as a reference clock. The control voltage generating circuit 13 connected between the processing circuits 5 is supplied with a correction error amount signal from the signal processing circuit 5, generates a control voltage inversely proportional to the correction error amount, and supplies the control voltage to the voltage controlled oscillator 12. The voltage controlled oscillator 12 has a variable resistor Rv so that the free-running (self-running) frequency can be adjusted.
Is externally connected, and the standard reproduction speed can be variably set by changing the resistance value of the variable resistor Rv.

When the disk motor 3 is driven to rotate and the signal recording surface of the optical disk 2 is scanned by the optical pickup 4, a read signal including digital data and a synchronization signal is supplied from the optical pickup to the signal processing circuit 5. The signal processing circuit 5 performs an error correction process on the digital data and externally outputs the digital data as a video or audio reproduction signal. The phase of the synchronization signal is compared with a reference clock supplied from the voltage controlled oscillator 12, and a motor drive signal corresponding to the phase comparison error is applied to the disk motor 3.
The rotation of the disk motor 3 is controlled so that the phase comparison error converges to zero. However, in the course of the error correction processing, the signal processing circuit 5 generates a correction error amount signal proportional to the correction error amount, and supplies this to the voltage control generation circuit 13.

The voltage control generator 13 supplied with the correction error signal generates a control voltage inversely proportional to the correction error signal as shown by the dotted line in FIG. The oscillation frequency is variably controlled. Therefore, when the optical disc 2 being reproduced is a high quality disc without deterioration, the correction error amount signal is small,
The control voltage generated by the control voltage generation circuit 13 is considerably large. For this reason, the voltage controlled oscillator 12 supplied with the control voltage generated by the control voltage generating circuit 13 sets the clock frequency to the maximum or a high frequency close to it in proportion to the control voltage as shown by the solid line in FIG. I do. As a result, the target rotation speed of the disk motor 3 is set to be high, and high-speed reproduction is performed.

On the other hand, when the optical disk 2 being reproduced is a deteriorated low quality disk, the correction error amount signal is large and the control voltage generated by the control voltage generating circuit 13 is small. For this reason, the voltage controlled oscillator 12 supplied with the control voltage generated by the control voltage generating circuit 13 sets the clock frequency to the standard frequency or a low frequency close to the standard frequency as shown by the solid line in FIG. As a result, the disk motor 3
Is set to a lower value, and reproduction is performed at a standard speed or a speed close thereto. That is, the rotation speed of the disk motor 3 is reduced until no correction error occurs, and the optical disk 2 is driven at the maximum rotation speed allowed within a range where no correction error occurs. Even at 2, the maximum high-speed reproduction is realized within the allowable limit.

As described above, the optical disk reproducing device 11
Is based on a configuration in which the quality of the optical disk 2 is determined based on the correction error amount during execution of error correction, the oscillation frequency of the reference clock is controlled in accordance with the correction error amount, and the rotation speed is reduced when the correction error amount is large. In the case of the optical disc 2 having deteriorated quality that cannot withstand double-speed reproduction several times the standard reproduction speed,
Since the rotation speed can be adaptively controlled based on the correction error amount, and the optical disk 2 is reproduced at the maximum speed within a range where no correction error occurs, the rotation speed satisfying the maximum reproducible data transfer rate is always constant. Since the time can be maintained and the retry is not performed after switching the reference clock as in the conventional device, the reproduction efficiency can be maximized and the high speed processing of a personal computer or the like can be contributed.

The reproducing speed adaptive control means includes a control voltage generating circuit 13 for generating a control voltage inversely proportional to the correction error amount, and an oscillating frequency substantially proportional to the control voltage supplied from the control voltage generating circuit 13. A voltage controlled oscillator 12 which oscillates and outputs a reference clock having this oscillation frequency
When the correction error amount is small, the control voltage becomes large, and the oscillation frequency of the voltage controlled oscillator 12 becomes high. Therefore, the target reproduction speed is set to be high, and high-speed reproduction is performed. Conversely, when the correction error amount is large, the control voltage becomes small, and the oscillation frequency of the voltage controlled oscillator 12 becomes low. Therefore, the target reproduction speed is set to be low, and reproduction close to standard reproduction is performed. Reproduction at an optimum speed according to the quality of the optical disc 2 can be performed.

In the above-described embodiment, the control voltage generating circuit 13 for generating a control voltage proportional to the correction error amount,
Although the oscillator oscillates with an oscillation frequency substantially proportional to the control voltage supplied from the control voltage generation circuit 13 and the voltage control oscillator 12 that supplies a reference clock of this oscillation frequency to the signal processing circuit 5, the reproduction speed adaptive control means is constituted. A reproduction voltage adaptive control means oscillates with a control voltage generation circuit for generating a control voltage proportional to the correction error amount, and an oscillation frequency inversely proportional to the control voltage supplied from the control voltage generation circuit; And a voltage-controlled oscillator that supplies the signal to the signal processing circuit 5.

[0019]

As described above, according to the optical disk reproducing apparatus of the present invention, the optical disk is rotated by the disk motor which is rotated by applying the motor drive signal, and the synchronization signal and the digital data are read by the optical pickup. The digital signal is supplied to a signal processing circuit, subjected to error correction processing and reproduced, and the phase of the synchronization signal is compared with a reference clock supplied from the outside, and a motor drive signal corresponding to the phase comparison error is output, thereby performing signal processing. Adaptive control means supplied with a signal indicating the correction error amount from the circuit,
Since the reference clock having a frequency substantially proportional to the correction error amount is supplied to the signal processing circuit, the quality of the optical disc is determined based on the correction error amount at the time of executing the error correction, and the reference clock is determined according to the correction error amount. The oscillation frequency is controlled, and the rotation speed can be reduced when the amount of correction error is large, so that even for an optical disc whose quality cannot withstand double-speed playback several times the standard playback speed, the rotation speed can be determined based on the amount of correction error. The optical disc can be reproduced at the maximum speed within the range where no correction error occurs, so that the rotation speed that satisfies the maximum data transfer rate that can be reproduced can always be maintained, and the standard Since there is no wasted time such as retrying after switching the clock, the playback efficiency is maximized and the personal computer An excellent effect such as can contribute to high-speed processing such as over data.

The reproducing speed adaptive control means generates a control voltage that is inversely proportional (proportional) to the correction error amount, and is proportional to the control voltage supplied from the control voltage generating circuit (inversely proportional). Oscillates at the oscillating frequency
A voltage-controlled oscillator that outputs a reference clock of the oscillation frequency; therefore, when the correction error amount is small, the control voltage becomes large (small), and the oscillation frequency of the voltage-controlled oscillator becomes high. When set to a high value, high-speed reproduction is performed, and conversely, when the correction error amount is large, the control voltage becomes small (large), and the oscillation frequency of the voltage-controlled oscillator becomes low. The reproduction is set to a low value, and reproduction close to the standard reproduction is performed, thereby producing effects such as reproduction at an optimum speed according to the quality of the optical disk.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an optical disk reproducing device of the present invention.

FIG. 2 is a diagram illustrating a relationship between a correction error amount and a reference clock frequency.

FIG. 3 is a schematic configuration diagram showing an example of a conventional optical disc reproducing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Optical disk reproducing apparatus 2 Optical disk 3 Disk motor 4 Optical pickup 5 Signal processing circuit 12 Voltage controlled oscillator 13 Control voltage generation circuit

Claims (3)

[Claims] 1. A disk motor that rotates by applying a motor drive signal, an optical pickup that reads a synchronization signal and digital data from an optical disk that is rotationally driven by the disk motor, and an error correction unit that corrects the digital data read by the optical pickup. A signal processing circuit that performs processing and reproduces, compares the phase of the synchronization signal read by the optical pickup with a reference clock supplied from outside, and outputs a motor drive signal according to the phase comparison error,
Reproduction speed adaptive control means, supplied with a signal indicating a correction error amount from the signal processing circuit, and supplying a reference clock having a frequency substantially proportional to the correction error amount to the signal processing circuit. Optical disc playback device. 2. The reproduction speed adaptive control means includes a control voltage generation circuit for generating a control voltage inversely proportional to the error correction amount, and an oscillation frequency proportional to the control voltage supplied from the control voltage generation circuit. 2. The optical disk reproducing apparatus according to claim 1, further comprising a voltage controlled oscillator for supplying a reference clock having the oscillation frequency to the signal processing circuit. 3. The reproduction speed adaptive control means includes a control voltage generation circuit for generating a control voltage proportional to the error correction amount, and an oscillation frequency that is inversely proportional to the control voltage supplied from the control voltage generation circuit. 2. The optical disk reproducing apparatus according to claim 1, further comprising: a voltage-controlled oscillator that supplies a reference clock having the oscillation frequency to the signal processing circuit.