KR0144840B1 - Data fault compensation method - Google Patents

Abstract

The present invention relates to a method for compensating for data in a device using a disk in advance by detecting a defect present in the data picked up from the disk before the defective data is output. Each sector data is divided into sectors, and the defect level of each sector is determined as a normal state, an error correctable state, a retryable state, or a nonrecoverable state. To compensate for the output. This improves the reliability of the data picked up and finally output from the disc even when a defect occurs due to scratches or dirt on the disc.

Description

Data defect compensation method

1 is a schematic system block diagram of a disk-use product having a conventional data storage memory.

2 is a detailed configuration diagram of the defect signal generating circuit of FIG.

3 is an input / output waveform diagram of each part of FIG.

4 is a block diagram for implementing a data defect compensation method according to the present invention.

5 is a defect data table stored in the table storage of FIG.

6 is a timing diagram for digitalizing a defect signal in FIG.

FIG. 7 is a partial operation flowchart of the microcomputer of FIG.

* Explanation of symbols for main parts of the drawings

11: pickup section 13: fault signal generating circuit

14: DSP 17: Fault compensation circuit

18: Mycom 19: Defective data storage

The present invention relates to a method for compensating for a disc defect in a product using a disc, and more particularly to a data defect compensation method for improving reliability of output data by detecting a disc defect early and compensating for the defect in advance. .

A typical system block diagram with data storage memory of a product using a disk is shown in FIG. The data is read from the disk by the pickup unit 11 and supplied to the RF amplifier 12. The RF amplifier 12 amplifies the input RF signal to an appropriate size and supplies it to the DSP (Digital Signal Processor) 14 do. The data on which data processing such as error correction is performed in the DSP 14 is stored in the memory 15. The DSP 14 reads out the data stored in the memory 15 and outputs it via the D / A conversion unit 19. In addition, the RF amplifier 12 includes a defect signal generation circuit 13. The defect signal generation circuit 13 detects a defect caused by dust or the like on the disk or a defect caused by an error in the system to detect a defect signal (DFT). Occurs. The defect signal DFT is supplied to the defect compensation circuit 17 of the servo controller 16. The defect compensating circuit 17 then compensates for the defect detected in accordance with the defect signal, and controls the servo of the pickup section 11 according to the compensation result. The microcomputer 18 supplies a control signal necessary for each operation unit described above.

FIG. 2 is a detailed circuit diagram showing the defect signal generating circuit 17 of FIG. 1, and FIG. 3 shows a waveform diagram of each operation part of the circuit of FIG. First, when an RF signal such as a third (a) diagram is input from the pickup unit 11, the defect amplifier 21 amplifies and outputs an input RF signal to a defective portion as shown in the third (b) diagram. The output signal of the defect amplifier 21 is supplied to the defect detector 22, and the defect detector 22 detects only the defective portion from the input signal as shown in FIG. Then, the comparator 23 compares the output signal of the defect detection unit 22 with a predetermined reference signal and outputs a defect signal DFT as shown in FIG.

When such a defect signal DFT is inputted to the defect compensation circuit 17, the defect compensation circuit 17 compensates for the defect by reducing the gain of data corresponding to the defect signal DFT.

However, when the defect compensation circuit 17 of the servo controller 16 compensates for the defect of the picked-up data by adjusting the focusing gain of the data according to the defect signal, it compensates for the data after the defect is detected. Only this is done and there is a problem in that the current data with a defect is output as it is.

Accordingly, the data defect compensation method according to the present invention aims to improve the reliability of output data by detecting and compensating for defects generated in data due to scratches or dust of a disc before outputting them.

An object of the present invention as described above is a method for compensating for defects in data read from a disk, comprising the steps of: sampling a defect signal of each sector data as digital defect data in the read data; Determining a state, DSP-processing and outputting the corresponding sector data according to the result of the discriminating step, muting and outputting the corresponding sector data according to the result of the discriminating step; Therefore, it is achieved by repeatedly retrying the determination of a defect degree state for a corresponding sector a predetermined number of times, and if the predetermined number of times is exceeded in the retrying step, muting the corresponding sector data and outputting the result. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram showing a part of a system for implementing a data defect compensation method according to the present invention. The defect signal DFT output from the defect signal generation circuit 13 is supplied to the defect compensation circuit 17 and also to the microcomputer 18. Then, the microcomputer 18 digitalizes the degree of the defect in accordance with the inputted defect signal DFT and stores it in the defect data storage unit 19.

A table of defect data stored in the defect data storage unit 19 is shown in FIG. In this table, if the fault data is 0000 ~ 000F, it is normal status, if it is 0010 ~ 0FFF, error correction is possible, if it is 1000 ~ 2FFF, it is retryable, and if it is 3000 ~ FFFF, it is not recoverable. Corresponding.

6 shows a timing diagram for digitally converting the defect signal DFT supplied from the defect signal generation circuit 13 into defect data at the microcomputer 18. As shown in FIG. First, data to be picked up is divided into sectors of a predetermined size, and sector synchronization with a period of 13.3 msec is given to each sector. The defect signal DFT of each sector is sampled at a sampling period of 1 MHz to obtain defect data for each sector. The defect data thus obtained is stored in a memory (not shown) provided in the microcomputer 18. Then, the state of the defect data stored in the memory is checked based on the table as shown in FIG. In this case, as shown in FIG. 6, the defect data may predict the defect state one sector before the sector data outputted by the DSP.

FIG. 7 is a flowchart illustrating a process of inspecting a state of defect data in the microcomputer 18, and illustrates a process of repeatedly inspecting four times. First, defect data is read from the memory of the microcomputer (step 111). It is checked whether the read defect data is in a steady state (step 112). If the inspection result is normal, the corresponding sector data is DSPed (step 113) and output. On the other hand, if the defect data is not in the normal state as a result of the inspection, it is checked whether error correction is possible (step 114). If the result of the check is an error correctable state, the corresponding sector data is DSPed (step 115). The state of the corrected error is checked (step 116), and if error correction is made, the DPS data is outputted. On the other hand, if the test result is not in the error correctable state, it is checked whether the defect data is in the retryable state (step 117). Here, retrying means rechecking the state of defect data from the beginning. As a result of the inspection, if the defect data is in the retryable state, it is checked whether the number of retries is four or less (step 118). Here, the number of retries may be set to another number other than four, and the retries are repeatedly made as many as the set number of times. If the number of retries is four or less, the output of the sector data is prohibited and the address at which the current sector data is stored is stored (step 119). Then, the address immediately before the address of the current sector is searched (step 120). This is because an error may occur when searching the current sector address. Then, the address of the above-described current sector is searched (step 121). If the address of the current sector is found, the defect data of the sector is read again (step 111). Previously, if the number of retries exceeds four, the current sector data is muted (step 122) and output. Further, if the defect data is not in the retryable state (step 117), the sector data is determined to be in an unrecoverable state (step 123), muted and then output.

As described above, the data defect compensation method according to the present invention divides the data picked up from the disc into sectors of a predetermined size, detects defects for each sector, digitalizes the defect signal, and then defects of each sector. By classifying the defect level of data and processing the sector data according to the defect state, the defect of data is compensated for. In particular, since the defect state of the sector data can be predicted before one sector, the reliability of the final output data is further improved.

Claims (5)

CLAIMS What is claimed is: 1. A method for compensating for defects in data read from a disc, comprising: sampling a defect signal of each sector data into digital defect data in the read data; Determining a defect degree state of the defect data; DSP processing the sector data and outputting the sector data according to the determination result; Muting the corresponding sector data and outputting the corresponding sector data according to a result of the determining step; Retrying determination of a defect degree state for a corresponding sector by a predetermined number of times according to a result of the determination step; And if the predetermined number of times is exceeded in the retrying step, muting the corresponding sector data and outputting the muted data. The method of claim 1, wherein the determining of the defect degree state comprises: a first inspection step of checking whether the defect data is in a normal state; A second inspection step of checking whether the defect data is in an error correctable state when it is not in a normal state in the first inspection step; A third inspection step of checking whether the defect data is in a retryable state when it is not an error correctable state in the second inspection step; And determining the defect data as an unrecoverable state when it is not in a retryable state in the third inspection step. The method of claim 2, wherein the determining of the defect degree state comprises dividing the minimum value to the maximum value of the defect data into a plurality of sections having a predetermined range. A data defect compensation method, characterized by determining the degree of defect status. The method of claim 1 or 2, wherein the retrying step comprises: checking whether a current number of retries is within a predetermined number when the defect data is in a retryable state; Prohibiting output of the current sector data if the test result is within a predetermined number of times, and storing an address of the sector; Searching the stored sector address in a memory in which data is stored; And rereading the defect data corresponding to the sector of the searched address. 5. The data defect compensation method according to claim 4, wherein said searching step is a step of performing a search from a previous address by a predetermined address from said stored sector address.