JP2004087054A - Optical disc reproducing apparatus and phase compensation gain adjusting method thereof - Google Patents

Abstract

Provided is an optical disc reproducing apparatus capable of suppressing an increase in gain of a servo DSP at the time of adjusting a phase compensation gain, and preventing a focus servo from deviating due to a track cross signal during a traverse movement.
A servo DSP measures an amplitude value of a focus error signal as a preliminary process at the time of adjusting a phase compensation gain, and the measurement result and data describing an amplitude value for each optical disk prepared in advance and having different reflectances. The type of the optical disk is determined by comparing the table with the table. The input impedance of the driver for driving the focus actuator (actuator coil) is switched in accordance with the result of this determination, the gain of the driver is set to an appropriate value, and the amplitude value of the focus error signal is made to match that of the CDDA. Thereafter, normal phase compensation gain adjustment is performed.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk reproducing apparatus for adjusting a phase compensation gain of a focus servo loop, and a method for adjusting the phase compensation gain.
[0002]
[Prior art]
Recently, with the spread of optical disk recording apparatus records a music CD-R (C ompact D isc R ecordable) or CD-RW (C ompact D isc R e w ritable) their own preferences to a writable optical disc such as More and more users are enjoying it. However, at present, because there is no reproducing apparatus dedicated to the writable optical disk, the reproduction of such an optical disk, normal music CD (CDDA; C ompact D isc D igital A udio) optical disc reproducing for reproducing The device is used.
[0003]
Hereinafter, a conventional optical disk reproducing apparatus for CDDA reproduction will be described. FIG. 2 is a diagram schematically showing a servo system in a conventional optical disc reproducing apparatus. In FIG. 2, reference numeral 1 denotes an optical disk, and 2 denotes an optical pickup that irradiates the optical disk 1 with laser light and converts the reflected light into a current signal. The optical pickup adjusts a focal position and focuses the laser light. It has a tracking actuator for fine adjustment of the position and a laser diode for emitting laser light. Reference numeral 3 denotes a head amplifier (signal amplifier) which converts a current signal from the optical pickup 2 into a voltage signal and amplifies it at a high frequency, and extracts a focus error signal and a tracking error signal. 4 denotes a servo loop of the device which satisfies a predetermined gain characteristic set phase and gain (gain) of each signal from the head amplifier 3 to the servo DSP (D igital which a drive signal for controlling driving each actuator outputs independently for each occurrence S ignal P rocessor; feedback amplification Adjuster), 5 amplifies each drive signal from the servo DSP 4 in accordance with each actuator and drives each actuator, 6 a spindle motor for rotating the optical disk 1, 7 issues a command to control the servo DSP 4 A microcontroller to control.
[0004]
FIG. 3 is a diagram showing a focus servo loop for keeping the focused state of the laser beam of the optical disk reproducing apparatus. In order to make this focus servo loop a stable amplifier circuit, this device adjusts the phase compensation gain so that the loop gain of the focus servo becomes 0 dB at a frequency of 750 Hz. That is, in the conventional optical disk reproducing apparatus for CDDA reproduction, when the CDDA is mounted, a disturbance of 750 Hz is injected into the focus servo loop with the focus servo turned on, and the open loop gain of the focus servo becomes 0 dB at this frequency. By adjusting the gain of the loop filter (a function related to the focus servo loop of the servo DSP 4), the focus servo loop is a stable amplifier circuit that does not cause oscillation.
[0005]
Thus, in the conventional optical disc reproducing apparatus, the gain of the loop filter (servo DSP) is adjusted so that the open loop gain of the focus servo becomes 0 dB at the frequency of 750 Hz.
[0006]
Next, the traverse movement of the optical pickup in the above-mentioned optical disc reproducing apparatus will be described. When the optical pickup is traversed to the target track, the optical pickup is traversed to the target track by counting track crosses in a state where the focus servo is turned on and the tracking servo is turned off as shown in FIG.
[0007]
That is, when the main beam spot crosses the track as shown in FIG. 5A, irregular reflection of the laser light occurs at the boundary between the groove area and the land area as shown in FIG. As shown, a spot shift occurs on the light receiving element (four-division photodiode) of the optical pickup. Since the signal component of the track cross signal is superimposed on the focus error signal as a result of the spot shift, the track cross signal is extracted from the focus error signal, the track cross is counted, and the traverse movement is controlled. However, in this device, as shown in FIG. 5, focus servo and tracking servo using an astigmatism method and a three-beam method are performed.
[0008]
Subsequently, a re-pull-in operation at the time of traverse movement in the optical disk reproducing apparatus will be described. If the focus is lost during the traverse movement, the servo DSP 4 senses the fact and outputs an out-of-focus signal to the microcontroller 7. Upon receiving the out-of-focus signal, the microcontroller 7 issues a redraw command to the servo DSP 4 (see FIG. 2). The servo DSP 4 outputs a drive signal according to this command, and causes the focus actuator to perform a focus search operation. After focusing, the optical pickup is returned to the deviated address position, and traverse movement is started from there.
[0009]
In the above-described conventional optical disk reproducing apparatus, the phase compensation gain is adjusted in the same manner as in CDDA even when a CD-R or CD-RW is mounted. However, CD-R and CD-RW have a lower reflectance than CDDA, and the amplitude of the focus error signal becomes smaller. Therefore, it is necessary to set a gain value larger than the gain value for CDDA. That is, when an optical disk having a low reflectance such as a CD-R or a CD-RW is mounted, the amplitude of the signal from the optical pickup becomes smaller and the amplitude of the focus error signal from the head amplifier becomes smaller than when the CDDA is mounted. . Therefore, in order to maintain the predetermined gain characteristic (the characteristic that the open loop gain of the focus servo becomes 0 dB at a frequency of 750 Hz), as shown in FIG. 6, the loop filter (servo) is reduced by the reduced gain (-GdB). It is necessary to increase the gain (+ GdB) in the DSP).
[0010]
On the other hand, as shown in FIG. 7, the loop filter has a characteristic that the gain rises steeply in a high frequency region of a frequency of 15 kHz or more. When the gain set in the loop filter increases, the gain of the high frequency region of a frequency of 15 kHz or more naturally increases. The gain also increases accordingly. As described above, when an optical disk having a low reflectance is mounted, a larger gain is set than when the CDDA is mounted. Therefore, the gain in a high frequency region of a frequency of 15 kHz or more is larger than that when the CDDA is mounted. Therefore, when a signal having a frequency of 15 kHz or more is input to the loop filter (servo DSP) when an optical disk having a low reflectance is mounted, the amplitude value of a drive signal obtained by multiplying the gain by the gain becomes equal to or larger than the dynamic range of the servo DSP and is clipped. May be present.
[0011]
Considering the traverse movement when the low-reflectivity optical disk is mounted, the signal component of the track cross signal is superimposed on the focus error signal even when the low-reflection optical disk is mounted, as in the case of mounting the CDDA. However, since the track cross signal is superimposed on the focus error signal at a frequency around 15 kHz, the frequency of the focus error signal during the traverse movement is increased to around 15 kHz. That is, when the focus error signal during the traverse movement is input to the loop filter, as described above, the amplitude value of the drive signal is clipped because it is equal to or larger than the dynamic range of the servo DSP, and as a result, the focus may be lost. is there. Further, when the focus is lost, the above-described re-pulling operation is started, so that there is a problem that the reproduction start time of the optical disk becomes long.
[0012]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems.When a low-reflectance optical disk is mounted, the gain of the driver or the amount of laser power is increased to compensate for the lack of gain of the focus servo loop system. It is an object of the present invention to provide an optical disk reproducing apparatus capable of suppressing a gain increase of a servo DSP at the time of adjusting a phase compensation gain and preventing a focus servo from deviating due to a track cross signal during a traverse movement, and a method of adjusting the phase compensation gain. Aim.
[0013]
[Means for Solving the Problems]
An optical disk reproducing apparatus according to claim 1 of the present invention irradiates an optical disk with a laser beam and converts the reflected light into a current signal, a focusing actuator for focusing the laser beam, and an optical pickup from the optical pickup. A signal amplifier that converts a current signal into a voltage signal, amplifies the signal at a high frequency, and extracts a focus error signal; a focus feedback that sets a gain and a phase of the focus error signal from the signal amplifier and outputs a drive signal of the focusing actuator; An amplification adjuster; and a focus driver that drives the focus actuator by using the drive signal as an input. The phase of the focus servo loop for maintaining a focused state of the laser beam satisfies a predetermined gain characteristic. After adjusting the compensation gain, the gain of the focus feedback amplifier is adjusted. An optical disc reproducing apparatus for setting a gain, wherein a data table in which data of a signal amplitude value of a focus error signal obtained by focusing a laser beam at an initial gain setting for a reference disc is described for each optical disc having a different reflectance. And comparing the data table with a signal amplitude value of a focus error signal obtained by focusing the laser beam on the currently mounted optical disk with the initial gain set, and comparing the data table with the type of the optical disk. Gain adjustment means for adjusting the gain of the focus driver according to the result of the determination, and matching the amplitude of the drive signal in the initial gain setting state with that of the reference disk. Then, the laser light is focused with the initial gain set, and the focus adjustment is performed by the gain adjusting means. After adjusting the gain of the driver, and sets the gain of the focus feedback amplification regulator performs normal phase compensation gain adjustment.
[0014]
According to a second aspect of the present invention, there is provided an optical disk reproducing apparatus that irradiates an optical disk with laser light and converts the reflected light into a current signal, a focusing actuator that focuses the laser light, and an optical pickup from the optical pickup. A signal amplifier that converts a current signal into a voltage signal, amplifies the signal at a high frequency, and extracts a focus error signal; a focus feedback that sets a gain and a phase of the focus error signal from the signal amplifier and outputs a drive signal of the focusing actuator; An amplification adjuster; and a focus driver that drives the focus actuator by using the drive signal as an input. The phase of the focus servo loop for maintaining a focused state of the laser beam satisfies a predetermined gain characteristic. After adjusting the compensation gain, the gain of the focus feedback amplifier is adjusted. An optical disc reproducing apparatus for setting a gain, wherein a data table in which data of a signal amplitude value of a focus error signal obtained by focusing a laser beam at an initial gain setting for a reference disc is described for each optical disc having a different reflectance. And comparing the data table with a signal amplitude value of a focus error signal obtained by focusing the laser beam on the currently mounted optical disk with the initial gain set, and comparing the data table with the type of the optical disk. Laser power adjusting means for adjusting the laser power amount of the laser light in accordance with the result of the determination, and matching the amplitude of the focus error signal in the initial gain setting state to that of the reference disk. When mounted, the laser light is focused with the initial gain set, and the laser power is adjusted by the laser power adjusting means. After adjusting the amount of power, and sets the gain of the focus feedback amplification regulator performs normal phase compensation gain adjustment.
[0015]
According to a third aspect of the present invention, there is provided a method for adjusting a phase compensation gain of an optical disc reproducing apparatus, the phase compensation gain being adjusted so that a focus servo loop system for maintaining a focused state of a laser beam satisfies a predetermined gain characteristic. A phase compensation gain adjustment method for a reproducing apparatus, wherein a laser beam is focused on a currently loaded optical disk while setting an initial gain for a reference disk, and a signal amplitude value of a focus error signal is measured. The result is compared with a data table of the signal amplitude value of the focus error signal for each optical disk having a different reflectance measured and stored in advance based on the initial gain setting to determine the type of the optical disk, and according to the determination result, Adjust the gain of the focus driver that drives the focus actuator by adjusting the initial gain setting After matching the amplitude of the drive signal of the focusing driver to that of the reference disk in, and performs normal phase compensation gain adjustment.
[0016]
According to a fourth aspect of the present invention, there is provided a method for adjusting a phase compensation gain of an optical disc reproducing apparatus, the phase compensation gain being adjusted so that a focus servo loop system for maintaining a focused state of a laser beam satisfies a predetermined gain characteristic. A phase compensation gain adjustment method for a reproducing apparatus, wherein a laser beam is focused on a currently loaded optical disk while setting an initial gain for a reference disk, and a signal amplitude value of a focus error signal is measured. The result is compared with a data table of the signal amplitude value of the focus error signal for each optical disk having a different reflectance measured and stored in advance based on the initial gain setting to determine the type of the optical disk, and according to the determination result, To adjust the amount of laser power to irradiate the optical disk, and adjust the focus error signal in the initial gain setting state. After matching the amplitude to that of the reference disk, and performs normal phase compensation gain adjustment.
[0017]
As described above, according to the present invention, even when an optical disk having a low reflectance is mounted, it is possible to satisfy the gain characteristics of the servo loop and suppress an increase in the gain of the servo DSP at the time of adjusting the phase compensation gain. Thus, it is possible to prevent the focus servo from deviating due to the track cross signal during the traverse movement.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings, focusing on differences from the related art. Note that details of the same items as those in the related art are omitted.
[0019]
(Embodiment 1)
In the optical disc reproducing apparatus according to the first embodiment, the gain of the driver (focus driver) is changed according to the type of the loaded optical disc, so that the phase compensation gain can be adjusted when a low-reflectance optical disc is loaded. An increase in the gain of the servo DSP is suppressed. In other words, the lack of gain of the focus servo system when the optical disk having a low reflectance is mounted is compensated for by increasing the gain of the driver, and the increase in the gain of the servo DSP is suppressed.
[0020]
FIG. 1A is a diagram schematically showing a servo system (focus servo system) of the optical disc reproducing apparatus according to the first embodiment. However, the actuator coil in the figure is a focusing actuator that adjusts a focal position and focuses a laser beam.
[0021]
In this device, at least data of a signal amplitude value of a focus error signal output from a head amplifier (signal amplifier) when a laser beam is focused in a state of an initial gain set in advance using CDDA as a reference disk. However, a storage area for storing table data described for each optical disk having a different reflectance, such as CDDA, CD-R, and CD-RW, is provided in a microcontroller (not shown) or the like. The function of measuring the amplitude value of the error signal is provided in a servo DSP (focus feedback amplification adjuster) or the like, and the measurement result is compared with a data table to determine the type of the optical disk, and the CD-R, CD-RW The amplitude value of the drive signal output from the servo DSP in the initial gain setting And a function of adjusting the gain of the driver to match those of the case (focus driver) (gain adjusting means) to have the microcontroller or the like.
[0022]
Specifically, as shown in FIG. 1 (a), a resistor element group configured so that the input impedance of the driver switches to an appropriate value in accordance with the type of the optical disk is provided, and the data table includes a CDDA when the CDDA is mounted. The data of the switching multiple based on the amplitude value of the focus error signal (the amplitude value of the drive signal) is also described, and the type of the optical disc is determined using this data table, and the input impedance of the driver is switched. I have. The resistance element group may be provided inside the driver, or may be provided outside.
[0023]
Hereinafter, the phase compensation gain adjustment in the device will be described. First, before performing the phase compensation gain adjustment by the servo DSP, the laser beam is focused by performing a focus search operation or the like in the initial gain setting for the CDDA. Then, in this state, a focus error signal from the head amplifier is obtained, an analog / digital conversion is performed by the servo DSP to measure an amplitude value, and the measured result is compared with a data table prepared in advance to mount the optical disc 1 mounted thereon. Is determined. The data described in the data table is data obtained in the initial gain setting for CDDA before the phase compensation gain adjustment.
[0024]
As a result of the discrimination, if the disc is a CD-R, the input resistance value of the driver is switched to 1/2 of the value with respect to the CDDA, and the gain of the driver is increased twice as much as when the CDDA is mounted. In the case of a CD-RW, the input resistance value of the driver is switched to の of the value with respect to the CDDA, and the gain of the driver is increased to four times that when the CDDA is mounted.
[0025]
Next, normal phase compensation gain adjustment is performed. That is, the focus servo is turned on, a disturbance of 750 Hz is injected into the focus servo loop, and the gain of the servo DSP is adjusted so that the open loop gain of the focus servo becomes 0 dB.
[0026]
As described above, since the gain of the focus servo system when the optical disk with low reflectance is mounted is adjusted by adjusting the gain of the driver, it is possible to suppress an increase in the gain of the servo DSP at the time of adjusting the phase compensation gain. Defocus of the focus servo due to the cross signal can be prevented.
[0027]
(Embodiment 2)
In the optical disk reproducing apparatus according to the second embodiment, by changing the laser power amount according to the type of the mounted optical disk, the gain of the servo DSP in the phase compensation gain adjustment at the time of mounting the optical disk with low reflectance is adjusted. Try to suppress the rise. In other words, the lack of gain of the focus servo system when the optical disk having a low reflectance is mounted is compensated for by increasing the amount of laser power, thereby suppressing an increase in the gain of the servo DSP.
[0028]
FIG. 1B is a diagram schematically showing a servo system (focus servo system) of the optical disc reproducing apparatus according to the second embodiment. However, the laser driver in the figure is a driver for driving a laser diode in the optical pickup.
[0029]
In this device, at least data of a signal amplitude value of a focus error signal output from a head amplifier (signal amplifier) when a laser beam is focused in a state of an initial gain set in advance using CDDA as a reference disk. However, a storage area for storing table data described for each optical disk having a different reflectance, such as CDDA, CD-R, and CD-RW, is provided in a microcontroller (not shown) or the like. The function of measuring the amplitude value of the error signal is provided in a servo DSP (focus feedback amplification adjuster) or the like, and the measurement result is compared with a data table to determine the type of the optical disk. The amplitude value of the focus error signal output from the head amplifier in the initial gain setting state when the RW is mounted , And functions to adjust the laser power of emitted laser light of the optical pickup by switching the gain of the laser driver (laser power adjusting means) to have the microcontroller or the like so as to match those of CDDA is installed.
[0030]
Specifically, a laser driver that drives a laser source that generates laser light is provided with a resistance element group configured so that the value of the current output to the laser source switches to an appropriate value according to the type of the optical disk. In the data table, data of the switching multiple based on the amplitude value of the focus error signal when the CDDA is mounted is also described, and the type of the optical disk is determined using the data table, and the current value output by the laser driver is determined. I'm trying to switch.
[0031]
Hereinafter, the phase compensation gain adjustment in the device will be described. First, before performing the phase compensation gain adjustment by the servo DSP, the laser beam is focused by performing a focus search operation or the like in the initial gain setting for the CDDA. Then, in this state, a focus error signal from the head amplifier is obtained, analog / digital conversion is performed by a servo DSP to measure the amplitude value, and the measurement result is compared with a data table prepared in advance to compare the data table with a data table prepared in advance. Determine the type. The data described in the data table is data obtained in the initial gain setting for CDDA before the phase compensation gain adjustment.
[0032]
As a result, in the case of a CD-R, a laser driver (not shown) is controlled so that the laser power value becomes twice the value for CDDA. In the case of CD-RW, the laser driver is controlled so that the laser power value becomes four times the value for CDDA. By doing so, the amplitude value of the focus error signal from the head amplifier becomes the same for all the optical disks as when the CDDA is mounted.
[0033]
Next, normal phase compensation gain adjustment is performed. That is, the focus servo is turned on, a disturbance of 750 Hz is injected into the focus servo loop, and the gain of the servo DSP is adjusted so that the open loop gain of the focus servo becomes 0 dB.
[0034]
As described above, since the laser power amount is used to adjust the gain of the focus servo system when the optical disk having a low reflectance is mounted, it is possible to suppress an increase in the gain of the servo DSP at the time of adjusting the phase compensation gain. Defocus of the focus servo due to the cross signal can be prevented.
[0035]
【The invention's effect】
As described above, according to the present invention, even when an optical disk having a low reflectance is mounted, it is possible to satisfy the gain characteristics of the servo loop and suppress an increase in the gain of the servo DSP at the time of adjusting the phase compensation gain. Thus, it is possible to prevent the focus servo from deviating due to the track cross signal during the traverse movement.
[Brief description of the drawings]
FIG. 1A is a diagram schematically showing a servo system (focus servo system) of an optical disk reproducing device according to a first embodiment of the present invention; FIG. 1B is a diagram illustrating a servo system (focus) of the optical disk reproducing device according to the first embodiment of the present invention; FIG. 2 is a diagram schematically showing a servo system in a conventional optical disc reproducing apparatus.
FIG. 3 is a diagram showing a focus servo loop for maintaining a focused state of a laser beam in a conventional optical disc reproducing device. FIG. 4 is a diagram for explaining traverse movement in the optical disc reproducing device. FIG. 6 is a diagram for explaining a phase compensation gain adjustment of a focus servo loop when a low-reflectance optical disc is mounted in a conventional optical disc reproducing apparatus. FIG. 7 is a diagram for explaining a gain characteristic of a loop filter. Figure [Explanation of symbols]
Reference Signs List 1 optical disk 2 optical pickup 3 head amplifier (signal amplifier)
4 Servo DSP (Feedback Amplifier)
5 Driver 6 Spindle motor 7 Microcontroller

Claims (4)

An optical pickup that irradiates the optical disc with laser light and converts the reflected light into a current signal;
A focus actuator for focusing a laser beam,
A signal amplifier that converts a current signal from the optical pickup into a voltage signal, amplifies the high frequency, and extracts a focus error signal;
A focus feedback amplification adjuster that sets a gain and a phase of a focus error signal from the signal amplifier and outputs a drive signal of the focus actuator;
A focus driver that drives the focus actuator with the drive signal as input, and performs phase compensation gain adjustment so that a focus servo loop system that holds a focused state of laser light satisfies predetermined gain characteristics. An optical disc reproducing apparatus for setting a gain of the focus feedback amplification adjuster,
A storage area for storing a data table in which the data of the signal amplitude value of the focus error signal obtained by focusing the laser beam with the initial gain setting for the reference disk is described for each optical disk having a different reflectance,
The data table is compared with the signal amplitude value of a focus error signal obtained by focusing the laser beam on the currently mounted optical disk with the initial gain set, and the type of the optical disk is determined. Gain adjustment means for adjusting the gain of the focus driver in accordance with the above, and adjusting the amplitude of the drive signal in the initial gain setting state to that of the reference disk. The laser beam is focused with the setting, and the gain of the focus driver is adjusted by the gain adjusting means, and then a normal phase compensation gain adjustment is performed to set the gain of the focus feedback amplifier. Optical disk playback device. An optical pickup that irradiates the optical disc with laser light and converts the reflected light into a current signal;
A focus actuator for focusing a laser beam,
A signal amplifier that converts a current signal from the optical pickup into a voltage signal, amplifies the high frequency, and extracts a focus error signal;
A focus feedback amplification adjuster that sets a gain and a phase of a focus error signal from the signal amplifier and outputs a drive signal of the focus actuator;
A focus driver that drives the focus actuator with the drive signal as input, and performs phase compensation gain adjustment so that a focus servo loop system that holds a focused state of laser light satisfies predetermined gain characteristics. An optical disc reproducing apparatus for setting a gain of the focus feedback amplification adjuster,
A storage area for storing a data table in which the data of the signal amplitude value of the focus error signal obtained by focusing the laser beam with the initial gain setting for the reference disk is described for each optical disk having a different reflectance,
The data table is compared with the signal amplitude value of a focus error signal obtained by focusing the laser beam on the currently mounted optical disk with the initial gain set, and the type of the optical disk is determined. Laser power adjusting means for adjusting the laser power amount of the laser light in accordance with the above, and adjusting the amplitude of the focus error signal in the initial gain setting state to that of the reference disk. An optical disc wherein the laser beam is focused while the gain is set, and the laser power amount is adjusted by the laser power adjusting means, and then a normal phase compensation gain adjustment is performed to set the gain of the focus feedback amplification adjuster. Playback device. A phase compensation gain adjustment method for an optical disc reproducing apparatus that performs phase compensation gain adjustment so that a focus servo loop system that holds a focused state of laser light satisfies predetermined gain characteristics,
The laser beam is focused on the currently loaded optical disk with the initial gain setting for the reference disk set, the signal amplitude value of the focus error signal is measured, and the measurement result is measured in advance based on the initial gain setting. The type of the optical disk is determined by comparing the stored data table of the signal amplitude value of the focus error signal for each of the optical disks having different reflectances, and the gain of the focus driver for driving the focusing actuator according to the determination result. Adjusting the amplitude of the drive signal of the focus driver in the initial gain setting state to that of the reference disk, and then performing normal phase compensation gain adjustment. . A phase compensation gain adjustment method for an optical disc reproducing apparatus that performs phase compensation gain adjustment so that a focus servo loop system that holds a focused state of laser light satisfies predetermined gain characteristics,
The laser beam is focused on the currently loaded optical disk with the initial gain setting for the reference disk set, the signal amplitude value of the focus error signal is measured, and the measurement result is measured in advance based on the initial gain setting. The type of the optical disc is determined by comparing the stored data table of the focus error signal of each optical disc having different reflectance with the stored data table, and the amount of laser power applied to the optical disc is adjusted according to the result of the determination. A phase compensation gain adjustment method for an optical disc reproducing apparatus, wherein the normal phase compensation gain adjustment is performed after the amplitude of the focus error signal in the initial gain setting state matches that of the reference disc.

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