JP2002334445A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device eliminating the performance deterioration such as the increase of access time and the disabled data reproduction due to the variance of the disk by preventing too much or too little amplitude of a reproduced signal at the time right after the start of the AGC operation. SOLUTION: The device is furnished with a low range removing circuit 7 for removing the low range component with the high speed and low speed, an AGC circuit 9 for automatically amplifying a signal amplitude to the specified amplitude or amplifying with a fixed gain, an amplitude detecting circuit 13 for judging the existence of the reproduced signal, and a controller 15 for controlling the low range removing circuit 7 and the AGC circuit 9 on the basis of an output of the amplitude detecting circuit 13. During the specified time from the appearance of the reproduced signal, the response of the low range removing circuit 7 is made to the high speed and the AGC circuit 9 is made to operate with the fixed gain, then after a lapse of specified time, the response of the low range removing circuit 7 is made to the low speed, and after a lapse of certain time further from the specified time, the AGC circuit 9 is made to the AGC operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for performing reproduction or recording / reproduction, and more particularly to a field of signal processing having a function of controlling the amplitude of a reproduction signal.

[0002]

2. Description of the Related Art In recent years, the density of optical discs has been accelerated, and accordingly, in the field of signal processing, Viterbi decoding and PRML (Partial Response M / L) have been required.
Digital signal processing techniques such as aximumLikelihood) are being used. In these signal processing techniques, an A / D converter is required to convert a reproduced signal, which is an analog signal, into a multi-valued digital signal, and the information in the amplitude direction together with the information in the time axis direction of the reproduced signal is required. It is important information. That is, inputting the reproduction signal within the dynamic range of the A / D converter is a necessary condition for performing optimal digital signal processing.

In a read-only disc such as a DVD or CD in which a signal is present without interruption, the amplitude of the reproduced signal always constitutes a gain control circuit (hereinafter referred to as an AGC circuit) which automatically amplifies the amplitude to a predetermined amplitude. Thus, it can be kept almost constant. However, DVD
In the case where the unrecorded area and the recorded area are mixed and the reproduction signal is interrupted as in the RMD area of -R, since the unrecorded area exists, it is necessary to keep the AGC circuit operating at all times. Causes exhaustion. In this state, when signal reproduction of the recording area immediately after the unrecorded area is started,
Since the AGC circuit is in an improper state, it takes time to return to an appropriate amplitude of the reproduced signal, and a reproduction failure or a retry occurs, thereby deteriorating the performance of the apparatus.

In order to avoid such a state, the response of the AGC circuit is accelerated for a certain period from the start of reproduction, and a configuration having a function of quickly setting an appropriate reproduction signal amplitude is employed. Improvements have been made by, for example, adopting a configuration in which the gain of the circuit is fixed to one appropriate gain.

[0005]

However, in a configuration having a function of making the response of the AGC circuit fast for a certain period from the start of reproduction as described above, and quickly setting the amplitude of the reproduced signal to an appropriate value, the response of the AGC circuit is not increased. Needs to be slower than the band of the reproduction signal from the viewpoint of operation stability, and the amplitude of the reproduction signal immediately after the start of reproduction, that is, immediately after the start of the AGC operation is not appropriate. Further, in the configuration in which the AGC is set to a fixed gain in the reproduction standby state, there is a problem that a sag generated when the low-frequency component of the reproduction signal is removed causes a malfunction.

FIG. 7 is a block diagram showing a configuration of a conventional optical disk device. 7, 101 is an optical disk, 102 is an unrecorded area, 103 is a recorded area, 104 is an optical head, 105 is a light spot, 106 is a reproduction signal,
107 is a low-frequency elimination circuit; 108 is a low-frequency elimination reproduction signal;
09 is an AGC circuit, 110 is an AGC output signal, 111 is a binarization circuit, 112 is a binarization signal, 113 is an amplitude detection circuit, and 114 is an amplitude detection signal.

The principle of operation of the optical disk device configured as described above will be described. A reproduction signal 106 of the optical disk 101 detected by the optical head 104 becomes a low-frequency-removed reproduction signal 108 from which low-frequency components unnecessary for reproducing information by the low-frequency elimination circuit 107 have been removed, and is input to the AGC circuit 109. . When the light spot 105 is in the unrecorded area 102, the signal amplitude does not exist in the reproduction signal 106. Therefore, the amplitude detection circuit 113 determines that there is no signal amplitude, and outputs information of no signal amplitude to the amplitude detection signal 114. The AGC circuit 109 amplifies the low-frequency elimination reproduction signal 108 based on the information of the amplitude detection signal 114 having no signal amplitude, and holds the signal at a predetermined fixed gain.
The C output signal 110 is output. On the other hand, the light spot 105
Enters the recording area 103, a signal amplitude is generated in the reproduced signal 106, the amplitude detection circuit 113 determines that there is a signal amplitude, and outputs information indicating the presence of the signal amplitude to the amplitude detection signal 114. The AGC circuit 109 generates a low-frequency-removed reproduction signal 108 based on the information of the amplitude detection signal 114 having the signal amplitude.
AGC operation is performed on the signal to output an AGC output signal 110 having a signal amplitude of a predetermined amplitude.

FIG. 8 shows the behavior of each signal in FIG. The reproduction signal 106 in the case where the unrecorded area 102 and the recorded area 103 are mixed is a). Playback signal 1
06 is the amplitude detection signal 114 detected and output by the amplitude detection circuit 113. A low-frequency-removed reproduced signal 108 obtained by processing the reproduced signal 106 by the low-frequency removing circuit 107 is c). The purpose of the low-frequency removal is to remove a DC component such as a change in the reflectance of the optical disk. In order to avoid an influence on a signal, the response must be sufficiently lower than a signal band to be used. Therefore, an AC component called sag as shown in FIG. 8C is generated. The AGC circuit 109 performs an AGC operation on the unrecorded area 102 and the AGC operation on the recorded area 103 in response to the low-frequency-removed reproduced signal 108 based on the amplitude detection signal 114. Immediately after entering the recording area 103 from the unrecorded area 102, the operation is performed at a fixed gain, so that the same signal as the low-frequency-eliminated reproduction signal 108 appears in the AGC output signal 110. However, when the AGC circuit 110 switches to the AGC operation, it determines that the signal amplitude is large because the sag of the low-frequency elimination reproduction signal 108 is handled as an amplitude component, and works to reduce the gain. AG
Since the C operation is required to follow local amplitude fluctuations, its response is usually set higher than the response for low-frequency elimination. Therefore, until sag disappears from the low-frequency-eliminated reproduction signal 108,
The gain of the AGC circuit works smaller than the original gain,
The signal amplitude of the AGC output signal 110 continues to be small,
And sag remains included. When such an AGC output signal 110 is passed through the binarization circuit 111, the binarization signal 112 is not binarized at the head of the recording area at all, as shown in FIG. Even if the binarization starts, the phase shift continues until the sag disappears.

As a result, shortage of the reproduction signal immediately after the start of reproduction causes instability of PLL pull-in, data reproduction inability, or increase in access time due to retry, resulting in deterioration of reproduction performance of the apparatus. I was

The present invention has been made in view of the above-mentioned problems of the prior art, and prevents the amplitude of a reproduction signal from being excessively short or short immediately after the start of an AGC operation, increases the access time caused by the disc variation, and reproduces data. It is an object of the present invention to provide an optical disk device that can improve the performance deterioration of being impossible.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a low-frequency component removing means for removing a low-frequency component of an optical disk reproduction signal, and an automatic output signal from the low-frequency component removing means. Gain control means for amplifying the reproduction signal to a predetermined amplitude, reproduction signal detection means for judging the presence or absence of the optical disk reproduction signal, and when the reproduction signal detection means outputs no reproduction signal, the reproduction signal detection means The removal response speed of the low-frequency component removing unit is reduced or increased based on the signal without the reproduced signal to be output, and the operation of the gain control unit is held at a predetermined gain. When there is a change from the absence of the playback signal to the presence of the playback signal, the output of the playback signal detection means changes based on the timing of the change from the absence of the playback signal to the presence of the playback signal. Thus, the removal response speed of the low-frequency component removing means is increased for a predetermined time, the operation of the gain control means is held, and immediately after the predetermined time has elapsed, the removal response speed of the low-frequency component removing means is reduced. And a controller having a function of releasing the hold of the gain control means after a predetermined time has elapsed after a predetermined time has elapsed.

Further, when a storage element connected to the gain control means is provided, and when the operation of the gain control means is held, a predetermined gain value is called from the storage element and set in the gain control means. Is used to perform a hold operation.

Further, when a predetermined gain value of the storage element reproduces any one of the recording areas existing on the optical disk, the gain value of the gain control means which has been operated to release the hold is detected and stored. It is configured to perform an operation that has a value stored in the element.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disk apparatus according to the present invention includes a controller for controlling the low-frequency component removing means and the gain control means based on an output signal of the reproduction signal detecting means. Therefore, even if the recording area is entered from the unrecorded area, correct reproduction information can be obtained from the head of the recording area.

Further, by providing the storage element connected to the gain control means, different settings can be made for each of the optical disk devices and optical disks, so that the head portion of the recording area can be reproduced more correctly.

Further, when the predetermined gain value of the storage element reproduces any of the recording areas existing on the optical disk, the gain value of the gain control means which has been operated to release the hold is detected and stored. By performing the operation having the value stored in the element, once the reproducing operation is performed, the head portion of the recording area can be reproduced extremely stably thereafter.

Hereinafter, an optical disk device according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of an optical disk apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is an optical disk, 2 is an unrecorded area,
3 is a recording area, 4 is an optical head, 5 is a light spot, 6 is a reproduction signal, 7 is a low-frequency elimination circuit, 8 is a low-frequency elimination reproduction signal,
9 is an AGC circuit, 10 is an AGC output signal, 11 is a binarization circuit, 12 is a binarization signal, 13 is an amplitude detection circuit, 14 is an amplitude detection signal, 15 is a controller, 16 is a control signal A, and 17 is a control signal. Signal B.

FIG. 2 is a diagram showing a configuration of a low-frequency removing circuit of the optical disk device according to the embodiment of the present invention. In FIG. 2, 21 is a capacitor C, 22 is a resistor R1, 23 is a resistor R2, 24 is a switch A, and 25 is a reference voltage Vref.
It is one.

FIG. 3 is a diagram showing a configuration of an AGC circuit of the optical disk device according to the embodiment of the present invention. In FIG. 3, 31 is a voltage controlled amplifier, 32 is a full-wave rectifier circuit,
3 is a control voltage generation circuit, 34 is a hold voltage generation circuit V
fix, 35 is a switch B.

FIG. 4 is a diagram showing a configuration of a signal detection circuit of the optical disk device according to the embodiment of the present invention. 4, reference numeral 41 denotes a voltage clamp circuit, 42 denotes a clamp signal, 43 denotes an upper envelope detection circuit, 44 denotes an upper envelope signal, 45 denotes a comparator, and 46 denotes a reference voltage Vre.
f2 and 47 are comparison voltage settings, and 48 is a comparison voltage.

FIG. 5 shows the response and behavior of each signal in FIGS. The operation principle of the optical disk device configured as described above will be described. When the unrecorded area 2 and the recorded area 3 of the optical disc 1 are mixed,
It is assumed that the reproduced signal 6 detected by the optical head 4 is obtained as a) in FIG.

First, the amplitude of the reproduced signal 6 is detected by using the amplitude detection circuit 13. Clamp circuit 4
When the signal polarity is inverted by 1 and clamped to the reference voltage Vref2 (46 in FIG. 4), the clamp signal 42 becomes
B). When the upper envelope detection circuit 43 traces only the upward direction of the amplitude of the clamp signal 42, a waveform of c) in FIG. 5 is obtained as the upper envelope signal 44 with reference to the reference voltage Vref2. On the other hand, in the comparison voltage setting 47, the reference voltage Vre
Vref2 + ΔV obtained by adding ΔV to f2 is generated as the comparison voltage 48. Amplitude can be detected by comparing the upper envelope signal 44 with the comparison voltage 48 by a comparator 45. As the amplitude detection signal 14, an unrecorded state indicates L and a recorded state indicates H). Is obtained.

Next, based on the amplitude detection signal 14, the controller 15 outputs H when the amplitude detection signal 14 is L, and delays by Δt1 when the amplitude detection signal 14 changes from L to H. , And a control signal A (16 in FIG. 1) as shown in FIG.
Is L, and when the amplitude detection signal 14 changes from L to H, the control signal B (f in FIG. 5) changes from L to H with a delay of .DELTA.t2 from .DELTA.t1. 1
7) are generated.

When the control signal A is L, the switch A (24 in FIG. 2) is turned off, only the resistor R1 (22 in FIG. 2) is connected, and the capacitor C (21 in FIG. 2) is turned off. ) And operates at a low-frequency cutoff fc1 determined by As the low-frequency cutoff fc1, a value lower than the AGC operation band fagc is selected in advance to ensure the stability of the reproducing operation. On the other hand, when the control signal A is H, the switch A is turned on.
As a result, the resistor R1 and the resistor R2 (23 in FIG. 2) become parallel, and operate at the low-frequency cutoff fc2 determined by the capacitor C21. The resistor R2 is selected as the low-frequency cutoff fc2 such that the sag to the low-frequency elimination reproduction signal 8 disappears with time within the time Δt1. Naturally, the value is higher than the AGC operation band fagc.

The above-mentioned low-frequency elimination circuit 7 performing the above operation
However, when the reproduction signal 6 is operated based on the control signal A shown in FIG. 5E, the low-frequency-eliminated reproduction signal 8 becomes the signal shown in FIG. 5G. That is, when the signal enters the recording area from the unrecorded area and the signal amplitude appears in the reproduced signal 6, the low-frequency band removal is performed at high speed within Δt1, and the signal has no sag.

The low-frequency-removed reproduced signal 8 thus obtained
The operation of the AGC circuit 9 will now be described. As shown in FIG. 5f), when the control signal B (17 in FIG. 1) becomes L
, The switch B (3 in FIG. 3) in the AGC circuit
5) is the voltage V output from the hold voltage generation circuit 34.
5 is selected, and the signal is applied to the voltage-controlled amplifier 31. The voltage-controlled amplifier 31 has a fixed gain. When the control voltage B is L, the AG
As shown in k) of FIG. 5, a signal having a sag that disappears before the control signal A changes from H to L is output as the C output signal 10. When the full-wave rectifier circuit 32 performs full-wave rectification on the signal of the AGC output signal 10, the control signal A has a large amplitude at the beginning and the control signal A changes from H to L as shown in FIG. By this time, the signal waveform becomes stable with a value smaller than the leading value. When the control voltage generation circuit 33 operates based on this signal, the output voltage becomes a control voltage having a response as shown in i) of FIG. Here, it is assumed that the AGC operation band fagc is determined by the response of the control voltage generation circuit.

The transient response of the control voltage from the unrecorded area 2 to the recorded area 3 is provided by the low-frequency removing circuit 7 and is not present in the actual reproduced signal 6. Therefore, the voltage control amplifier 31 must not respond to this control voltage. Therefore, in order to give the control voltage to the voltage control amplifier 31 after the transient response of the control voltage is stabilized, the control signal B controlling the switch B is set at L level.
The timing of switching from H to H is adjusted. That is, from the time when the amplitude detection signal 14 changes from L to H, Δt1
+ Δt2, the control signal B is changed from L to H
, But the Δt2 is adjusted. After the control signal B becomes H, the switch B in the AGC circuit becomes the signal of j) in FIG. 5 in which the output of the control voltage generation circuit is selected, and is given to the voltage control amplifier 31. Reference numeral 31 changes the gain according to the output of the control voltage generation circuit 33. In this state, the full-wave rectifier circuit 32 and the control voltage generation circuit 33 operate following the amplitude fluctuation of the reproduction signal, and the normal AGC operation is performed.

As described above, in the optical disk device of the first embodiment, when the reproduction signal detection means outputs no reproduction signal by the controller, the reproduction signal no reproduction signal output by the reproduction signal detection means is output. Based on the signal, the removal response speed of the low-frequency component removing unit is reduced or increased, and the operation of the gain control unit is held at a predetermined gain, and the reproduction signal detection unit changes from no reproduction signal to a reproduction signal. In this case, the removal response speed of the low-frequency component removing means is increased for a predetermined time based on the timing at which the output of the playback signal detecting means changes from the absence of the playback signal to the signal having the playback signal, and The operation of the gain control means is held, and immediately after a predetermined time has elapsed or after a certain time has elapsed, the gain control means is stopped. It is intended to release the hold of the roll means. Therefore, even when entering the recording area from the unrecorded area, it is possible to shift to a smooth AGC operation, the optimum amplitude is obtained immediately after the start of reproduction, the lack of the leading portion of the recording area can be reduced as much as possible, and the PLL pull-in characteristics are excellent. ,
Correct reproduction information can be obtained.

The optical disk device according to the first embodiment shows an embodiment of the present invention, and the present invention is not limited to the above-described one and does not depart from the gist of the present invention. It goes without saying that various modifications and combinations are possible within the scope.

For example, in the optical disk device of the first embodiment, the reproduced signal is used for the amplitude detection, but the signal can be detected in the same manner or with some contrivance by using the signal after removing the low-frequency component. Further, in the optical disk device of the first embodiment, the amplitude detection circuit is used as the reproduced signal detecting means. However, any means can be applied as long as it has a function of judging the unrecorded state and the recorded state from the reproduced signal. Can be easily inferred. Further, in the optical disc device of the first embodiment,
Although the first-order high-pass filter is used as the low-frequency component removing means, any configuration may be used as long as the DC component generated in the reproduced signal can be removed and the response can be switched to a high-speed response. In addition, although the feedback type AGC circuit is used as the gain control means in the optical disc device of the first embodiment, a circuit configuration having an equivalent function may be used. For example, the effects of the present invention can be similarly obtained by using a feedforward type.

(Embodiment 2) The configuration of an optical disk device according to Embodiment 2 of the present invention is the same as that of FIG. 1, and the feature is the configuration of the AGC circuit. FIG. 6 is a diagram showing a configuration of an AGC circuit of the optical disc device according to the embodiment of the present invention. 6, the same components as those in FIG. 3 are denoted by the same reference numerals. 36 is a voltage storage means.

The second embodiment is different from the first embodiment in that the voltage V of the hold voltage generation circuit 34 in the first embodiment is different from that of the first embodiment.
While the fix is performed with a predetermined fixed value, in the second embodiment, the output voltage of the control voltage generation circuit 33 when the normal AGC operation is performed in the reproduction is stored in the voltage storage means 36, At the time of the next reproduction, the output voltage value stored in the voltage storage means 36 is called, and the hold voltage generation circuit is set so as to have the output voltage value.
An object of the present invention is to optimize a fixed gain at the start of reproduction and improve the reproduction performance at the head of a recording area.

The principle of operation of the AGC circuit according to the second embodiment of the present invention shown in FIG. 6 will be described. The basic operation is
The components are the same as those of the AGC circuit of the optical disk device according to the first embodiment, and the components having the same numbers perform the same operations. Only when the control signal B (17 in FIG. 6) is H, that is, when the AGC operation is performed with the reproduction signal,
The voltage output from the control voltage generation circuit 33 is detected and stored. Next, when the control signal B becomes L, that is, when there is no reproduction signal, the voltage storage means 36 calls up the stored information, and the output voltage of the hold voltage generation circuit 34 is used as the control voltage generation circuit 33 which was detected last time. The hold voltage generation circuit 34 is set so as to be the same as the output of (1). By such an operation, the voltage control amplifier 31 in the unrecorded area
Is always updated to the gain in the recording area,
At the beginning of the AGC output signal 10 when the data enters from the unrecorded area to the recorded area, almost the same amplitude as in the normal operation of the AGC can be obtained.

As described above, the optical disk device according to the second embodiment has the voltage storage means connected to the gain control means, and the predetermined gain value of the voltage storage means exists on the optical disk. When any of the recording areas to be reproduced is reproduced, the controller detects the gain value of the gain control means operating in hold release, stores the gain value in the voltage storage means, and stores the value stored in the voltage storage means. Is used to perform an operation of giving a fixed gain in the hold state. Therefore, if the reproduction operation is performed once, it is possible to reproduce the head portion of the recording area extremely stably without being affected by the variation of the optical disk device or the optical disk.

The optical disk device according to the second embodiment shows an embodiment of the present invention, and the present invention is not limited to the above-described one and does not depart from the gist of the present invention. It goes without saying that various modifications and combinations are possible within the scope.

[0037]

As described above, according to the optical disk apparatus of the present invention, the change in the amplitude of the equalized signal can be reduced immediately after the start of data reproduction, and the optimum amplitude can be obtained immediately after the start of reproduction. In addition, it is possible to prevent a reproduction error or the like due to an excessive or insufficient amplitude. Also, by storing the gain of the gain control means at the time of reproduction and using it as a fixed gain in the next reproduction, the above-mentioned effect is maintained or the stability is further improved without being affected by variations in devices and disks. Obtainable.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a low-frequency removing circuit of the optical disc device according to the first embodiment of the present invention;

FIG. 3 is a diagram showing a configuration of an AGC circuit of the optical disc device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an amplitude detection circuit of the optical disc device according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a response and behavior of each signal according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of an AGC circuit of the optical disc device according to the second embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional optical disk device.

FIG. 8 is a diagram showing the response and behavior of each signal according to the conventional optical disc device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 101 Optical disk 2, 102 Unrecorded area 3, 103 Recording area 4, 104 Optical head 5, 105 Light spot 6, 106 Reproduction signal 7, 107 Low-frequency elimination circuit 8, 108 Low-frequency elimination reproduction signal 9, 109 AGC circuit 10, 110 AGC output signal 11, 111 Binarization circuit 12, 112 Binarization signal 13, 113 Amplitude detection circuit 14, 114 Amplitude detection signal 15 Controller 16 Control signal A 17 Control signal B 21 Capacitor C 22 Resistance R1 23 Resistance R2 24 Switch A 25 Reference voltage Vref1 31 Voltage control amplifier 32 Full-wave rectifier circuit 33 Control voltage generation circuit 34 Hold voltage generation circuit 35 Switch B 36 Voltage storage means 41 Voltage clamp circuit 42 Clamp signal 43 Upper envelope detection circuit 44 Upper envelope signal 45 Con Correlator 46 reference voltage Vref2 47 compares voltage setting 48 compares voltage

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Kumon 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Mutsumi Iguchi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 5D044 BC03 CC04 FG04 FG05 5D090 AA01 EE17

Claims (5)

[Claims] An optical device for irradiating an optical disc with light emitted from a semiconductor laser to form a light spot, condensing and detecting a reflected light from the optical disc, and outputting a reproduction signal, to read information recorded on the optical disc. An apparatus for reproducing, a low-frequency component removing means for removing a low-frequency component of an optical disc reproduction signal, a gain control means for automatically amplifying an amplitude of an output signal of the low-frequency component removing means to a predetermined amplitude, A reproduction signal detection unit for determining the presence or absence of the optical disk reproduction signal; and a controller for controlling the low-frequency component removal unit and the gain control unit based on an output signal of the reproduction signal detection unit. When a signal is reproduced from a recording area on the optical disk in which the light spot is located in the unrecorded area, the reproduction signal is reproduced. The controller lowers or increases the removal response speed of the low-frequency component removing means based on the signal without the reproduced signal output from the signal detecting means, and holds the operation of the gain control means at a predetermined gain, When the spot enters the recording area from the unrecorded area, the controller removes the low-frequency component for a predetermined time based on the timing at which the output of the reproduction signal detection means changes from a signal without a reproduction signal to a signal with a reproduction signal. Along with increasing the removal response speed of the means,
The operation of the gain control means is held, and after a predetermined time has elapsed, the controller lowers the removal response speed of the low-frequency component removing means, and after a predetermined time has elapsed after the predetermined time has elapsed, the controller operates the gain control means. An optical disk device for releasing a hold. 2. The reproduction signal detection means outputs a signal with a reproduction signal when the amplitude of the reproduction signal is equal to or greater than a predetermined amplitude, and outputs a signal without a reproduction signal when the amplitude of the reproduction signal is less than the predetermined amplitude. The optical disk device according to claim 1, wherein 3. The response speed of the gain control means is higher than the low-speed response speed of the low-frequency component removing means, and the response speed of the gain control means is higher than the high-speed response speed of the low-frequency component removing means. 2. The optical disk device according to claim 1, wherein said optical disk device is also slow. 4. When a storage element connected to the gain control means is provided, and when the operation of the gain control means is held, a predetermined gain value is called from the storage element and set in the gain control means. 2. A hold operation is performed by using
An optical disk device as described in the above. 5. The method according to claim 1, wherein the predetermined gain value of the storage element is set such that when any of the recording areas existing on the optical disk is reproduced,
5. The optical disk device according to claim 4, wherein a gain value of the gain control means operating when the hold is released is detected and stored in the storage element.