KR19980040666A - Scratch Compensation System for Optical Disc Data Reproduction System - Google Patents

Abstract

Disclosed is a scratch compensation device for use in an optical disc data reproducing system. A photodetector for converting and outputting an optical signal including data into an electrical signal, a track error detector for detecting an amount of tracking error by inputting an electrical signal, and a tracking motor corresponding to the tracking error amount and gain control signals. The apparatus used in the optical disc data reproducing system including the controlling tracking servo and the control unit includes: a low pass filter for low pass filtering the input tracking error amount and outputting the low filtered filtering error amount to the tracking servo; Removes the crease, responds to the lock signal indicating the stable state of the tracking servo and the anti-shock signal caused by external shock, generates a filter control signal corresponding to the section where the scratch is generated, and responds to the command generated from the controller The output of the scratch control means and the track error detector to output the gain control signal. Characterized in that in response to a motor control signal comprising a signal selecting means for selectively outputting the output to a low pass filter or a tracking servo, and the faster tracking servo has the effect to follow a track.

Description

Scratch Compensation System for Optical Disc Data Reproduction System

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical disk data reproducing systems such as compact disk players (CDP) and the like, and more particularly to scratch compensation circuits used in circuits such as CDP and the like.

For example, the conventional compact disc player pre-signal processing unit has a built-in function for reinforcing the function of the tracking servo and the cracking of radio frequency signals caused by a defect on the disc when the compact disc is being played. .

1 (a) to 1 (d) are timing diagrams for explaining a conventional defect correction, where (a) is a radio frequency signal, (b) is a defect signal, and FIG. 1 (c) shows a normal tracking error, and FIG. 1 (d) shows waveform diagrams of a low pass filtered tracking error signal, respectively.

In the conventional defect correction function, the defect signal shown in FIG. 1B is extracted from the radio frequency signal shown in FIG. 1A, and in response to the extracted defect signal, FIG. The low pass filtering of the tracking error signal as shown in FIG. Therefore, the level of the tracking error signal due to defect is attenuated, so that the tracking servo can perform the tracking faster.

2 (a) to 2 (c) are waveform diagrams for explaining the scratch, in which (a) is a radio frequency signal, (b) is a mirror signal and (b) of FIG. c) shows a waveform diagram of the tracking error signal, respectively.

The conventional method includes the function of correcting the defect signal shown in Fig. 1, but the function for correcting the deviation of the track due to scratches such as continuous scratches is not inherent.

That is, if scratches occur for some reason, the radio frequency signal shown in Fig. 2A appears as the mirror signal shown in Fig. 2B. Therefore, there has been a problem in that the level of the error signal due to the scratches increases and the radio frequency signal collapses out of the track tracked by the tracking servo.

An object of the present invention is to provide a scratch compensation device of an optical disk data reproducing system capable of compensating not only a defect effect but also a scratch effect.

1A to 1D are timing diagrams for explaining a conventional defect correction.

2 (a) to 2 (c) are waveform diagrams for explaining the scratch.

3 is a block diagram illustrating a scratch compensation device according to the present invention.

4 is a block diagram of a preferred embodiment of the present invention of the scratch control unit shown in FIG.

In order to achieve the above object, an optical detector for converting and outputting an optical signal containing data into an electrical signal, a track error detection unit for inputting the electrical signal to detect a tracking error amount, the tracking error amount and gain control The scratch compensation device used in the optical disk data reproducing system according to the present invention, which includes a tracking servo and a control unit for controlling a tracking motor in response to signals, performs low pass filtering on an input tracking error amount, and a low pass filtering. The scratches are generated in response to a low pass filter for outputting the tracking error amount to the tracking servo, a scratch, and a lock signal indicating a stable state of the tracking servo and an anti-shock signal caused by external shock. A filter control signal corresponding to the received section, and is generated from the controller And a scratch control means for outputting the gain control signal in response to the filter control signal, and a signal selecting means for selectively outputting the output of the track error detector to the low pass filter or the tracking servo in response to the filter control signal. It is desirable to be.

Hereinafter, the configuration and operation of the scratch compensation device according to the present invention will be described as follows with reference to the accompanying drawings.

3 is a block diagram illustrating a scratch compensation device according to the present invention, including a track error detection unit 10, a tracking servo 30, and a switch 20 constituting the compensation device 40 according to the present invention; A low pass filter (LPF) and scratch control unit 24 are included.

The track error detector 10 shown in FIG. 3 detects a tracking error amount by inputting an electrical data signal output from an optical detector (not shown) and including data, and switches the detected tracking error amount to the switch 20. Will output Here, the light detector (not shown) serves to irradiate light to the disk, reflect the light from the disk, convert an optical signal containing data into an electrical signal, and output the converted electrical signal.

The switch 20 performs a function of outputting the tracking error amount output from the track error detector 10 to the low pass filter 40 or the tracking servo 30 in response to the filter control signal C1. The tracking servo 30 inputs the tracking error amount output from the low pass filter 40 or the tracking error amount output from the track error detection unit 10 to output a control signal for controlling the tracking motor. In addition, the tracking servo 30 adjusts the gain of the servo in response to the gain control signal C2 output from the scratch control unit 24.

The low pass filter 40 inputs the tracking error amount selected by the switch 20 to filter the low pass component, and outputs to the tracking servo 30 the tracking error amount that the filtered level is offset.

If a scratch is generated, the tracking error amount output from the track error detector 10 is output to the LPF 40 in response to the signal generated by the scratch controller 24. The LPF 40 inputs a tracking error amount having a large level to filter the low frequency component, and outputs to the tracking servo 30 the tracking error amount with the low frequency component filtered to reduce the level.

However, when no scratch is generated, the tracking error amount output from the track error detection unit 10 is immediately output to the tracking servo 30 without low pass filtering.

On the other hand, the scratch control unit 24 inputs a command output from the mirror signal, the anti shock signal, the lock signal and the microcomputer (not shown) through the input terminals IN1, IN2, IN3 and IN4, Using the signals and outputting the filter control signal C1 and the gain control signal C2 generated in response to the system clock CK to the switch 20 and the tracking servo 30, respectively, eliminating scratches and scratches. The filter control signal is output according to the section in which the odor is generated.

Here, as described above, the mirror signal is a signal generated when a scratch occurs, the anti-shock signal is a signal generated by an external shock, and the lock signal is when the tracking servo is in a stable state. This signal is generated.

FIG. 4 is a block diagram of a preferred embodiment of the scratch control unit 24 shown in FIG. 3 according to the present invention, and includes a decoder 52, an inverted logical sum 54, and an AND ( 56) and the glitch removal and delay unit 60.

The decoder 52 shown in FIG. 4 inputs and decodes a command from the microcomputer through the input terminal IN4, and outputs the decoded value as an inverted logical sum 54. The inverted logical sum 54 inverts the OR of the anti-shock and lock signals input through the input terminals IN2 and IN3 and the output of the decoder 52, and outputs the result as the logical product 56.

The AND product 56 performs an AND operation on the output of the inverted AND 54 and the mirror signal input through the input terminal IN1, and outputs the result of the AND operation to the glitch removal and delay unit 60 as an interruption signal.

At this time, the glitch removal and delay unit 60 removes the glitch when the interruption signal is input from the logical product 50, and provides a filter control signal for delaying the tracking error amount by the period where the mirror signal is generated. Output In addition, the glitch removal and delay unit 60 outputs a gain control signal C2 for controlling the servo gain of the tracking servo 30 in response to a command signal input through the input terminal IN4.

In the glitch removal and delay unit 60, a difference in the width of the glitch and the amount of track errors may occur due to the characteristics of the glitch. At this time, a command indicating a glitch removal section for controlling the width from the microcomputer, i.e., where and how far to remove glitch, is input. For example, this command consists of 2 bits, indicating the delay time as shown in Table 1 below.

Delay control bit pattern Delay Clock Count Delay time 0 1 clock 11㎲ One 2 clock 22㎲ 10 3 clock 33㎲ 11 4 clock 44㎲

By using the lower two bits of the address allocated from the microcomputer as the delay control bits shown in Table 1, the four bits of each of the two bits can be designed to have a delay of 11 to 44 ms.

For example, when controlling the low pass filter 40, the gain of the tracking error amount must be doubled by a command from a microcomputer (not shown) due to an anti-shock signal due to an external shock, a lock release, or the like. Occurs. In this case, the glitch removal and delay unit 60 shown in FIG. 4 generates a filter control signal so as not to filter the low frequency component of the tracking error amount, and then removes the glitch and generates a gain control signal corresponding to the command. Control the gain of the servo.

As described above, the scratch compensation device of the optical disk data reproducing system according to the present invention has the effect of allowing the tracking servo to follow the track faster by compensating for the noise caused by the scratch as well as the defect. .

Claims (3)

An optical detector for converting and outputting an optical signal including data into an electrical signal, a track error detector for detecting an amount of tracking error by inputting the electrical signal, and tracking in accordance with the tracking error amount and gain control signals In the scratch compensation device used in an optical disk data reproducing system comprising a tracking servo and a control unit for controlling a motor, A low pass filter for low pass filtering the input tracking error amount and outputting the low pass filtered tracking error amount to the tracking servo; Removes the scratch, responds to the lock signal indicating the stable state of the tracking servo and the anti-shock signal due to external shock, generates a filter control signal corresponding to the section where the scratch is generated, and generates from the controller Scratch control means for outputting the gain control signal in response to a command; And And a signal selection means for selectively outputting the output of the track error detector to the low pass filter or the tracking servo in response to the filter control signal. . The method of claim 1, wherein the scratch control means Mirror control means for generating an interruption signal in response to the command, the mirror signal generated when the scratch occurs, the lock signal, and the anti-shock signal; And And a glitch removal and delay means for removing the scratch in response to the interruption signal and for generating the filter control signal corresponding to the section where the scratch occurred. Scratch compensation device. The method of claim 2, wherein the mirror control means A decoder for decoding the command; An inverted logical sum that inverts and outputs the output of the decoder, the inverted lock signal and the anti-shock signal; And And a logical product for logically multiplying the output of the mirror signal and the inverted logical sum by the logical signal and outputting the logical signal as the interruption signal.