JP2004318997A - Optical disk device and its adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set an adjustment value at which the phase deviation between a phase modulation signal and a carrier wave is dissolved in accordance with the device use conditions. <P>SOLUTION: This device has a carrier wave generating circuit 18 generating the carrier wave from the phase modulation signal generated based on the wobble on a disk, and a synchronism detecting circuit 27 comparing the phase modulation signal with the carrier wave and performing phase demodulation, speed of fixed number times of reference recording linear velocity is selected and one recording linear velocity is set from a plurality of recording linear velocity in a recording speed setting means 25, while phase compensation quantity corresponding to the recording linear velocity selected based on phase fine adjustment quantity stored in a memory 26 is outputted to a phase adjusting circuit 24, and a phase of the carrier wave is compensated based on the phase compensation quantity is compensated in the phase adjusting circuit 24 and outputted to the synchronism detecting circuit 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc apparatus to which a high-density recording optical disc such as a DVD is applied and a method of adjusting the same, and more particularly to detection and adjustment of a phase shift between a phase modulation signal and a carrier in a phase demodulation circuit.
[0002]
[Prior art]
Conventional techniques of this type are described in Patent Documents 1 to 4.
[0003]
Patent Literature 1 describes a general demodulation circuit block of DPSK (two-phase modulation signal). In particular, a carrier signal is extracted from a phase modulation signal, and the phases of the phase modulation signal and the carrier signal are compared. The technology is described.
[0004]
Patent Literature 2 describes a QPSK phase demodulation circuit including a digital circuit other than the VCO.
[0005]
Patent Document 3 describes a method of performing phase modulation on wobbles.
[0006]
Patent Document 4 discloses that, by detecting a phase difference based on a multiplication result of a phase comparison signal and a wobbling signal by a multiplier, a difference in a delay amount between a carrier wave detection system and a wobbling signal detection system such as when a frequency changes. It is described that the phase shift between the carrier and the wobbling signal can be detected even when it occurs.
[0007]
[Patent Document 1]
Japanese Patent Publication No. Hei 6-19898 [Patent Document 2]
Japanese Patent No. 2893496 [Patent Document 3]
Japanese Patent Application Laid-Open No. H10-69646 [Patent Document 4]
JP 2001-126413 A
[Problems to be solved by the invention]
In general, a recording system optical disk adopts a format in which tracks are wobbled so that the wobble signal frequency becomes constant when CLV rotation control is performed in order to accurately detect the linear velocity at each radial position in advance during manufacturing. are doing. Also, address information is required so that a recording position in an unrecorded area can be specified, and a method of forming a wobble by phase-modulating the address information as disclosed in Patent Document 3 has been considered.
[0009]
This phase modulation method can also be classified in more detail, but since the signal obtained from the optical disc is of poor quality, a two-phase modulation method (BPSK or DPSK, 0 degree and 180 degree) that can obtain a relatively high S / N can be obtained. Is the most suitable.
[0010]
As a demodulation circuit for a phase-modulated signal (wobbling signal) obtained from the phase-modulated wobble, there are an analog system shown in Patent Document 1 and a digital system shown in Patent Document 2. . These generate a carrier wave on which the phase information is superimposed by a PLL or the like based on the phase modulation signal, detect a phase difference between them (0 degree or 180 degrees in the case of BPSK), and generate the phase modulation information. Is demodulated.
[0011]
However, when a phase shift occurs between the original carrier component of the phase modulation signal and the carrier generated by the PLL, the performance of phase demodulation is reduced and erroneous detection frequently occurs. Further, these Patent Documents 1 and 2 are methods used in the field of cameras and communication, and have the following problems with optical disks.
[0012]
Only a very low signal quality can be obtained in the area of the optical disc after data recording. For this reason, after passing a phase modulation signal through a filter such as a BPF, a carrier wave required for demodulation is generated from a signal generated by a PLL or the like based on the signal. However, this filter has a configuration in which a phase change (delay) is easily generated in order to efficiently remove a phase modulation component and a noise component which are disturbances. In particular, the center frequency of the BPF varies to some extent from element to element, and this becomes a phase delay as it is, which is a factor that causes a variation in the demodulated signal from device to device.
[0013]
Also, recent optical disk devices often support a plurality of recording speeds. However, since the carrier frequency changes depending on the recording speed, there is a problem that the effect of the phase delay changes depending on the speed. Patent Document 4 proposes a method of controlling the phase of a carrier wave so as to cancel the phase change of the carrier wave. However, in the actual operation of the drive, since this control must be repeated ON / OFF due to a seek operation or the like, in order to start the phase correction control, first, the phase modulation signal is demodulated and the seek operation is performed unless the position information can be read. Does not complete. Therefore, it is necessary that a demodulated signal is always stably obtained with a fixed phase correction value.
[0014]
Accordingly, it is an object of the present invention to propose an optical disk device which sets an adjustment value for eliminating the above-mentioned phase shift in accordance with the conditions of use of the device, and which always achieves good demodulation performance, and a method of adjusting the same.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is directed to an optical disk in which a groove on a disk surface is wobbled to record position information using a two-phase modulation method. An optical disc device that records information at a position, comprising: a carrier generation unit configured to generate a carrier from a phase modulation signal generated based on the wobble; and a plurality of recording linear velocities having a constant multiple of a reference recording linear velocity. A recording speed selecting means for selecting and setting one recording linear velocity; and a phase of the carrier wave corresponding to the recording linear velocity selected by the recording speed selecting means so that the phase of the phase modulation signal and the carrier wave coincide. Setting means for setting a phase fine adjustment amount for adjusting the phase, phase adjusting means for adjusting the phase of the carrier based on the phase fine adjustment amount, and a carrier output from the phase adjusting means. Inputs the phase-modulated signal, characterized in that and a synchronous detection means for comparing the phases of the carrier and the phase-modulated signal to demodulate the phase modulated signal. With this configuration, it is possible to set an optimal amount of phase fine adjustment for each recording linear velocity supported by the optical disk device, and to stably demodulate a phase modulation signal at any recording velocity. Become.
[0016]
According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a memory means for storing a phase fine adjustment amount. With this configuration, the amount of phase fine adjustment is adjusted for each device and stored in the memory means, thereby reducing variations in demodulation performance of each device due to variations in the center frequency of the BPF and the like. Recording and playback.
[0017]
According to a third aspect of the present invention, in the invention according to the first or second aspect, the synchronous detection means has a phase difference of 90 degrees with respect to a carrier and a phase comparison signal whose phase can be finely adjusted and the phase modulation signal. A multiplying operation for detecting the output level of the multiplier while changing the phase of the phase comparison signal, and fine-adjusting the amount of change when the output level of the multiplier greatly changes. It is characterized in that it is determined as an amount. With such a configuration, a digital circuit configuration that can be relatively easily realized, in which the fine phase adjustment amount is determined based on the result of multiplication of the phase comparison signal having a phase difference of 90 degrees with the carrier and the wobbling signal. In addition, the phase difference between the phase modulation signal and the carrier can be corrected, and a stable phase demodulation signal can be obtained.
[0018]
The invention according to claim 4 is the invention according to claim 1 or 2, wherein a plurality of integration circuits for integrating output signals of the synchronous detection means at different timings, and an output value of the integration circuit is determined at predetermined time intervals. And a calculating means for obtaining an average value for the variation amount of the output values, and determining the fine phase adjustment amount according to a calculation result of the calculating means. With this configuration, it is possible to determine the phase fine adjustment amount more accurately based on the demodulation performance by obtaining the average value for the variation in the value obtained by integrating the output signal of the synchronous detection means, and to achieve stable recording. Can be played.
[0019]
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a fine phase adjustment amount of a carrier corresponding to one recording speed is set in advance, and a phase fine adjustment of the carrier at another recording speed is performed. The adjustment amount is determined by offsetting the phase fine adjustment amount by a predetermined amount during operation. With this configuration, since the phase fine adjustment amount is obtained only at a specific recording speed, the tact time in the manufacturing process can be reduced.
[0020]
According to a sixth aspect of the present invention, in a manufacturing process for manufacturing the optical disk device according to the second aspect, a value of a phase fine adjustment amount for finely adjusting a phase of a carrier wave is obtained in advance and stored in the memory means. It is characterized in that sometimes the value of the phase fine adjustment amount held in the memory is used. With this configuration, it is possible to determine the phase fine adjustment amount more accurately based on the demodulation performance by obtaining the average value for the variation in the value obtained by integrating the output signal of the synchronous detection means, and to achieve stable recording. The optical disk device can be adjusted at the time of manufacture so that the reproducing light operation is enabled.
[0021]
The invention according to claim 7 is the invention according to claim 6, wherein the synchronous detection means is provided with a phase comparison signal having a phase difference of 90 degrees with respect to the carrier and a fine adjustment of the phase. Detecting the output level of a multiplier that performs a multiplication operation with the phase comparison signal while changing the phase of the phase comparison signal, and determining the amount of change when the output level significantly changes as the carrier phase fine adjustment amount. And With such a configuration, a digital circuit configuration that can be relatively easily realized, in which the fine phase adjustment amount is determined based on the result of multiplication of the phase comparison signal having a phase difference of 90 degrees with the carrier and the wobbling signal. In addition, the phase difference between the phase modulation signal and the carrier can be corrected, and the optical disk device can be adjusted at the time of manufacture so as to obtain a stable phase demodulation signal.
[0022]
The invention according to claim 8 is the invention according to claim 6, wherein a plurality of integration circuits for integrating output signals of the synchronous detection means at different timings, and obtaining a predetermined number of output values of the integration circuits at predetermined time intervals. And a calculating means for calculating an average value for the variation amount of the output values, wherein the phase fine adjustment amount is determined according to the calculation result. With this configuration, it is possible to determine the phase fine adjustment amount more accurately based on the demodulation performance by obtaining the average value for the variation in the value obtained by integrating the output signal of the synchronous detection means, and to achieve stable recording. The optical disk device can be adjusted at the time of manufacture so that the reproducing light operation can be performed.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0024]
FIG. 1 is a schematic diagram of an apparatus according to an embodiment of the present invention.
[0025]
The light emitted from the light source 1 is condensed on a recording surface 7 on an optical disk 6 through an optical system such as a coupling lens 2, a beam splitter 3, a quarter-wave plate 4, and an objective lens 5. The light reflected on the recording surface 7 returns to the above-described optical system again, passes through the beam splitter 3, is condensed on the light receiving element 9 by the condenser lens 8, and is converted into an electric signal. Normally, the output of the light receiving element 9 is converted from a current into a voltage by the I / V amplifier 10 and various calculations are performed. However, the calculation may be performed without changing the current. Usually, the light receiving element 9 and the I / V amplifier 10 are divided into a plurality of parts, and the distance between the recording surface 7 of the optical disk 6 and the light spot focal point is determined based on each light receiving surface and the output of the I / V amplifier 10. A focus error signal, a track error signal indicating the position of a track and a light spot on the recording surface 7, an RF signal for detecting information recorded on the recording surface 7 of the optical disk 6, and the like are generated. The focus error signal and the track error signal are calculated in the servo circuit 13, and the mechanism system 14 is driven from the position data to move the light spot to the target position. The information on the recording surface 7 is calculated into an RF signal in the reproducing circuit 12 and sent to the subsequent signal processing (not shown).
[0026]
When the synchronous modulation signal is obtained by detecting the wobble, the method of detecting the wobble differs depending on the division shape of the light receiving element 9. In particular, it is assumed that the synchronous modulation signal used in the present embodiment is obtained from the reproduction signal. The simplest example is detection from a push-pull signal (one of the track error signals) obtained from the difference between the left and right light receiving element division lines along the track. The following description is based on the premise that the demodulation circuit 15 operates based on the push-pull signal output from the servo circuit 13.
[0027]
FIG. 2 is an explanatory diagram showing various signal waveforms in the demodulation circuit, and FIG. 3 is a block diagram showing a configuration of the demodulation circuit in the first embodiment. 16 is a BPF, 17 is a PLL, and 18 is a BPF 16 and a PLL 17. A carrier generation circuit for outputting a carrier; 19, an LPF; 20, a multiplier; 21, an integrator; 22, a sampling circuit; 27, an LPF 19, a multiplier 20, an integrator 21, and a sampling circuit 22; 3 shows a synchronous detection circuit that outputs demodulated information.
[0028]
First, in order to extract the phase modulation component from the phase modulation signal obtained from the wobble of the optical disk 6, it is necessary to generate a carrier wave that is not modulated at the same frequency and phase as the phase modulation signal. Therefore, first, a carrier is generated using a carrier generation circuit 18 having a band limiting filter such as a BPF 16 for removing noise and phase modulation components from the phase modulation signal and a PLL 17 for generating a stable signal. This carrier has the same frequency as the phase modulation signal and the phase is stable.
[0029]
Then, the phase of the carrier is adjusted by the phase adjustment circuit 24 and output to the multiplier 20 of the synchronous detection circuit 27.
[0030]
Further, the signal passes through the LPF 19 to remove only the noise component from the phase modulation signal, and the multiplier 20 performs a multiplication operation of the phase modulation signal and the output signal of the phase adjustment circuit 24. As a method for obtaining the phase demodulated signal from the output signal of the multiplier 20, there is a method of passing the output signal of the multiplier 20 through the low band detector 23, but in the present embodiment, the phase demodulated signal is more stably obtained. For this purpose, after the output signal of the multiplier 20 is passed through the integrator 21, the level detection is performed by the sampling circuit 22 to generate the phase demodulation information. Actually, an AGC (auto gain control) circuit or the like (not shown) is used in the preceding stage of the carrier generation circuit 18 and the synchronous detection circuit 27 in order to reduce the influence of eccentricity and imbalance of the Push-Pull signal amplitude. There are many.
[0031]
FIG. 2 shows the phase-modulated signal subjected to the phase modulation, and the waveforms of the carrier, the output signal of the multiplier 20, and the output signal of the low-frequency detector 23. As can be seen by comparing the phase modulation information with the output signal of the low band detector 23, the phase modulation information is reproduced by the level of the output signal of the low band detector 23. The basic phase demodulation operation is as described above.
[0032]
Next, the operation of the phase adjustment circuit 24 for correcting the phase shift between the carrier and the phase modulation signal will be described.
[0033]
By the way, the phase of the BPF 16 that removes a noise component and a phase modulation component included in the phase modulation signal easily changes depending on the frequency. Further, if the phase modulation signal system includes not only the LPF 19 but also the above-mentioned AGC circuit, a phase change may occur due to its influence. Further, a digital signal delay due to the PLL 17 or the like may occur. Therefore, a phase difference occurs between the carrier and the phase modulation signal. If the recording linear velocity is constant, a predetermined correction value is set in the phase adjustment circuit 24, and demodulation performance can be obtained without any problem in practical use. However, when the recording linear velocity is different, the effect differs depending on the velocity, so that the optimum phase correction amount differs.
[0034]
Therefore, the optical disk device according to the present embodiment is configured so that the phase correction amount set in the phase adjustment circuit 24 for each recording speed is changed according to the operation speed of the device. The recording speed of an optical disk is generally represented by a multiple of the reference speed, such as 2 × or 4 ×. However, the optimal phase fine adjustment amount that differs for each recording speed supported by these devices is stored in the nonvolatile memory 26. The phase fine adjustment amount corresponding to the recording speed set in the recording speed setting means 25 is read from the memory 26 and the phase correction amount to be output to the phase adjustment circuit 24 is set.
[0035]
Then, the phase adjustment circuit 24 adjusts the phase of the carrier based on the information signal of the phase correction amount from the recording speed setting means 25, so that a stable demodulation performance can be exhibited at any recording speed.
[0036]
Further, among these phase shift factors, especially, the center frequency f0 of the BPF 16 often has a certain variation for each component (LSI), so that an optimal phase fine adjustment amount differs for each device. I will. Therefore, the phase fine adjustment amount is adjusted for each device at the stage of manufacturing the device, and the result is recorded in the memory 26. Then, during the actual operation of the apparatus, the recording speed setting means 25 sets the amount of phase correction output to the phase adjustment circuit in accordance with the parameters recorded in the memory 26, so that a stable phase demodulation performance can be exhibited without variation for each apparatus. become.
[0037]
For example, the phase fine adjustment amount is adjusted in the manufacturing process only at a certain reference recording speed and stored in the memory 26 as a parameter, and when operating at a speed different from the adjusted speed, the phase fine adjustment amount is determined by firmware. It is also possible to set an optimal amount of phase correction by shifting by a predetermined amount.
[0038]
Then, as described above, the phase modulation signal and the carrier whose phase has been adjusted by the phase adjustment circuit 24 are input to the multiplier 20, a multiplication operation is performed, and the calculation result is input to the integrator 21. The phase state is determined by reading the output of the integrator 21 by the sampling circuit 22, and the synchronous detection and the phase demodulation information are detected. That is, as shown in FIG. 4, the level of the integrator 21 when the timing signal is output is detected, and a phase demodulation signal is generated according to the detected level. Note that although the block diagram shown in FIG. 3 has one integrator 21, a plurality of integrators may be used.
[0039]
Next, a method of obtaining an optimal phase fine adjustment amount will be described.
[0040]
First, the phase adjustment circuit 24 generates a signal having a phase different from the carrier by 90 degrees as a phase comparison signal. That is, assuming that the carrier is a SIN wave, the phase comparison signal has a relationship of a COS wave. In the case of an analog circuit, it may be easier to design the phase adjustment circuit 24 if it is included in a PLL circuit. When the phase comparison signal and the phase modulation signal passed through the LPF 19 are multiplied by the multiplier 20, a signal having a phase shift of 90 + α degrees between the two is obtained from the multiplication result. The phase shift α is the same as the phase shift between the generated carrier and the phase modulation signal.
[0041]
5 and 6 show examples of a signal having a phase shift of 90 + α degrees. FIG. 5 shows a case where there is no phase shift (α = 0), and FIG. 6 shows a case where there is a phase shift (α ≠ 0).
[0042]
From FIG. 5, when there is no phase shift, that is, since the phase difference between the phase modulated signal after passing through the LPF 19 and the phase comparison signal is 90 degrees, the output of the low-frequency detector 23 is at 0 level, and the output of the integrator 21 is near 0. To raise or lower based on a certain level. However, when there is a phase shift as shown in FIG. 6, the output of the low-frequency detector 23 changes from 0 to a certain level on the plus side (or minus side when the phase modulation signal is inverted), and the output of the integrator 21 becomes It is increasing steadily. Therefore, by detecting the output level of the low band detector 23 or the output of the integrator 21, the value of α can be calculated, and the optimum value of the fine phase adjustment amount can be obtained.
[0043]
Next, another method for obtaining an optimal phase fine adjustment amount will be described.
[0044]
In this method, the optimum value of the fine phase adjustment amount is obtained by evaluating the variation of the integrator 21. In the two-phase phase modulation method, when data is recorded on the optical disk 6, a high-frequency data component (RF component) becomes noise, so that the situation becomes more severe for wobble detection. This is the same during recording. Therefore, the point of the detection ability is how stable the phase inversion of the phase modulation signal on the optical disk can be detected even in the above-mentioned situation where there is much noise.
[0045]
Therefore, the amount of variation and the average value of the output of the integrator 21 are obtained, and the ratio is evaluated to obtain the optimum value of the fine phase adjustment amount. As shown in the integrator output of FIG. 4, the polarity of the phase demodulation signal is different between the case where the phase modulation information is 0 and the case where the phase modulation information is 1. The larger the absolute value level of the output of the integrator 21 is, the more correctly the phase modulation signal is detected. Since it is necessary to always sample signals of the same polarity for the evaluation of variation, for example, only the output of the integrator 21 of the synchronization signal is sampled a fixed number of times. The number of times of sampling is preferably as large as possible so as to be able to absorb the fluctuation due to the rotation of the disk.
[0046]
FIG. 7 is a plot of the integrator outputs of WBL # 00 and WBL # 01 corresponding to the synchronization area when WBL # 00, WBL # 01,... It is a distribution map.
[0047]
For example, in the case of a phase modulation signal such as a DVD + RW, WBL # 00, WBL # 01,..., WBL # 92 are included, and one cycle of these 93 wobbles. More specifically, the synchronization section (synchronization area in FIG. 2) has WBL # 00 to WBL # 03, the data section (data area in FIG. 2) has WBL # 04 to WBL # 07, and the constant phase area section (phase in FIG. 2). (A fixed area) are WBL # 08 to WBL # 092.
[0048]
The demodulation performance in actual operation is correctly obtained by evaluating the ratio between the average value level and the variation amount of WBL # 00 and WBL # 01 in FIG. By doing so, high demodulation performance can be obtained. The detection of the average value level and the variation amount may be obtained by a circuit or may be calculated by firmware that operates the apparatus. Alternatively, only the output of the integrator 21 and its timing signal may be output from the device to the outside, and may be obtained by an external adjustment jig.
[0049]
【The invention's effect】
According to the present invention configured as described above, the phase modulation signal can be stably demodulated at any recording speed by setting the optimal amount of phase adjustment for each recording linear velocity supported by the optical disc device. become able to.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a waveform diagram showing various signal waveforms of a demodulation circuit according to the embodiment. FIG. 3 is a block diagram showing a configuration of the demodulation circuit according to the embodiment. 4 is a waveform diagram showing the output waveform of the integrator. FIG. 5 is a waveform diagram showing the output waveform of the low-frequency detector and the output waveform of the integrator when there is no phase shift between the carrier and the phase modulation signal. FIG. 7 is a waveform diagram showing an output waveform of the low-frequency detector and an output waveform of the integrator when there is a phase shift between the phase modulation signal and the phase modulation signal. 01,..., A distribution diagram obtained by plotting the integrator outputs of WBL # 00 and WBL # 01 corresponding to the synchronization area.
DESCRIPTION OF SYMBOLS 1 Light source 2 Coupling lens 3 Beam splitter 4 1/4 wavelength plate 5 Objective lens 6 Optical disk 7 Recording surface 8 Condensing lens 9 Light receiving element 10 I / V amplifier 12 Reproduction circuit 13 Servo circuit 15 Demodulation circuit 16 BPF
17 PLL
18 Carrier wave generation circuit 19 LPF
Reference Signs List 20 Multiplier 21 Integrator 22 Sampling circuit 23 Low band detector 24 Phase adjustment circuit 25 Recording speed setting means 26 Memory 27 Synchronous detection circuit

Claims (8)

An optical disc device that records information at a desired position in an optical disc surface with respect to an optical disc that records position information using a two-phase modulation method by wobbling grooves on the disc surface,
Carrier generation means for generating a carrier from a phase modulated signal generated based on the wobble,
Recording speed selection means for selecting and setting one recording linear speed from a plurality of recording linear velocities having a relationship of a constant multiple of the reference recording linear speed;
Setting means for setting a fine phase adjustment amount for adjusting the phase of the carrier so as to match the phase of the phase modulation signal and the phase of the carrier, corresponding to the recording linear velocity selected by the recording speed selecting means;
Phase adjusting means for adjusting the phase of the carrier based on the fine phase adjustment amount,
Synchronous detection means for receiving the carrier and the phase modulation signal output from the phase adjustment means, comparing the phases of the carrier and the phase modulation signal, and demodulating the phase modulation signal,
An optical disk device comprising: 2. The optical disk device according to claim 1, further comprising a memory unit for storing the phase fine adjustment amount. The synchronous detection means includes a multiplier having a phase difference of 90 degrees with respect to a carrier and performing a multiplication operation of the phase modulation signal and a phase comparison signal whose phase can be finely adjusted, and changes a phase of the phase comparison signal. 3. The optical disk device according to claim 1, wherein the output level of the multiplier is detected while the output level of the multiplier is changed, and the amount of change when the output level of the multiplier greatly changes is determined as the amount of fine adjustment of the phase of the carrier. . A plurality of integration circuits for integrating the output signals of the synchronous detection means at different timings; a calculation means for obtaining a predetermined number of output values of the integration circuits at predetermined time intervals and obtaining an average value for the variation amount of the output values; 3. The optical disk apparatus according to claim 1, wherein the phase fine adjustment amount is determined according to a calculation result of the calculation means. A fine phase adjustment amount of a carrier corresponding to one recording speed is set in advance, and a phase fine adjustment amount of a carrier at another recording speed is determined by offsetting the phase fine adjustment amount by a predetermined amount during operation. The optical disk device according to any one of claims 1 to 4, wherein 3. A manufacturing process for manufacturing an optical disk device according to claim 2, wherein a value of a phase fine adjustment amount for finely adjusting a phase of a carrier wave is obtained in advance and stored in said memory means, and said phase fine adjustment amount held in said memory during operation. An adjustment method for an optical disk device, characterized by using a value of an adjustment amount. An output level of a multiplier provided in the synchronous detection means and performing a multiplication operation of the phase modulation signal and a phase comparison signal having a phase difference of 90 degrees with respect to a carrier and capable of finely adjusting the phase, 7. The adjustment method for an optical disk device according to claim 6, wherein the detection is performed while changing the phase of the signal, and a change amount when the output level largely changes is determined as a phase fine adjustment amount of the carrier wave. A plurality of integration circuits for integrating the output signals of the synchronous detection means at different timings; a calculation means for obtaining a predetermined number of output values of the integration circuits at predetermined time intervals and obtaining an average value for the variation amount of the output values; 7. The adjustment method for an optical disk device according to claim 6, further comprising: determining the fine phase adjustment amount according to the calculation result.

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