KR100268382B1 - Defect compensator of an optical disc - Google Patents

Abstract

PURPOSE: A compensating device for defect of an optical disk is provided to eliminate an impulse signal caused by a discontinuous servo error signal generated is front and rear portions of a defect detecting section. CONSTITUTION: A defect detect unit(30) detects defect on an optical disk for generating a second defect detect signal having a larger defect detect section than a first defect detect section while including a first defect detect signal and the first defect detect section. A servo control unit receives first and second defect detect signals for outputting first and second control signals corresponding to the defect detect signals. An average signal generate unit(32c) generates an average signal for a servo error signal according to the first control signal of the servo control unit. A compensating unit(34) receives an output of the average signal generate unit while compensating for a gain of established compensating variable according to the second control signal.

Description

Fault compensator of optical disc

The present invention relates to an apparatus for compensating for a servo error signal when a defect of an optical disc is detected.

Optical disc recording / playback apparatuses are widely used for multimedia such as audio, video, and other digital data in optical discs such as CDs (Compact Discs) or DVDs (Digital Versatile Discs) because of their recording capacity and fast access time. have. In particular, DVDs, which have appeared since the mid 90s, have a storage capacity of 4.7GB on one side, which makes it possible to record / play back 2 hours of movies that were difficult to store in the clear picture quality of MPEG2. .

In general, an optical disc recording / reproducing apparatus has a feature of reproducing a signal by a large and small reflection amount using a non-contact optical head. Since the optical disc recording / reproducing apparatus especially uses a non-contact optical head, it is possible to prevent quality deterioration as compared to a recording medium such as a tape using a contact head, and exhibits a relatively strong reproducing ability against dust and scratches on the surface of the optical disc.

On the other hand, when the optical disk storage medium is not stored in the cartridge, various physical defects are more likely to occur on the reproduction surface or the opposite surface in the process of use than when the optical disk storage medium is stored in the cartridge. Such defects may include scratches on the surface of the disk, fingerprints, droplets, black-dots, pin-hole defects through the laser beam, and disk manufacturing processes. There are defects such as interruption (a form in which some sections of the data surface recorded on the disk are missing).

These defects not only distort or omit the reproduction signal due to the defect, but also cause the servo signal essential for signal reproduction to malfunction, thereby making it impossible or obstructing the signal reproduction after the defect, thereby greatly affecting the optical disc recording / reproducing apparatus. Therefore, it is common for an optical disc recording / reproducing apparatus to incorporate a defect detecting apparatus and to operate a compensating apparatus for a specific defect whenever it is detected.

1 is a block diagram showing each configuration of a conventional optical disc defect compensator. The apparatus of FIG. 1 includes a defect detection unit 10 and an average value signal generation unit 12. The defect detection unit 10 generates and outputs a defect detection signal when a defect is detected from the reproduction signal of the optical disc. This defect detection signal has a high level in a defect detection section and a low level in a section in which no defect is detected. On the other hand, the average value signal generation unit 12 including a low pass filter receives the servo error signal and generates and outputs a low frequency average value signal. At this time, the servo error signal SES is a focusing error signal FES for focusing servo control or a tracking error signal TES for tracking servo control.

Meanwhile, the optical disc defect compensator of FIG. 1 includes a switch 14 to receive the signals output from the above-described servo error signal and the average value signal generator 12, respectively, and receive the signals corresponding to the above-described defect detection signals. Output the signal selectively. In more detail, when the defect detection signal is in a defect detection state, the switch 14 considers that a servo error signal generated in this section, that is, a focusing error signal or a tracking error signal is not reliable as an error signal for servo control. The servo error signal received in the section is replaced with a low frequency average value signal. Since the above-described output signal of the average value signal generator 12 is a low frequency signal of several tens to several Hz, it is possible to eliminate the signal generated in the defect detection section. The apparatus of FIG. 1 has a compensator 16 connected to the output of the switch 14 described above. The compensator 16 performs a predetermined compensation process for stabilizing servo control, i.e., phase compensation, on the signal received from the switch 14, and then outputs the compensated signal.

2 is a signal processing diagram of the conventional apparatus of FIG. The servo error signal shown in FIG. 2 is difficult to use as an error signal for servo control due to distortion or omission of a signal in a section in which a defect of an optical disc is detected. Therefore, the conventional optical disk defect compensator replaces the servo error signal in the section in which the defect is detected with a low frequency average value signal, and makes stable servo control by performing a predetermined compensation process for stabilizing the servo control. do.

In particular, if the defect detection section of the optical disc contained in the defect detection signal is too short or too long in comparison with the actual defect section, it has a great influence on the servo control. Therefore, the conventional defect detection section replaces the received servo error signal with a low frequency average value signal. The servo control state becomes the most stable.

However, in the conventional optical disc defect compensator, there are differences depending on the method of generating the servo error signal, but the state of the servo error signal before and after the defect detection section exits the signal and defect detection section generated at the entrance of the defect detection section. The signals generated along the way have discontinuous characteristics. When such a discontinuous servo error signal is input to the compensator, an impulse signal may be output depending on the differential characteristics inside the compensator. Such an impulsive signal has a problem of making stable servo control difficult by causing an abnormal reaction to an actuator of an actuator for servo control.

SUMMARY OF THE INVENTION An object of the present invention for solving this problem is to generate a second fault detection signal that is detected more broadly, including a fault detection interval of the first fault detection signal, to adjust the gain of the servo error signal input to the compensator, or An optical disc defect compensation device for eliminating or suppressing an impulse signal caused by a discontinuous servo error signal generated before and after a conventional defect detection section by different compensation processes is provided.

1 is a block diagram showing each structure of a conventional optical disc defect compensator.

2 is a signal processing diagram of FIG.

3 is a block diagram showing each configuration of an optical disc defect compensation apparatus according to the present invention.

4 is a detailed configuration diagram of the gain adjusting unit of FIG. 3, and FIG. 4A is a case where gain is adjusted over the entire band of the servo error signal, and FIG. 4B is a detail when gain is adjusted only for a predetermined high frequency band of the servo error signal. Diagram.

5 is a configuration diagram showing yet another configuration of the gain adjustment and average value signal generating means of FIG.

6 is a timing diagram of first and second defect detection signals in accordance with the present invention.

7 is a block diagram showing each configuration of another optical disc defect compensation apparatus according to the present invention.

8 is a configuration diagram showing another configuration of the compensation means of FIG.

9A-9B are views for explaining FIG. 4;

<Explanation of symbols for main parts of drawing>

10,30,70: defect detection unit 12,32c, 74b: average signal generation unit

14, 32b, 32d, 74a, 74c, 76c: switch 16, 34: compensator

32: gain adjustment and average signal generation means 32a: gain adjustment unit

72: servo control unit 74: mean value signal generating means

76: compensation means 76a, 76b, 76d: compensator

An optical disc defect compensating apparatus of the present invention for achieving the above object includes a second detection section having a defect detection section that detects a defect of an optical disc and includes a detection section of the first defect detection signal and the first defect detection signal, and has a wider detection section. A defect detection unit generating a defect detection signal and outputting each of them; Gain adjustment and average value signal generation means for generating a gain adjustment and an average value signal selectively for the servo error signal described above and outputting the same according to the defect detection states of the first and second defect detection signals of the above-described defect detection unit; And a compensator which receives the outputs of the above-described gain adjustment and average value signal generating means, performs a predetermined compensation process for stabilizing the servo control, and outputs a compensated signal.

Another optical disc defect compensating apparatus of the present invention for achieving the above object comprises a first detection section having a defect detection section that detects a defect of an optical disc and includes a detection section of the first defect detection signal and the first defect detection signal, and which has a wider detection section. A defect detection unit for generating two defect detection signals and outputting them respectively; A servo control unit which receives the first and second defect detection signals described above, and outputs a first control signal corresponding to the received first defect detection signal and a second control signal corresponding to the second defect detection signal; An average value signal generating means for selectively generating and outputting an average value signal with respect to the above-described servo error signal according to the first control signal of the above-described servo controller; And compensation means for receiving the output of the above-described average value signal generating means and compensating for gain by selecting one of preset compensation variables for stabilizing the servo control according to the second control signal from the servo controller. .

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

3 is a block diagram showing each configuration of an optical disk defect compensation apparatus according to an embodiment of the present invention. The optical disc defect compensator of FIG. 3 includes a defect detection unit 30 and a gain adjustment and average value signal generation means 32. As shown in FIG. The defect detection unit 30 detects a defect of the optical disc and includes a defect detection section of the first defect detection signal d1 and the first defect detection signal d1, and has a second defect detection signal having a wider detection section. (d2) is generated, and each of the generated defect detection signals is output. Further, the gain adjusting and average value signal generating means 32 shown in the apparatus of FIG. 3 is received in accordance with the defect detection states of the first and second defect detection signals d1 and d2 from the defect detection unit 30 described above. A gain adjustment and an average value signal are selectively generated with respect to the servo error signal, and output.

In more detail, the gain adjustment and average signal generation means 32 of FIG. 3 is provided with the gain adjustment part 32a. The gain adjusting unit 32a lowers the gain of the servo error signal to a predetermined size when the second defect detection signal d2 described above is in the defect detection state, and outputs the gain down signal. The detailed block diagram of the gain adjustment part 32a can be comprised as shown in FIG. FIG. 4A illustrates a case in which the gain is down to a predetermined size over the entire band of the received servo error signal, and FIG. 4B illustrates a case in which the gain is adjusted only for a high frequency band of a predetermined cutoff frequency of the servo error signal. The servo error signal passing through the above-described gain adjusting section 32a is reduced in magnitude as shown in FIG. FIG. 9A shows that when the gain adjusting unit 32a has the configuration as shown in FIG. 4A, the gain is down to the size of 1 / K (K> 1) over the entire frequency band of the servo error signal. 9B shows that the gain is decreased for a high frequency band of a predetermined cutoff frequency f1 of the servo error signal when the gain adjusting unit 32a has the configuration as shown in FIG. 4B. In addition, the average value signal generation section 32c of the gain adjustment and average value signal generation means 32 receives the above-described output signal of the gain adjustment section 32a to generate a low-frequency average value signal of several tens of Hz, and generates the generated low frequency average value. Output the signal. In this case, the average signal generator 32c may be implemented using a low pass filter (LPF). Subsequently, the gain adjusting and average value signal generating means 32 is provided with a first switch 32d. The first switch 32d receives the output signal of the gain adjustment section 32a and the output signal of the average value signal generation section 32c, respectively, and the first defect detection signal d1 from the defect detection section 30 is in a defect detection state. In this case, the signal received from the average value signal generation section 32c is outputted, and if the first defect detection signal d1 is not in a defect detection state, the signal received from the gain adjustment section 32a is outputted. In this case, the gain adjusting and average value signal generating means 32 may further include a second switch 32b between the gain adjusting portion 32a and the average value signal generating portion 32c. The second switch 32b receives the above-described output signal of the gain adjusting unit 32a, and if the first defect detection signal d1 from the defect detection unit 30 is in a defect detection state, the received signal is an average value signal generation unit ( Block supply to 32c). When the second switch 32b is further provided, the average value signal generation unit 32c generates a low frequency average value signal from a signal received before the first defect detection signal d1 is in a defect detection state, and holds it. The low frequency average value signal is supplied to the first switch 32d.

On the other hand, the gain adjusting and average signal generating means 32 of the apparatus of FIG. 3 may be configured as shown in FIG. The function of each configuration of the gain adjustment and average value signal generation means 32 shown in FIG. 5 performs the same function as that of each configuration of the gain adjustment and average value signal generation means 32 shown in FIG. The only difference is that the gain adjusting section 32a is connected to the output terminal of the first switch 32d.

More specifically, the average value signal generator 32c of FIG. 5 receives the servo error signal to generate a low frequency average value signal, and outputs the generated low frequency average value signal. The first switch 32d of FIG. 5 receives the above-described output signal of the servo error signal and the average value signal generator 32c, and the first defect detection signal d1 from the defect detection unit 30 is in a defect detection state. In this case, the signal received from the above-described average value signal generation unit is output, and if the first defect detection signal d1 is not in the defect detection state, the received servo error signal is output. The signal output from the first switch 32d is input to the gain adjusting section 32a. The gain adjusting section 32a down-gains the received signal to a predetermined size and outputs it. At this time, as shown in Fig. 4, the gain adjusting unit 32a can be configured so that the gain can be down only for the entire band or the predetermined high frequency band. In this case, the gain adjusting and average value signal generating means 32 may further include a second switch 32b in front of the average value signal generating portion 32c. The second switch 32b receives the servo error signal, and blocks the received signal from being supplied to the average value signal generator 32c when the first defect detection signal d1 from the defect detection unit 30 is in a defect detection state. do.

The apparatus of FIG. 3 also comprises a compensator 34 connected to the output of the gain adjustment and average signal generation means 32 having the above-described configurations. The compensator 34 receives the output signal of the gain adjustment and the average value signal generating means 32, performs a predetermined compensation process for stabilizing the servo control, and then outputs the compensated signal as the servo control signal. At this time, when the defect of the optical disc is not detected, the compensator 34 receives a general servo error signal from the above-described first switch 32d and performs phase compensation for stabilizing the servo control. On the other hand, when the defect of the optical disc is detected, the compensator 34 receives a signal of which the gain of the servo error signal is lowered from the above-described first switch 32d, replaced with a low frequency average value signal, and predetermined for the received signal. Will be compensated for. 3 to 5 having such a configuration will be described in more detail with reference to FIG. 6.

FIG. 6 is a diagram illustrating the timing of the first defect detection signal d1 and the second defect detection signal d2 generated in the defect detection unit 30 according to the present invention. The defect detection unit 30 according to the present invention generates the aforementioned first defect detection signal d1 and the second defect detection signal d2 by using different reference levels. In this case, the defect detection signals generated by the defect detection unit 30 have a high level in a section in which a defect of the optical disc is detected, and a low level in a section in which a defect is not detected. The first defect detection signal d1 is used to determine whether to replace the received servo error signal with a low frequency average value signal in the defect detection section in the same manner as the defect detection signal used in the conventional optical disc defect compensator. The second defect detection signal d2 according to the present invention is used to bring down the gain of the servo error signal input to the compensator 34. More specifically, the servo error signal is input to the compensator 34 as a normal servo error signal when the first fault signal is not in the defect detection state, and is replaced by the low frequency average value signal when the servo error signal is changed into the defect detection state. do. At this time, the servo error signal input to the compensator 34 has a discontinuous characteristic as it enters the defect detection section shown in the first defect detection signal d1 and exits the defect detection section. The servo error signal having this characteristic is output as an impulse signal while passing through the compensator 34, which causes an abnormal reaction to the actuator of the driver. Accordingly, the above-described method is performed by lowering the gain of the servo error signal input to the compensator 34 by the second defect detection signal d2 including the defect detection section of the first defect signal and having a wider defect detection section to a predetermined magnitude. It can suppress or eliminate the generation of an impulsive signal.

The second defect detection signal d2 used for this purpose should be generated as a detection signal having a wider defect detection section while including the defect detection section of the first defect detection signal d1, as shown in FIG. In order to satisfy this condition, the defect detection unit 30 must be configured such that t ₁ and t ₂ shown in FIG. 6 always have zero or more values. t ₁ and t ₂ are experimentally determinable values and are affected by the structure of the optical system and the like. The first defect detection signal d1 and the second defect detection signal d2 having the above characteristics are generated and output by the defect detection unit 30 of FIG. 3.

Meanwhile, the apparatus of FIG. 3 accurately focuses a tracking error signal for tracking servo control or a focus of the optical beam generated by the optical pickup device on the pit of the optical disk surface for tracking servo control for accurately following the optical beam generated by the optical pickup device to the center column of the track. A servo error signal such as a focusing error signal for focusing servo control is received. The received servo error signal is input to the gain adjusting section 32a. The gain adjusting unit 32a passes the received servo error signal as it is without gain adjustment in the non-detection state of the second defect detection signal d2 described above. On the other hand, when the gain adjusting unit 32a indicates that the above-described second defect detection signal d2 is in a defect detection state, the gain adjusting unit 32a outputs the gain of the received servo error signal to a predetermined magnitude and outputs it from the compensator 34 described above. Suppresses or eliminates the signal being impulsive in nature. The signal output from the gain adjusting section 32a is input to the average value signal generating section 32c. The average value signal generator 32c generates a low frequency average value signal from the input signal. On the other hand, the first switch 32d selects the signal received from the gain adjusting unit 32a or the signal received from the average value signal generation unit 32c according to the first defect detection signal d1 from the defect detection unit 30. To print. At this time, the first switch 32d outputs a signal received from the gain adjusting unit 32a when the first defect detection signal d1 is not in a defect detection state, and an average value signal when the first defect detection signal d1 is in a defect detection state. The low frequency average value signal received from the generation unit 32c is output to the compensator 34. The compensator 34 stabilizes the servo control by outputting a predetermined compensation process such as phase compensation on the received signal.

Meanwhile, the apparatus of FIG. 3 may further include a second switch 32b to block the signal entering the average value signal generator 32c when the first defect detection signal d1 is in a defect detection state. At this time, the average value signal generation unit 32c receives the servo error signal passing through the gain adjusting unit 32a before the first defect detection signal d1 is in the defect detection state, generates a low frequency average value signal, and is held. The low frequency average value signal is output.

In addition, the apparatus of FIG. 3 can configure the above-described gain adjustment and average value signal generating means 32 as shown in FIG. In this case, the apparatus of FIG. 5 lowers the gain of the servo error signal replaced by the low frequency average value signal by the first defect detection signal d1 by the second defect detection signal d2. The difference between the apparatus of Figs. 3 and 5 is a difference in the coupling order of the gain adjusting section 32a, and there is no difference in the technical meaning.

7 is a block diagram showing each configuration of another optical disk defect compensation apparatus according to an embodiment of the present invention. The optical disc defect compensator shown in Fig. 7 uses the same implementation concept as the optical disc defect compensator shown in Fig. 3, and is an apparatus useful for digital servo control provided with a separate servo controller 72. In detail, the apparatus of FIG. 7 generates the first and second defect detection signals d1 and d2 having the same function as that of FIG. That is, the first defect detection signal d1 is used to determine whether to replace the received servo error signal with a low frequency average value signal in the defect detection section, and the second defect detection signal d2 is output from the compensation means 76. It is used to suppress or eliminate the generation of a signal having impulsive characteristics in the signal. However, although the second defect detection signal d2 is used to determine whether to lower the gain of the servo error signal input to the compensator 34 in the apparatus of FIG. 3, the second defect detection signal d2 is provided with a separate servo controller 72. Is used as a control signal for different compensation variables of one compensator 76d or as a control signal for selecting signals output from different compensators 76a and 76b having different compensation variables. different.

First, referring to FIG. 7, the defect detection unit 70 has the same function and configuration as the defect detection unit 30 of FIG. 3. The first and second defect detection signals d1 and d2 generated by the defect detection unit 70 are input to the servo control unit 72, respectively. The servo controller 72 configured as a microcomputer or a controller outputs the first control signal c1 corresponding to the received first defect detection signal d1 and corresponds to the second defect detection signal d2. The second control signal c2 is output. The average value signal generating means 74 of the apparatus of Fig. 7 generates and outputs a low frequency average value signal selectively with respect to the received servo error signal in accordance with the first control signal c1 of the servo controller. The mean value signal generating means 74 comprises an average value signal generating portion 74b and a first switch 74c having the same function and configuration as the apparatus of FIG. In addition, the apparatus of FIG. 7 further includes the same second switch 74a as that of the apparatus of FIG. 3 to block the servo error signal inputted to the average value signal generator 74b according to the state of the first defect detection signal d1. Can be. At this time, in the case of digital servo control, even if the second switch is not provided, the same effect as in the case where the second switch is provided can be obtained unless the input of the average value signal generation unit is calculated under software control. The signal output from the mean value signal generating means 74 is input to the compensating means 76.

The compensating means 76 of the apparatus of FIG. 7 is provided with different compensators 76a and 76b having different compensation variables for stabilization of the servo control, and to the second control signal c2 of the servo control unit 72. Accordingly, the third switch 76c selectively outputs the signal received by the compensators 76a and 76b described above. In detail, the first compensator 76a of the compensating means 76 is a compensation variable corresponding to when the second defect detection signal d2 is not in the defect detection state. A predetermined compensation process is performed and output. In addition, the second compensator 76b of the compensating means 76 is a compensating variable corresponding to when the second defect detection signal d2 is in a defect detection state. Process and output In this case, the second compensator 76b pre-stores compensation variables having a compensation function for suppressing or eliminating an impulsive output in addition to a predetermined compensation processing function for stabilizing the servo control of the first compensator 76a. Output signals of the first and second compensators 76a and 76b of the compensating means 76 are respectively input to the third switch 76c. The third switch 76c selects and outputs the output of the first compensator 76a when the second control signal c2 corresponding to the case where the second defect detection signal d2 is not in the defect detection state is applied. When the second control signal c2 corresponding to the defect detection state of the second defect detection signal d2 is applied, the output of the above-described second compensator 76b is selected and output.

Meanwhile, the compensating means 76 of the apparatus of FIG. 7 may be configured as shown in FIG. Another compensating means of the FIG. 8 device has one compensator 76d. At this time, the servo controller 72 further has compensation variables corresponding to the first and second compensators 76a and 76b of the apparatus of FIG. 7 described above, and when the second defect detection signal d2 is received, the servo controller 72 enters into a defect detection state. The corresponding compensation variables are output to the compensator 76d of FIG. In detail, when the second defect detection signal d2 received by the servo controller 72 is not in the defect detection state, compensation variables corresponding to the first compensator 76a of the apparatus of FIG. 7 are output as a control signal, and the defect detection state is detected. In this case, compensation variables corresponding to the second compensator 76b of the apparatus of FIG. 7 are output as a control signal. The control signal having the respective compensation variables output from the servo controller 72 is input to the compensator 76d of the apparatus of FIG. The compensator 76d performs a predetermined compensation process on the signal received from the mean value signal generating means 74 with different compensation variables applied. Thus, the apparatus of FIG. 8 having one compensator 76d and a servo control unit 72 storing further compensation variables, has two compensators 76a, 76b and a third which pre-store different compensation variables. The object of the present invention can be achieved much more simply and efficiently than the compensating means 76 of FIG. 7 with the switch 76c.

The optical disc defect compensating apparatus of the present invention generates a second defect detection signal that is detected more broadly, including a defect detection section of the first defect detection signal and the first defect detection signal, and generates a defect detection section by the first defect detection signal. The servo error signal is replaced with a low frequency average value signal, and the gain of the signal input to the compensator is reduced by the second defect detection signal or the compensation variables of the compensator are different. Accordingly, the optical disc defect compensating apparatus of the present invention provides the effect of enabling more stable servo control by suppressing or eliminating the impulsive output of the compensator due to the defect of the optical disc as much as possible by the second defect detection signal described above.

Claims (18)

An apparatus for compensating for a servo error signal received when a defect of an optical disc is detected, the apparatus comprising: detecting a defect of an optical disc and having a wider defect detection section including a detection section of a first defect detection signal and a first defect detection signal; A defect detection unit generating a second defect detection signal and outputting each of them; Gain adjustment and average value signal generation means for selectively generating a gain adjustment and an average value signal for the servo error signal and outputting the signal according to the first and second defect detection signals of the defect detection unit; And a compensator for receiving the outputs of the gain adjustment and the average value signal generating means to perform a predetermined compensation process for stabilization of the servo control, and output a compensated signal. The apparatus of claim 1, wherein the servo error signal is a signal for focusing servo control. The apparatus of claim 1, wherein the servo error signal is a signal for tracking servo control. The method of claim 1, wherein the defect detection unit generates a first defect detection signal and a second defect detection signal by using different reference levels, and the defect detection signals have different levels indicating that the defect detection section and the defect detection section are not detected. Optical disc defect compensation device having a signal. 2. The gain control apparatus according to claim 1, wherein the gain adjusting and average signal generating means downgrades the gain of the servo error signal to a predetermined magnitude when the second defect detection signal is in a defect detection state, and outputs a gain down signal. Adjusting unit; An average value signal generation unit which receives the output signal of the gain adjustment unit to generate an average value signal and outputs the average value signal; And an output signal of the gain adjusting unit and an output signal of the average value signal generating unit, respectively, and outputs a signal received from the average value signal generating unit when the first defect detection signal is in a defect detection state, and wherein the first defect detection signal is And a first switch for outputting a signal received from the gain adjusting unit when the defect is not detected. The optical disc defect compensating apparatus according to claim 5, wherein the gain adjusting unit is configured to bring down the gain so that the state of the servo error signal has a continuous characteristic before and after a defect detection section over the entire band of the received servo error signal. 6. The optical disc defect compensation according to claim 5, wherein the gain adjusting unit reduces the gain so that the state of the servo error signal has a continuous characteristic before and after a defect detection section only for a high frequency band equal to or higher than a predetermined cutoff frequency of the received servo error signal. Device. 6. The apparatus of claim 5, wherein the gain adjusting and average signal generating means receives an output signal of the gain adjusting unit and blocks the received signal from being supplied to the average signal generating unit when the first defect detecting signal is in a defect detecting state. Optical disc defect compensation device further comprises a switch. 2. The apparatus of claim 1, wherein the gain adjusting and average value signal generating means comprises: an average value signal generation unit which receives the servo error signal to generate an average value signal and outputs the average value signal; And receiving output signals of the servo error signal and the average value signal generator, respectively, and outputting a signal received from the average value signal generator when the first defect detection signal is in a defect detection state, and detecting the first defect detection signal as non-defective. A first switch configured to output the servo error signal when in a state; And receiving the signal output from the first switch, and if the second defect detection signal is in a defect detection state, down the gain to a predetermined magnitude so that the state of the received signal has a continuous characteristic before and after the defect detection section. An optical disc defect compensation device including a gain adjusting unit for outputting down. 10. The apparatus of claim 9, wherein the gain adjustment and average signal generation means receives the servo error signal, and if the first defect detection signal is in a defect detection state, shuts off a second switch that blocks the received signal from being supplied to the average value signal generation unit. Optical disc defect compensation device further comprising. An apparatus for compensating for a servo error signal received when a defect of an optical disc is detected, the apparatus comprising: detecting a defect of an optical disc and having a wider defect detection section including a detection section of a first defect detection signal and a first defect detection signal; A defect detection unit generating a second defect detection signal and outputting each of them; A servo control unit for receiving the first and second defect detection signals, respectively, and outputting a first control signal corresponding to the received first defect detection signal and a second control signal corresponding to the second defect detection signal; Average value signal generating means for selectively generating and outputting an average value signal with respect to the servo error signal in accordance with a first control signal from the servo control unit; And compensation means for receiving the output of the average value signal generating means and compensating for gain by selecting one of preset compensation variables for stabilization of servo control according to the second control signal from the servo controller. Fault Compensation Device. 12. The apparatus of claim 11, wherein the servo error signal is a signal for focusing servo control. 12. The apparatus of claim 11, wherein the servo error signal is a signal for tracking servo control. 12. The method of claim 11, wherein the defect detection unit generates a first defect detection signal and a second defect detection signal by using different reference levels, and the different levels indicating that the defect detection signals are a defect detection section and a non-defect detection section. Optical disc defect compensation device having a signal. 12. The apparatus of claim 11, wherein the mean value signal generating means comprises: an mean value signal generation unit for receiving the servo error signal to generate and output an average value signal; And receiving outputs of the servo error signal and the average value signal generator, respectively, and if the first control signal from the servo controller is a control signal corresponding to the defect detection state of the first defect detection signal, received from the average signal generator. And a first switch for outputting a signal and outputting the servo error signal if the first control signal is a control signal corresponding to a defect free detection state of the first defect detection signal. 12. The apparatus of claim 11, wherein the compensation means comprises a first compensator and a second compensator for differently performing compensation processing for stabilizing servo control with respect to a signal received from the average value signal generating means. And a third switch for receiving the signals output from the second compensator and selectively outputting the received signals according to the second control signal. 17. The method of claim 16, wherein the first compensator performs a compensation process corresponding to a defect free detection state of the second defect detection signal, and the second compensator performs a compensation process corresponding to a defect detection state of the second defect detection signal, The third switch outputs a signal received from the first compensator if the second control signal supplied from the servo controller is a control signal corresponding to a defect free detection state of the second defect detection signal, and receives the received second control. And outputting the signal received from the second compensator if the signal is a control signal corresponding to a defect detection state of the second defect detection signal. 12. The method of claim 11, wherein the servo control unit pre-stores predetermined different compensation variables required for the compensation means, and each of the compensation variables corresponding to a defect detection state and a non- defect detection state of the second defect detection signal are respectively stored. Outputs as a control signal, and the compensation means includes a compensator to select one of the pre-stored compensation variables for stabilizing servo control on the signal received from the average value signal generating means according to the second control signal. Optical disc defect compensation device to compensate for gain.

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