KR100218091B1 - Method and apparatus for reproducing a disc in audio system - Google Patents

Abstract

The disc reproducing apparatus and its method detects a defect (scratch) in the TOC (Table Of Contents) recording area when reproducing the disc, and checks the no-signal portion of the data recording area while moving the optical pickup to the outermost circumference of the disc when a scratch is detected. By displaying the number of songs for the unsigned part checked at the same time and moving the optical pickup to the beginning of the data recording area to play the disc, even if a scratch occurs on the disc, audio data continues to be the same as normal playback of the disc. It can have the effect of improving the performance and the reliability of the product of the disc playback apparatus by enabling the playback.

Description

Disc player and its method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing system. In particular, a disc capable of detecting a scratch in a table of contents (TOC) of a disc, reproducing the recording data of the TOC area using the data recording area, and reproducing the data recording area. A playback apparatus and method thereof are provided.

Generally, a disc, or compact disc (CD), is divided into three signal areas as shown in FIG. That is, it consists of a read in area from a disk inside, a read area, a program area, and a read out area.

Here, in the lead-in area, the address (position on the disc), the time and total time of each song recorded on the disc are recorded, and this area is called a TOC (Table Of Contents) area. That is, the table of contents is recorded by combining the contents of the records. The lead-in area continues within 46 mm in diameter and continues until immediately before the program start position of 50 mm in diameter, but the TOC signal is repeatedly recorded in this area.

Recently, most CD-players display the number of songs in the disc and the total playing time immediately when the disc is loaded, but this is because the TOC is read and displayed at the same time as the disc is loaded. This TOC information is also used for selection.

The data recording area (or program area) is an area in which music signals are recorded and starts at 50 mm in diameter and is recorded up to 116 mm in diameter.

The data end area (lead out area) is a signal area indicating the end of the program. A lead out signal (repetition pulse of 2 Hz) is recorded from the end position of the program area to an area 0.5 mm outside the radius (maximum area 117 mm phi). have.

With reference to the accompanying drawings, a signal processing system of a general disc for performing a reproducing operation of a disc (CD) divided into such regions will be described.

FIG. 1 is a block diagram showing a signal processing system of a general CD. The signal processing system of a CD is classified into a recorder and a playback system. Referring to FIG. 1, the structure of the recorder will be described first with reference to the encoder 18 and the recorder 19. ), The optical pickup 11 and the disc 10. Here, the optical pickup 11 is composed of a semiconductor laser diode that projects laser light to record input data on the disk 10 and a photodiode that receives light reflected from the disk 10 during reproduction.

The encoder 18 receives a bit string of input data consisting of 1s and 0s of binary information, converts it into a recording code string according to a modulation method, and provides the converted code string to the recording amplifier 19.

The provided code string is converted into a square wave current by the recording amplifier 19 and applied to the semiconductor laser of the optical pickup 11 to be recorded in each recording area of the above-described disk 10.

Some recorders have a recording correction function in order to improve the characteristics of the recording density and eventually reduce the waveform interference during reproduction.

Subsequently, the structure of the reproduction system includes a disc 10, an optical pickup 11, a reproduction amplifier 12, a waveform equalizer 13, a shaper 14, a phase locked loop 16, and a discriminator. And a decoder 17.

The signal detected from the photodiode of the optical pickup 11 is amplified by the reproduction amplifier 12. The amplified signal waveform is corrected in the waveform equalizer 13, and the waveform interference is suppressed to achieve high density.

The signal output from the waveform equalizer 13 is shaped by the shaper 14, converted into a pulse signal indicating the presence or absence of a signal, and output to the discriminator 15 and the PLL 16. The PLL 16 generates a synchronization signal synchronized with the basic period of the pulse signal output from the shaper 14, and provides the signal to the discriminator 15, and the discriminator 15 provides the synchronization provided from the PLL 16. The presence or absence of the reproduction pulse signal of the light is detected in the time period determined by using the signal, and finally in the detection window.

The code string thus detected is demodulated by the decoder 17 into a data bit string to reproduce the last recorded data. Here, the regenerative amplifier 12 is designed to increase the SN ratio (signal-to-noise ratio) of the output by limiting the high frequency band of the signal and noise frequency spectrum, or in some cases, to stabilize the regenerative output amplitude. It has AGC (Automatic Gain Control) function.

As described above, when the disc (CD) 10 is recorded and reproduced, and a scratch or the like is generated in the data recording area of the disc 10 on which the data is recorded, the user cannot easily determine it.

In the conventional scratch confirmation method, if a scratch portion is generated in the data recording area during the playback of the disc 10, if a scratch is generated during the reproduction of the program area after reading the lead-in area as described above, it is detected and detected. The scratch generating error message is displayed on the display unit (not shown). Therefore, the user can determine that a scratch has occurred in the disk 10. In other words, scratches are not detected by the user at the beginning of the disc 10 playback, and the scratch portion can be confirmed only when the program area, i.e., the music (sound) data recorded in the data recording area, is reproduced.

As described above, the conventional disc reproducing apparatus cannot reproduce the data recorded in the data recording area at all since the scratches are repeatedly reproduced only when the scratch occurs in the TOC area during disc reproduction. have.

Accordingly, the present invention has been made to solve the above-mentioned problems according to the prior art, and an object of the present invention is to detect the occurrence of a scratch in the TOC area of the disc when the disc is reproduced, and to pick up the pickup at the data end area, Read the no-signal portion of the data recording area while moving to the outermost periphery, display the number of songs on the display, and move the optical pickup to the beginning of the data recording area of the disc to play the audio data recorded in the data recording area of the disc. A disk player is provided.

Another object of the present invention is to provide a disc reproducing method corresponding to the above disc reproducing apparatus.

1 shows each recording area of a general CD.

2 is a block diagram showing a general CD playback system;

3 is a block diagram showing a disc reproducing apparatus according to the present invention;

4A and 4B are waveform diagrams illustrating outputs of an amplifier and a differential circuit unit when a scratch is generated on a disc.

5 is an operation flowchart showing a disc reproducing method according to the present invention.

* Explanation of symbols for main parts of the drawings

20: disc 21: optical pickup

22: amplification section 23: differential circuit section

24: control unit 25: pickup drive unit

26: display unit

A feature of a disc defect detecting apparatus according to the present invention for achieving the above object is a disc reproducing apparatus having an optical pickup, a disc reproducing apparatus having an optical pickup, wherein the TOC recording area of the disc by the optical pickup. An amplifier for amplifying the signal reproduced at a predetermined level; A differential circuit unit for differentiating a signal amplified by the amplifier with respect to a period; An optical pickup driver for driving the optical pickup; A display unit for displaying the number of songs recorded on the disc; The differential circuit unit detects the peak value of the differential signal to determine whether a scratch has occurred on the disc. If a scratch is detected, the optical pickup drive unit provides an optical pickup driving control signal to detect the peak value of the differential signal. END area), and a control unit for controlling the display unit to display the number (number of music) of the unsigned portion of the checked data recording area while the optical pickup is moved to the outermost circumference of the disc.

In addition, a feature of the disc defect detection method according to the present invention is characterized in that the disc reproducing method is provided with the optical pickup, and the disc reproducing method is provided with the optical pickup. Reproducing; Amplifying the reproduced signal by a predetermined level, detecting the peak value by differentiating the amplified signal, and determining whether or not a scratch has occurred in the TOC recording area of the disc according to the detected peak value; If it is determined that a scratch has occurred, checking the non-signal portion of the data recording area of the disk while moving the optical pickup to the outermost circumference (disc END area) of the disk; Displaying the number of songs recorded on the disc for the checked no-signal unit for the user to check; When the display is completed, the optical pickup is moved to the beginning of the data recording area of the disc to play the disc from that point.

Hereinafter, an embodiment of a disc reproducing apparatus and a method thereof according to the present invention will be described with reference to the accompanying drawings.

3 is a block diagram illustrating a disk reproducing apparatus according to the present invention, and FIGS. 4A and 4B are waveform diagrams showing outputs of an amplifier and a differential circuit when a scratch is generated on a disk.

First, referring to FIG. 3, the structure of the disc reproducing apparatus according to the present invention will be described. The disc 20, the optical pickup 21, the amplifier 22, the differential circuit 23, the controller 24, and the pickup driver And a display unit 26.

The optical pickup 11 is composed of a semiconductor laser diode that projects laser light to record input data on the disk 10 and a photodiode that receives light reflected from the disk 10 during reproduction. Here, the signal detected from the photodiode of the optical pickup 21 is applied to the amplifier 22 when the TOC area of the disk 20 is reproduced.

The amplifier 22 amplifies a reproduction signal of the TOC region of the disk provided by the optical pickup 21 at a predetermined level and outputs the differential signal to the differential circuit unit 23. The differential circuit unit 23 is amplified by the amplifier 22. The waveform of the given signal is differentiated with respect to the period. When the differential waveform is applied to the control unit 24 as described above, the control unit 24 determines whether the disk 20 is scratched, provides a drive control signal to the pick-up driving unit 25, and provides a pick-up driving unit ( 25 controls the optical pickup 21 according to the drive control signal provided from the controller 24.

The display unit 26 displays the number of songs recorded on the disc 21 as the optical pickup 21 is driven.

The operation of the disc reproducing apparatus according to the present invention having the configuration as described above will be described.

First, data recorded in the TOC area of the disc 20 is reproduced by the optical pickup 21. Here, the signal to be reproduced is a signal with respect to the time of the grain number and the total grain number. The reproduction signal thus reproduced is amplified by the amplifier 22 to a predetermined level for reproduction of the audio data and output to the differential circuit unit 23. At this time, if a scratch occurs in a predetermined section of the TOC region of the disk 20 of the signal amplified by the amplifier 22, the output waveform of the amplifier 22 is generated as shown in Figure 4a.

When the waveform shown in FIG. 4A output from the amplifier 22 is differentiated in the differential circuit unit 23, the differential waveform of the scratch generating part is displayed as shown in FIG. 4B.

In this way, when the differential signal from the differential circuit unit 23 is applied to the control unit 24, the control unit 24 determines whether or not a scratch has occurred in the reproduced signal, that is, the TOC area of the disc 20. As a result of the determination, if the peak value as shown in FIG. 4B is continuously detected for a predetermined time, it is determined that a scratch has occurred in the TOC region of the disk 20 (non-playback), and the pickup driving control signal is provided to the pickup driving unit 25. do.

The pickup driving unit 25 moves the optical pickup 21 to the end region (END AREA) B of the outermost circumference of the disc 20 in accordance with the pickup driving control signal provided from the control unit 24. In this way, the optical pickup 21 is moved to the outermost end of the disk 21 by the driven driver 25 while detecting the non-signal portion of the data recording area of the disk 20. Here, the no-signal part of the disc 20 means a signal of a part where one song ends and a part where another song starts.

As such, the signal-free signal detected as the optical pickup 21 is moved is applied to the controller 24 through the amplifier 22 and the differential circuit unit 23. The controller 24 counts the number of no-signals applied by the optical pickup 21 until the optical pickup 21 is moved to the outermost peripheral region of the disc 20, and displays the number, that is, the number of curves. It is displayed on the part 26.

In this way, the display unit 26 displays the number of songs, and at the same time, the control unit 24 provides a drive control signal to the pickup driving unit 25 so that the optical pickup 21 ends at the end of the TOC area shown in FIG. It moves to the beginning of the area (S).

When the optical pickup 21 moves to the start portion S of the data recording area, audio data recorded in the data recording area is reproduced from that point. Therefore, even if a scratch occurs in the TOC area of the disc 20, the audio data of the disc 20 is reproduced.

A disc production method corresponding to the operation of the disc reproducing apparatus according to the present invention as described above will be described with reference to FIG.

5 is an operational flowchart showing a method of playing a disc according to the present invention.

First, after turning on the power of the disc reproducing system, the disc 20 is inserted (S101). Subsequently, a CD function key is selected, and a disc 20 playback key input signal is provided (S102).

When the reproduction key input signal is input, the optical pickup 21 starts reproduction from the TOC area of the disc 20 (S103), and the signal reproduced by the optical pickup 21 is applied to the amplifying unit 22. The amplified signal is amplified by a predetermined width, and the amplified signal performs differentiation with respect to a period in the differential circuit unit 23.

Subsequently, when the peak value is detected from the differentiated waveform and applied to the control unit 24, the control unit 24 determines whether or not a scratch has occurred in the data recording area of the disk 20 according to the applied peak value (S104). Here, the determination of whether or not the scratch is generated is determined by the signal waveform as shown in FIG. 4B differentiated by the differential circuit unit 23.

If it is determined that no scratch is generated in the disk 20, the disk 20 is normally played back. If it is determined that a scratch has occurred in the disk 20, the control unit 24 sends the optical pickup 21 to the pickup driver 25. A control signal is provided to move the optical pickup 21 to the outermost circumference of the disc 20 (END area: part B of FIG. 3) and check the number of no signal parts of the data recording area (S105).

When the movement to the outermost circumference (END area) B of the disk 20 is completed while checking the number of sub-signals in the data recording area, the control unit 24 sends the display unit 26 the number of songs corresponding to the checked non-signal unit. Simultaneously with display, the optical pickup 21 is driven to move to the beginning S of the data recording area (S107). Here, the display of the number of music may be displayed after the optical pickup 21 is completed to move to the start portion S of the data recording area.

When the optical pickup 21 completes the movement to the beginning of the data recording area of the disc 20, audio data recorded in the data recording area is reproduced from that time (S108).

Disc playback apparatus and method thereof according to the present invention detect a defect (scratch) in a TOC recording area when a disc is played back, and if a scratch is detected, move the optical pickup to the outermost circumference of the disc, and perform no signal in the data recording area. By checking the unit, the number of songs for the checked non-signal unit is displayed and the optical pickup is moved to the beginning of the data recording area to play the disc. Even if a scratch occurs on the disc, the disc is continuously played in the same manner as the normal play of the disc. It has the effect of playing back audio data.

In addition, even if a scratch is generated, the disc can be reproduced using such a device, thereby improving the performance of the disc reproducing apparatus and the reliability of the product.

Claims (3)

In a disc reproducing apparatus provided with an optical pickup, An amplifier for amplifying a predetermined level of a signal reproduced in the TOC recording area of the disc by the optical pickup; A differential circuit unit for differentiating a signal amplified by the amplifier with respect to a period; An optical pickup driver for driving the optical pickup; A display unit for displaying the number of songs recorded on the disc; The differential circuit unit detects the peak value of the differential signal to determine whether a scratch has occurred on the disc. If a scratch is detected, the optical pickup drive unit provides an optical pickup driving control signal to detect the peak value of the differential signal. END area), and a control unit for controlling the display unit to display the number (number of music) of the unsigned portion of the checked data recording area while the optical pickup is moved to the outermost circumference of the disc. Disc player. The optical pickup of claim 1, wherein the control unit provides the number of grains to the display unit and provides a drive control signal to the optical pickup driving unit so that the optical pickup is moved to the start portion S of the data recording area of the disc, and the optical pickup is performed. And reproducing the audio data recorded in the data recording area from that time when the movement to the beginning of the recording area is completed. In the disc playback method provided with the optical pickup, Reproducing the signal recorded in the TOC recording area of the disc by the optical pickup; Amplifying the reproduced signal by a predetermined level, detecting the peak value by differentiating the amplified signal, and determining whether or not a scratch has occurred in the TOC recording area of the disc according to the detected peak value; If it is determined that a scratch has occurred, checking the non-signal portion of the data recording area of the disk while moving the optical pickup to the outermost circumference (disc END area) of the disk; Displaying the number of songs recorded on the disc for the checked no-signal unit for the user to check; And when the display is completed, moving the optical pickup to the beginning of the data recording area of the disc and playing the disc from that point.

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