KR100510497B1 - Apparatus for reading data from disc and method thereof - Google Patents

Abstract

The present invention is a disc reproducing apparatus and method which can reduce the read fail decision rate for a disc by adjusting the waveform equalization parameter of the reproduction signal in the disc reproducing mode to improve readability to the disc.

Disc playback apparatus according to the present invention, the pickup unit for detecting the amount of light reflected from the disk; A high frequency amplifying unit converting the amount of light output from the pickup unit into an electrical high frequency signal, waveform equalizing the high frequency signal, and detecting jitter of the waveform equalized high frequency signal; If the data read from the disc is recognized as an error, the waveform equalization variable is set to change the jitter detected by the high frequency amplification unit, and the pickup unit controls to retry reading of the data recording surface of the disc recognized as the error. If the detected jitter is greater than the reference jitter or the detected jitter is not greater than the reference jitter after the adjustment of the waveform equalization variable for a plurality of times, but the data read from the disc is recognized as an error, the process of retrying the read while reducing the rotation speed of the disc It includes a system control unit for determining the read failure to the disk.

Therefore, it is possible to reduce the disc read failure decision rate due to scratches or defects or defects present in the disc.

Description

Apparatus for reading data from disc and method

The present invention relates to a disc reproducing apparatus and method, and more particularly, to a disc reproducing apparatus and method capable of reducing the incidence of read fail for data recorded on a disc.

Disc currently proposed disc playback apparatuses include CD (Compact Disc) only devices, DVD (Digital Versatile Disc, hereinafter referred to as DVD) only devices, and devices capable of accommodating both CD and DVD.

If a read NG (No Good) is generated in the reproducing mode and the data read from the disc is recognized as an error, the disc reproducing apparatus retries reading the data recording surface of the disc on which the read NG is generated. The retry may be performed several times repeatedly. If the read NG is generated even after the read retry, the existing disc reproducing apparatus lowers the rotation speed of the disc, and then attempts to read the data recording surface of the disc on which the read NG is generated. The read retry process according to the generation of the read NG described above is performed while lowering the rotation speed of the disc to the minimum speed set in the disc reproducing apparatus.

For example, in the case of a disc player with a maximum speed of 48X, a minimum speed of 8X and other configurable speeds of 40X, 32X, 24X, if a read NG occurs in the playback mode, the disc rotates from 48X to 40X. Slow down and retry reading. However, in the case of read NG even in 40X, the read speed is retried by lowering the disk rotation speed to 32X. If reading NG occurs in 32X, read speed is lowered by 24X and then retry reading.

If a read OK occurs while retrying reading by lowering the rotational speed of the disk as described above, the disk playback apparatus continues the normal playback mode. However, in spite of the retry of reading by lowering the rotational speed of the disc to the lowest double speed as described above, when the read NG is generated, the disc reproducing apparatus determines that the currently loaded disc is read fail. .

In the case where scratches or defects or scratches are present on the disc, the quality of the reproduction signal is degraded in the region where the scratches or defects or scratches are present, so that the rotational speed of the disc is reduced as mentioned above. Even if it is down, there is a good chance that the disk will be read fail. If it is determined that the disc has failed to read, the disc reproducing apparatus cannot normally perform the reproducing mode for the disc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disc reproducing apparatus and method capable of reducing the read fail decision rate for a disc by improving readability of the disc in a disc reproducing mode.

Another object of the present invention is to provide a disc reproducing apparatus and method that can reduce the read failure decision rate for a disc due to scratches, defects, or defects present in the disc by adjusting waveform equalization parameters for the reproduction signal.

In order to achieve the above objects, a disk reproducing apparatus according to the present invention comprises: a pickup section for detecting an amount of light reflected from the disk; A high frequency amplifying unit converting the amount of light output from the pickup unit into an electrical high frequency signal, waveform equalizing the high frequency signal, and detecting jitter of the waveform equalized high frequency signal; If the data read from the disk is recognized as an error, the waveform equalization variable is set to change the jitter detected by the high frequency amplification unit, and the pickup section resumes reading the data recording surface of the disk recognized as the error. It is preferable to include a system controller for controlling to attempt.

If the jitter detected by the high frequency amplifier is greater than the reference jitter, the system controller preferably sets the waveform equalization variable for changing the jitter. The waveform equalization parameter preferably includes a cutoff frequency and boost level of the high pass filter for the high frequency signal.

When the detected jitter is greater than the reference jitter, the system controller may set the waveform equalization variable so that any one of a cutoff frequency set in the high frequency amplifier and the boost level is changed.

Preferably, the system controller sets the waveform equalization variable to a value adjacent to a cutoff frequency and a boost level preset in the high frequency amplifier.

The disc reproducing apparatus further includes a motor for rotating the disc, and the system control unit retryes the read after the jitter change, so that the detected jitter is not larger than the reference jitter and the data read from the disc is an error. If it is not recognized as a normal playback mode for the disc and retrying the read, if the detected jitter is larger than the reference jitter or if the data read from the disc is recognized as an error, the rotation speed of the disc is increased. Preferably, the pickup unit and the motor are controlled such that a read retry is performed on the data recording surface of the disc recognized as the error while down.

In order to achieve the above objects, a disc reproducing method according to the present invention comprises the steps of comparing jitter detected in a reproduced signal with reference jitter if data read from the disc is recognized as an error in the reproducing mode; If the detected jitter is greater than the reference jitter, adjusting a waveform equalization parameter of the high frequency signal to be reproduced to change the detected jitter in the reproduced signal; And retrying to read the data recording surface of the disk in which the read data is recognized as an error.

The waveform equalization parameter preferably includes a cutoff frequency and a boost level of the high pass filter for the high frequency signal.

In the adjusting of the waveform equalization variable, one of the cutoff frequency and the boost level may be adjusted.

Adjusting the waveform equalization variable, adjusting the waveform equalization variable of one of the cutoff frequency and the boost level, and then comparing the detected jitter in the reproduction signal generated by the read retry with the reference jitter. ; If the detected jitter is greater than the reference jitter, restoring the adjusted waveform equalization variable to its original value and adjusting the other unequalized waveform equalization parameter; Adjusting the other waveform equalization variable and then comparing the detected jitter with the reference jitter in the reproduction signal generated by the read retry; If the detected jitter is greater than the reference jitter, it is desirable to include restoring the other waveform equalization variable to its original value.

In the disc reproducing method, if the detected jitter is not larger than the reference jitter, but the data read from the disc is recognized as an error or the detected jitter is larger than the reference jitter even after adjusting the waveform equalization variable, Preferably, the method further comprises performing a read retry on the data recording surface of the disk while lowering the rotation speed.

After retrying reading of the data recording surface, if the data read from the disk is not recognized as an error, it is preferable to further include performing a normal playback mode for the disk.

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

1 is a functional block diagram of a disc reproducing apparatus according to a preferred embodiment of the present invention. Referring to FIG. 1, a disc reproducing apparatus includes a disc 101, a pickup unit 102, a high frequency (RF) amplifying unit 103, an end deck (ENDEC) 104, a system control unit 105, and a servo control unit 106. , Drive circuit 107, and spindle motor 108.

The disc 101 is a disc capable of reproducing recorded information. The disk 101 may be a CD-based disk or a DVD-based disk.

The pickup section 102 detects and outputs the amount of light reflected from the data recording surface of the disk 101. For this purpose, the pickup section 102 includes a photo detector (not shown). In addition, the pickup section 102 is controlled by the drive circuit 107 to retry reading the same data recording surface of the disk 101.

The RF amplifier 103 converts the amount of reflected light detected by the pickup unit 102 into an electrical RF signal and transmits the converted RF signal to the end deck 104. At this time, the RF amplifier 103 waveform-equalizes the reproduction signal converted into the electrical RF signal by the waveform equalizer 103_1 shown in FIG. 1 and transmits the waveform to the end deck 104.

The waveform equalizer 103_1 increases the level of the RF signal reproduced by the set boost level and the cutoff frequency of the high pass filter, and removes the high frequency noise of the RF signal having the increased level. Waveform equalization of the RF signal.

In addition, the RF amplifier 103 detects jitter from the waveform equalized reproduction signal by the waveform equalizer 103_1 using the jitter detector 103_2 shown in FIG. The method of detecting jitter from the reproduction signal uses one of the known methods. For example, jitter can be detected by slicing the level of the reproduction signal. The jitter detected by the jitter detector 103_2 is transmitted to the system controller 105.

The end deck 104 combines the functions of an encoder and a decoder. The RF signal transmitted from the RF amplifier 103 is decoded to be transmitted to a host computer (not shown). In the decoding, various functions are performed on the end deck 104, in particular, an error correction process is performed on the reproduced RF signal. As a result of the error correction process, if the signal to be reproduced is determined to be an error, the read NG signal is transmitted to the system control unit 105. However, if it is determined that the reproduced signal is normal, the read OK signal is transmitted to the system control unit 105.

When the system control unit 105 receives a read OK signal from the end deck 104, the system control unit 105 determines that the data read from the current disc 101 is normal, and the normal playback mode can be performed on the disc 101. Control the operation.

However, when a read NG signal is received from the end deck 104, the system control section 105 recognizes the data currently read from the disk 101 as an error (abnormal). Accordingly, the system controller 103 compares the jitter transmitted from the RF amplifier 103 with a preset reference jitter. The reference jitter is the minimum jitter that can be carried in the reproduction signal and is an experimentally determined value.

If the jitter transmitted from the RF amplifier 103 is greater than the preset reference jitter, the system controller 105 adjusts the waveform equalization parameter for the waveform equalizer 103_1. That is, adjacent values that can be set based on the cut-off frequency and the boost level of the high pass filter for the reproduction signal (RF signal) preset in the waveform equalizer 103_1 are used. To adjust the waveform equalization parameters. For example, if the set boost level is 5.3 dB, the adjacent values may be 4.2 dB and 6.3 dB. If the cutoff frequency set is 16 kHz, the adjacent values may be 8 kHz and 32 kHz.

The system controller 105 may set a waveform equalization variable to one of the adjacent values. For example, the boost level may be adjusted twice using the adjacent values for the boost level, and the cutoff frequency may be adjusted twice using the adjacent values for the cutoff frequency.

Each time the waveform equalization variable is adjusted, the system control section 105 controls the read retry on the data recording surface of the disk 101 in which an error has occurred. In addition, when the detected jitter is larger than the reference jitter by comparing the detected jitter with the reference jitter, the controller controls to perform all four waveform equalization parameter adjustment processes. However, after the waveform equalization parameter adjustment, if the detected jitter is not greater than the reference jitter, all four waveform equalization parameter adjustment processes may not be performed. That is, if the detected jitter is not greater than the reference jitter, the system controller 105 does not perform the waveform equalization parameter adjustment to change the jitter.

The system control unit 104 determines that the detected jitter is greater than the reference jitter even after the four adjustments of the waveform equalization variable, or the detected jitter is not greater than the reference jitter, but the read NG signal from the end deck 104 is not received after the read retry. When the data to be transmitted and reproduced is recognized as an error, the operation of the disc reproducing apparatus is controlled such that a read retry process is performed on the data recording surface of the disc 101 where the error occurs while the rotational speed of the disc 101 is decreased. .

The process of performing the read retry while lowering the rotational speed of the disc 101 may be performed as mentioned in the related art. Although the read speed is reduced by the rotation speed of the disc 101, when the read NG signal is transmitted from the end deck 104, the system controller 105 determines the read failure of the disc 101. Do it.

The servo control unit 106, when a read retry is requested by the system control unit 105, allows the pickup unit 102 to detect the amount of light reflected from the data recording surface of the disk 101 previously accessed (the 107). In addition, the spindle motor 108 is controlled to be rotated at a desired speed when reading is attempted while the disk rotation speed is lowered, and the pickup unit 102 controls the amount of light reflected from the data recording surface of the disk 101 as described above. The drive circuit 107 is controlled to be detected.

The drive circuit 107 is controlled by the servo control unit 106 to control the operation of the spindle motor 108 and the pickup unit 102. Spindle motor 108 is controlled by drive circuit 107 to rotate disk 101.

2 is a flowchart illustrating a disc reproducing method according to an exemplary embodiment of the present invention.

In the reproducing mode for the disc 101, when a read NG signal is generated from the end deck 104, the system controller 105 recognizes the data read from the disc 101 as an error and flows as shown in FIG. It works according to.

That is, in step 201, the system controller 105 detects jitter of a signal (RF signal) currently being reproduced based on the jitter transmitted from the RF amplifier 103. In operation 202, the system controller 105 compares the detected jitter with a preset reference jitter. The reference jitter is the same as the reference jitter described with reference to FIG. 1.

If it is determined that the jitter detected in step 202 is greater than the reference jitter, the system controller 105 adjusts the cutoff frequency of the high pass filter (HPF) of the reproduction signal (RF signal) to a low level. At this time, the system controller 105 cuts off the adjacent low frequencies of the waveform equalizer 103_1 based on the cutoff frequency currently set in the waveform equalizer 103_1 of the RF amplifier 103 as described with reference to FIG. 1. Set to frequency. For example, when the cutoff frequency preset in the waveform equalizer 103_1 is 16 kHz, 8 kHz is set as the cutoff frequency.

In step 204, the system controller 105 detects jitter of a signal to be reproduced after retrying reading of the data recording surface of the disc 101 recognized as an error. The jitter detected in step 205 is compared with the reference jitter. If it is determined that the detected jitter is greater than the reference jitter, in step 206, the system controller 105 sets the cutoff frequency of the high pass filter of the reproduction signal to a high frequency adjacent to the cutoff frequency previously set in the waveform equalizer 103_1. Adjust For example, when the cutoff frequency preset in the waveform equalizer 103_1 is 16 kHz, 32 kHz is set as the cutoff frequency.

Then, in step 207, the system controller 105 detects jitter of the signal to be reproduced after retrying reading of the data recording surface of the disc 101 recognized as an error.

The jitter detected in operation 208 is compared with the reference jitter. If it is determined that the detected jitter is greater than the reference jitter, in step 209, the system controller 105 restores the cutoff frequency of the high pass filter and adjusts the boost level. That is, the boost level is set to a large level adjacent to the boost level preset in the waveform equalizer 103_1. For example, if the boost level preset in the waveform equalizer 103_1 is 5.3 dB, the boost level is set to 6.3 dB.

In operation 210, the system controller 105 detects jitter of a reproduced signal after retrying reading of the data recording surface of the disk 101 that is recognized as an error.

The jitter detected in step 211 is compared with the reference jitter. If it is determined that the detected jitter is greater than the reference jitter, in step 211, the system controller 105 adjusts the boost level to an adjacent small level based on the boost level previously set in the waveform equalizer 103_1. For example, if the boost level preset in the waveform equalizer 103_1 is 5.3 dB, the boost level is set to 4.3 dB.

The above-described adjacent values are experimentally obtained values and values previously held by the system controller 105.

In step 213, the system controller 105 detects jitter of a reproduced signal after retrying reading of the data recording surface of the disc 101 that is recognized as an error.

The jitter detected in step 214 is compared with the reference jitter. If it is determined that the detected jitter is greater than the reference jitter, the system controller 105 restores the boost level at operation 215. In step 216, the system controller 105 proceeds to a mode (a disk rotation speed down mode) in which a read retry process for the disk 101 is performed while the rotation speed of the disk 101 is decreased. The disk rotation speed down mode monitors whether the read NG is generated while lowering the rotation speed of the disk from the highest speed to the lowest speed that can be set in the disk reproducing apparatus, as described in the above-described prior art, and according to the monitoring result of the disk ( 101) to determine the read failure.

On the other hand, if it is determined that the jitter detected in steps 202, 205, 208, 211, and 214 is not greater than the reference jitter, the system controller 105 determines that the disk is recognized as an error in step 217. The reading of the data recording surface of 101 is attempted again. In operation 218, it is monitored whether a read NG is generated from the end deck 104. If it is monitored in step 218 that no read NG is generated from the end deck 104, the system controller 105 proceeds to the normal playback mode for the disc 101 in step 219. However, if it is determined in step 218 that the read NG is generated, the system controller 105 proceeds to step 216.

FIG. 2 shows a sequence of adjusting the cutoff frequency low and then high again to change the jitter of the reproduction signal, and adjusting the boost level again and then decreasing it again. However, the waveform equalization parameter is used to change the jitter of the reproduction signal. The order of adjustment can be changed.

According to the present invention described above, when read NG is generated on the disc, the waveform equalization variable is adjusted to change the jitter of the reproduced signal to monitor the generation of the read NG, and the reproduction process is performed by performing the monitoring process a plurality of times. If the jitter of the playback signal is larger than the reference jitter or the jitter of the playback signal is not greater than the reference jitter in spite of the jitter change, but the read NG is generated, the process of retrying the read by lowering the disk rotation speed is performed. As a result, by determining whether or not to read the disc, there is an effect that can reduce the possibility that the read failure to the disc due to the presence of scratches, defects and scratches in some areas of the disc.

The present invention is not limited to the above-described embodiments, and variations of the present invention can be made by those skilled in the art within the spirit of the present invention. Therefore, the scope of claims in the present invention will not be defined within the scope of the detailed description will be defined by the claims below.

1 is a functional block diagram of a disc reproducing apparatus according to a preferred embodiment of the present invention.

2 is a flowchart illustrating a disc reproducing method according to an exemplary embodiment of the present invention.

Claims (12)

delete delete In the disc playback apparatus, A pickup unit detecting an amount of light reflected from the disk; A high frequency amplifying unit converting the amount of light output from the pickup unit into an electrical high frequency signal, waveform equalizing the high frequency signal, and detecting jitter of the waveform equalized high frequency signal; If the data read from the disk is recognized as an error, the waveform equalization variable is set to change the jitter detected by the high frequency amplification unit, and the pickup section resumes reading the data recording surface of the disk recognized as the error. A system control for controlling to attempt, If the jitter detected by the high frequency amplification unit is larger than the reference jitter, the system controller sets the waveform equalization variable for changing the jitter, And wherein said waveform equalization parameter comprises a cutoff frequency and a boost level of a high pass filter for said high frequency signal. 4. The method of claim 3, wherein the system controller sets the waveform equalization variable so that any one of a cutoff frequency set in the high frequency amplifier and the boost level is changed when the detected jitter is larger than a reference jitter. Disc player. 4. The disc reproducing apparatus according to claim 3, wherein the system controller sets the waveform equalization variable to a value adjacent to a cutoff frequency and a boost level preset in the high frequency amplifier. In the disc playback apparatus, A pickup unit detecting an amount of light reflected from the disk; A high frequency amplifying unit converting the amount of light output from the pickup unit into an electrical high frequency signal, waveform equalizing the high frequency signal, and detecting jitter of the waveform equalized high frequency signal; If the data read from the disk is recognized as an error, the waveform equalization variable is set to change the jitter detected by the high frequency amplification unit, and the pickup section resumes reading the data recording surface of the disk recognized as the error. A system control unit controlling to attempt; A motor for rotating the disk, If the detected jitter is not greater than a reference jitter and data read from the disc is not recognized as an error as a result of retrying the read after the jitter change, the system controller performs a normal play mode for the disc, and As a result of retrying reading, if the detected jitter is larger than the reference jitter or if the data read from the disk is recognized as an error, retrying reading to the data recording surface of the disk recognized as the error while reducing the rotation speed of the disk And controlling the pick-up unit and the motor to be performed. delete In the disc playback method, If the data read from the disc is recognized as an error in the reproduction mode, comparing the jitter detected in the reproduced signal with the reference jitter; If the detected jitter is greater than the reference jitter, adjusting a waveform equalization parameter of the high frequency signal to be reproduced to change the detected jitter in the reproduced signal; Retrying to read the data recording surface of the disc in which the read data is recognized as an error; Wherein said waveform equalization parameter comprises a cutoff frequency and a boost level of a high pass filter for said high frequency signal. 9. The method of claim 8, wherein adjusting the waveform equalization variable adjusts one of the cutoff frequency and the boost level to be changed. 9. The method of claim 8, wherein adjusting the waveform equalization variable comprises: Adjusting a waveform equalization parameter of one of the cutoff frequency and the boost level, and then comparing the detected jitter in the reproduction signal generated by the read retry with the reference jitter; If the detected jitter is greater than the reference jitter, restoring the adjusted waveform equalization variable to its original value and adjusting the other unequalized waveform equalization parameter; Adjusting the other waveform equalization variable and then comparing the detected jitter with the reference jitter in the reproduction signal generated by the read retry; If the detected jitter is greater than the reference jitter, restoring the other waveform equalization parameter to its original value. 11. The disk reproducing method according to claim 8 or 10, wherein the detected jitter is not greater than the reference jitter, but the detected jitter even after the data read from the disc is recognized as an error or the waveform equalization parameter is adjusted. Is greater than the reference jitter, further comprising retrying reading of the data recording surface of the disk while lowering the rotational speed of the disk. 10. The disc reproducing method of claim 8, further comprising: performing a normal play mode for the disc if data read from the disc is not recognized as an error after retrying reading of the data recording surface.