JP2003141738A - Gain adjustment method for rf amplifier circuit in optical disk playback apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gain adjustment method for an optical disk playback apparatus by which the abnormal rotation of a spindle motor can be quickly solved by promptly detecting the abnormality of an optical disk without having a frequency generator for a spindle motor. SOLUTION: The gain adjustment method for a RF amplifier circuit in the optical disk playback apparatus comprises a first step for discriminating whether or not the amplitude of a RF signal is within predetermined threshold values (S117), and a second step for discriminating whether or not the amplitude of the RF signal is smaller than a predetermined NG level when denied in the first step (S123). When the amplitude of the RF signal is not in the predetermined threshold values and smaller than a predetermined NG level in the case where the gain of the RF amplifier circuit is successively changed to search the gain of the RF amplifier circuit at which the amplitude of the RF signal enters within the predetermined threshold values, the rotation of the spindle motor rotating the optical disk is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic adjusting method for an optical disk reproducing device, and more particularly to a gain adjusting method for an RF amplifier circuit.

[0002]

2. Description of the Related Art An outline of a conventional optical disk reproducing apparatus will be described below with reference to FIG. FIG. 3 is a block diagram showing an example of a general optical disc reproducing apparatus. Particularly, immediately after the optical disc is mounted in the optical disc reproducing apparatus,
A block diagram related to automatic adjustment performed before starting reproduction is shown, and other blocks are omitted. In the following description, an optical disc medium (not shown) is a compact disc on which music is recorded (hereinafter, also simply referred to as CD)
Will be described.

In the optical disc reproducing apparatus 20 shown in FIG. 3, an optical pickup 11 collects laser light emitted from a semiconductor laser incorporated therein and irradiates it to a target position on a disc medium to record information. Although it is to be reproduced and its structure is not shown, it is composed of an optical system and a drive mechanism system. The optical system is a mechanism for condensing laser light on the surface of the disk medium or detecting a deviation between a laser light spot and a target position on the disk medium, a semiconductor laser, lenses, a beam splitter, It is composed of a photodetector such as a photodiode (hereinafter also referred to as a photosensor) and the like.

The drive mechanism system performs focus control for causing the objective lens to follow the surface shake of the optical disk and track control for causing the track shake to follow so that the positional relationship between the target position on the disk medium and the laser light spot is constant. It is a drive mechanism (hereinafter, also referred to as an actuator) for maintaining the above, and is mainly composed of a magnet, a coil, and a support member. In addition, the drive mechanism system also includes a drive mechanism of a sled control system for moving the entire optical pickup to a target position in the radial direction of the optical disc.

In the optical pickup 11, the objective lens is connected to the focus actuator by a spring member, and the position of the objective lens (distance from the optical disk recording surface) is controlled by the focus actuator. The laser light beam passes through the objective lens and the like, is reflected by the recording surface of the optical disc medium, and enters the photodiode through a beam splitter, a condenser lens, and the like (not shown). The photodiode is, for example, a four-division photodiode, and the error signal detection means 15 detects the focus shift and the track shift using the outputs of the respective divided diodes. The error signal detecting means 15 detects the focus error signal (hereinafter, FES
A focus error signal detection circuit that detects and outputs (1) and a tracking error signal detection circuit that detects and outputs a tracking error signal (hereinafter, also referred to as TES).

The focus control system includes an optical pickup 11,
RF amplifier circuit 13, error signal detection means 15, adder circuit 17, phase compensation circuit 19, actuator drive circuit 2
1. The system is composed of the system control means 27, and the structure of the tracking control system is the same, but in the actual circuits in the two control systems, a part is common to the focus control system and the tracking control system, and a part is common. Each uses a different circuit. Regarding the focus control system, the optical disk reproducing device 20 includes an offset correction voltage generator, a focus search signal generator, a rectangular wave generator for performing focus search, a focus balance adjusting unit for performing focus balance adjustment of the focus control system, and the like. But,
Illustration is omitted.

In FIG. 3, the system control means 27 gives a focus offset correction voltage for correcting the focus offset and a tracking offset correction voltage for correcting the tracking offset to the adder circuit 17. The adder circuit 17 receives the focus error signal FE.
Each offset correction voltage is added to S and the tracking error signal TES, and the added signal is given to the phase compensation circuit 19. The phase compensation circuit 19 performs appropriate phase compensation for each system in order to improve the stability of each control loop.

The actuator drive circuit 21 makes the objective lens perpendicular to the optical disk surface so that the beam waist of the laser light emitted from the optical pickup 11 is on the recording surface of the optical disk in accordance with the output of the phase compensation circuit 19. A focus actuator drive circuit for moving,
As the beam spot illuminates the center of the track,
And a tracking actuator drive circuit for moving the objective lens in the radial direction of the optical disc. The operation of the entire optical disk reproducing device 20 is performed by the system control means 2.
Controlled by 7. Further, the system control means 27 gives the gain control signal stored in the memory to the RF amplification circuit 13, and the gain of the RF amplification circuit 13 becomes a gain according to the given gain control signal.

The RF signal processing section 30 includes an RF amplifier circuit 13,
Error signal detection means 15, reproduction RF signal generation circuit 23,
It is constituted by the RF signal amplitude detection means 25. These specific circuit blocks will be described later. Reproduction RF
The signal generation circuit 23 generates a reproduction RF signal (hereinafter, also referred to as SRF) from the output signal of the RF amplification circuit 13. The reproduction RF signal SRF is a main signal for reproducing music data and is given to a signal processing circuit (not shown) that performs EFM demodulation and the like. The RF signal amplitude detecting means 25 reproduces R
The amplitude of the F signal is detected, the amplitude values are averaged for a predetermined time, and the average value is given to the system control means 27. As will be described later, when the optical disc is mounted on the optical disc reproducing apparatus 20, automatic adjustment for making the output level of the RF amplifier circuit 13 approximately a predetermined value is performed before the optical disc is reproduced. The average value of the reproduction RF signal SRF is used.

The reason why the amplitude of the reproduced RF signal SRF is not constant is that the emission intensity of the laser diode of the optical pickup 11, the reflectance of the optical disc, and the sensitivity of the photodetector vary or change. And playback RF
When the amplitude of the signal SRF is abnormal, the error signal detecting means 15 cannot obtain an error signal having a sufficient amplitude, or the jitter of the signal obtained by the discrimination circuit is large, or the error rate of the demodulated signal is high. Problems are likely to occur.

On the other hand, the causes of focus offset and focus imbalance are, for example, that the angle between the optical disk surface and the optical pickup 11 is incorrect, the difference in sensitivity of each diode in the four-division photodiode, and the offset voltage of the electric circuit. and so on. When the focus control system has an offset signal,
This means that accurate focus control cannot be performed, and if the focus balance is poorly adjusted, focus pull-in may be impossible. The same applies to the tracking control system, and when the DC offset of the tracking system is large or the balance adjustment is bad, the residual error of tracking becomes large, and it takes a long time to pull in or the track is easily deviated.

Therefore, when an optical disk to be reproduced is mounted on the optical disk reproducing apparatus 20 in order to perform accurate focus control and tracking control and to obtain reproduced data with a low error rate, the optical disk is first reproduced before reproduction. The playback device is automatically adjusted. As part of this automatic adjustment, the gain adjustment of the RF amplifier circuit 13 is performed, the DC offset and balance of the focus control system and the tracking control system are corrected, and the gain adjustment of each control system is performed.

The procedure of automatic adjustment performed in a general optical disk reproducing apparatus prior to the start of reproduction will be described below. FIG. 4 is a flowchart showing an example of an automatic adjustment procedure for a general optical disc reproducing apparatus. Figure 4
When the optical disc is loaded in the optical disc reproducing device 20, the optical pickup 11 is placed in the innermost peripheral portion, offset correction of the tracking control system is performed in step S11, and the process proceeds to step S13. Step S13
Then, start the laser light source of the optical pickup 11 (ON)
Then, the process proceeds to step S15. In step S15, offset correction of the focus control system is performed, and the process proceeds to step S17. In step S17, focus search is performed and the loop of the focus control system is closed (focus servo ON).
And proceeds to step S19.

In step S19, the loop of the spindle control system for rotating the turntable at a predetermined speed is closed (spindle servo ON), and the process proceeds to step S21.
In step S21, tracking balance adjustment is performed, and the process proceeds to step S51. The tracking balance adjustment is performed by using a so-called track crossing signal generated when the laser light beam crosses the information track due to the eccentricity of the optical disk medium itself and the eccentricity due to the disk chucking. The gain of the variable gain amplifier is adjusted so that the side peak level matches.

In step S51, the loop of the tracking control system and the sled control system is closed (tracking & sled servo ON), and 600 ms is waited until the control system becomes stable, and the process proceeds to step S53. The system control means 27 controls the opening / closing of the loop of the tracking control system and the opening / closing of the loop of the sled control system. In step S53, the gain of the focus control system is adjusted, in step S55, the gain of the tracking control system is adjusted, and the process proceeds to step S57.

In step S57, the gain of the RF amplifier circuit for amplifying the output of the photodiode of the optical pickup 11 is adjusted, and the process proceeds to step S59. Step S59
Then, adjust the balance of the focus control system and perform step S
Proceed to 61. At the innermost circumference of the compact disc (CD), a TOC (table of contents) showing a list of names and recording positions of recorded music is recorded, and in step S61, the TOC area of the optical disc medium is set. A search is performed, the TOC information is read in step S63, and the process proceeds to the next processing step. In the next processing step, an operation for reading the music of the track selected by the operator with the optical pickup 11 is performed. In the adjustment of each item described above, when the adjustment value does not converge even if it is searched, the adjustment value of the item is set to the default value in most cases.

Next, an example of the gain adjustment of the RF amplifier circuit shown in step S57 of FIG. 4 will be described.
FIG. 5 is a flowchart showing a gain adjustment procedure of the RF amplifier circuit in the conventional optical disc reproducing apparatus. In the process shown in this flowchart, the gain of the RF amplifier circuit is sequentially changed to calculate the average value of the reproduction RF signal SRF,
The value of the gain of the RF amplifier circuit is searched for such that the average value is within a predetermined threshold value. In FIG. 5, in step S111, a register and a filter are set for gain adjustment of the RF amplifier circuit according to an instruction from the system control means 27, and the process proceeds to step S113. In step S113, the RF gain is set to the default value and the process proceeds to step S115. In step S115, the amplitude data of the reproduction RF signal within a predetermined time is averaged, and the process proceeds to step S117b.

In step S117b, step S115 is performed.
It is determined whether or not the average value of the amplitudes calculated in is within a predetermined threshold value. If the result is affirmative, the process proceeds to step S119, and if the result is negative, the process proceeds to step S131. In step S117b, if the average value of the amplitudes is greater than or equal to the first threshold and greater than or equal to the second threshold that is greater than the first threshold, the determination is affirmative, and otherwise the determination is negative. In step S119, it is determined whether or not the previous search with the RF gain value and the current search with the RF gain value have been carried out twice in succession from step S117b to step S119, and if affirmative, the process proceeds to step S121. If negative, the process proceeds to step S135. Step S
At 121, the current gain value of the RF amplifier circuit is stored in the RF gain memory in the system control means 27, and this flow ends.

Steps S117b to S131
In step S131, if the number of retries is greater than the specified number, the process proceeds to step S133, and if not, the process proceeds to step S135. What is the number of retries?
This is the number of times that the search is repeated by changing the value of the RF gain until the average value of the amplitudes falls within the predetermined threshold value in the negative determination in step S117b. The specified number of retries needs to be set relatively large, and is set to 32, for example. This is because the optical disc may not be abnormal even if it is determined in step S117b that the amplitude of the reproduction RF signal is too large and does not fall within the predetermined threshold, and therefore the optical disc is not mistakenly determined to be abnormal. It is necessary to take a large number of times. Therefore, in the case of an abnormal optical disk, it takes a long time to adjust the gain of the RF amplifier. In step S133, a predetermined default value is stored in the RF gain memory that stores the gain value of the RF amplifier circuit, and this flow ends.

When the process proceeds from step S131 to step S135, the number of retries is counted up, that is, incremented in step S135 and then step S137.
In step S137, the RF gain is changed from the current value by a predetermined value, and the process advances to step S115 to repeat the search for the RF gain value.

[0021]

DISCLOSURE OF THE INVENTION Optical disc reproducing apparatus 2
The focus may be normally pulled in even when the disc is turned upside down and mounted on 0 or a non-recorded disc is mounted. In such a case, if the optical disc reproducing apparatus 20 does not have a frequency generator and the rotation speed of the disc can be known only from the synchronization signal recorded on the optical disc, it means that the data is not recorded on the optical disc. The spindle motor that rotates can not be controlled, and rotation cannot be detected any more even if the spindle motor runs out of control. That is, in the RF gain adjustment in step S57 shown in FIG. 4, the abnormality in the rotation of the spindle motor cannot be detected even if the retry is repeated, and the focus balance adjustment in step S59 is performed after step S57. In addition, step S1 shown in FIG.
When the convergence value of the automatic adjustment is not obtained in the processing of 1 and later, the default value is adopted as the adjustment value for the adjustment item.

Then, after the focus balance adjustment process of step S59 shown in FIG. 4 is performed in a state where the spindle motor is running out of control, the process proceeds to the TOC search process of step S61, and this TOC search is performed within a predetermined time. When it is not possible, it is judged that the playback device is abnormal for the first time, and the process of stopping the rotation of the spindle motor is performed.
Eject the loaded optical disc. Therefore, there is a problem that the time from the start of the automatic adjustment to the ejection of the optical disk is relatively long, and the user has to wait a long time before the optical disk is ejected.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to detect abnormalities of an optical disk promptly and to abnormally rotate the spindle motor without providing a frequency generator for the spindle motor. It is an object of the present invention to provide a gain adjusting method for an optical disc reproducing apparatus that can eliminate the above problem at an early stage.

[0024]

The present invention has been made in view of the above problems, and the first invention is a gain adjusting method for an RF amplifier circuit in an optical disk reproducing apparatus,
A first step of determining whether or not the amplitude of the RF signal is within a predetermined threshold value, and if the result of the first step is negative, whether or not the amplitude of the RF signal is smaller than a predetermined NG level. And a second step of determining the gain of the RF amplification circuit by sequentially changing the gain of the RF amplification circuit to search for the gain of the RF amplification circuit within which the amplitude of the RF signal is within a predetermined threshold value. The amplitude is not within the predetermined threshold and the predetermined NG
When the level is smaller than the level, the RF adjustment in the optical disk reproducing apparatus is arranged such that the gain adjustment of the RF amplifier circuit is stopped and the rotation of the spindle motor for rotating the optical disk is stopped.
This is a method of adjusting the gain of the amplifier circuit.

According to a second aspect of the invention, in the gain adjusting method for the RF amplifier circuit in the optical disc reproducing apparatus of the first aspect, in the first step, the amplitude of the RF signal is not less than the first threshold value and not more than the second threshold value. It is a method of adjusting the gain of the RF amplifier circuit in the optical disc reproducing apparatus, wherein the NG level is set to be smaller than the first threshold value.

According to a third aspect of the invention, in the method of adjusting the gain of the RF amplifier circuit in the optical disk reproducing apparatus according to the first or second aspect, the gain of the RF amplifier circuit is sequentially changed so that the amplitude of the RF signal is within a predetermined threshold value. When searching for the gain of the RF amplifier circuit as follows, the third step of counting the number of times affirmative in the second step, that is, the number of NG times, and whether the number of NG times is greater than the predetermined number of NG times. An optical disc having a fourth step of determining whether or not the NG count is greater than a predetermined NG count, the gain adjustment of the RF amplification circuit is stopped, and the rotation of the spindle motor that rotates the optical disc is stopped. R in playback device
This is a method of adjusting the gain of the F amplifier circuit.

In a fourth aspect of the invention, in the gain adjusting method for the RF amplifier circuit in the optical disc reproducing apparatus of the third aspect, if the result of the fourth step is negative, the RF
This is a gain adjusting method for an RF amplifier circuit in an optical disc reproducing apparatus, in which the gain of the amplifier circuit is changed to search again for the gain of the RF amplifier circuit in which the amplitude of the RF signal is within a predetermined threshold value.

A fifth aspect of the present invention is the gain adjusting method of the RF amplifying circuit in the optical disc reproducing apparatus according to the first aspect or the second aspect of the invention, wherein the gain of the RF amplifying circuit is negative when the result of the second step is negative. Is sequentially changed to search the gain of the RF amplifier circuit in which the amplitude of the RF signal is within a predetermined threshold, that is, a fifth step of counting the number of retries, and whether the number of retries is greater than the predetermined number of retries. It has a sixth step of determining whether or not the gain is set to a default value of the RF amplification circuit when the result of the sixth step is affirmative, and when the result of the sixth step is negative, it is RF. R in the optical disk reproducing apparatus in which the gain of the amplifier circuit is changed to search again for the gain of the RF amplifier circuit in which the amplitude of the RF signal is within a predetermined threshold value.
This is a method of adjusting the gain of the F amplifier circuit.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. When the optical disc is mounted on the optical disc reproducing device, the control system including the optical pickup is automatically adjusted. When performing the gain adjustment of the RF amplifier circuit in this automatic adjustment, the gain of the RF amplifier circuit is sequentially changed and the RF
When searching for the gain of the RF amplifier circuit in which the amplitude of the signal is within the predetermined threshold, when the amplitude of the RF signal is not within the predetermined threshold and is smaller than the predetermined NG level, R
The gain adjustment of the F amplifier circuit is stopped, and the rotation of the spindle motor that rotates the optical disk is stopped. As a result, even in the optical disk reproducing apparatus that does not include the frequency generator for the spindle motor, it is possible to quickly detect the abnormality of the optical disk recording medium and eliminate the abnormal rotation of the spindle motor early.

Embodiments of the present invention will be described below with reference to the drawings. The block diagram of the optical disk device to which the gain adjusting method of the RF amplifier circuit of the present invention is applied is the same as the block diagram shown in FIG. Further, the overall procedure of the automatic adjustment of the optical disk reproducing apparatus according to the present invention is the same as the flowchart shown in FIG. The gain adjusting method of the RF amplifier circuit in the optical disc reproducing apparatus of the present invention described below is a process corresponding to the process of step S57 shown in FIG.

FIG. 1 is a block diagram showing a main part of an optical disk reproducing apparatus to which the present invention is applied. The four-division photodetector 40 in the optical pickup 11 and the RF signal processing part 30 are shown.
And indicates. The RF signal processing unit 30 corresponds to the RF signal processing unit 30 including the RF amplification circuit 13, the error signal detection unit 15, the reproduction RF signal generation circuit 23, and the RF signal amplitude detection unit 25 shown in FIG. In FIG. 3, the RF signal processing unit 30
Is functionally shown, and in FIG. 1, a specific configuration of the RF signal processing unit 30 is shown in a block diagram.

The four-division photodetector 40 which receives the reflected light from the optical disk is composed of four photosensors A, B, C and D such as photodiodes, and the outputs of the photosensors A and C on the diagonals thereof are added. The adder 43 adds the outputs, and the diagonal outputs of the photosensors B and D are added by the adder 41. Note that reference characters A to D indicate both of these optical sensors and their output signals. The adder circuits 45 and 51 both adder 41 and
The output signals of 43 are added to each other, and the subtraction circuit 4
Reference numerals 7 and 49 are for subtracting the output signal of the adder 41 from the output signal of the adder 43. The output signal of the adder circuit 45 is given to one input terminal of the multiplication circuit 55 via the delay circuit 53, and the output signal of the subtraction circuit 47 is given as it is to the other input terminal of the multiplication circuit 55. The output signal of the multiplication circuit 55 is given to the tracking servo system as a tracking error signal TES via an LPF (low pass filter) 57. The tracking error signal TES in this example is a tracking signal using the phase difference method.

The output signal of the subtraction circuit 49 is applied to the focus servo control system so as to be used as the focus error signal FES. Focus error signal F in this example
ES is a focus error signal by the astigmatism method.
The output signal of the adder circuit 51 is output as a sum signal (reproduced RF signal SRF) of the four-division photodetector 40 to a signal processing circuit that performs EFM demodulation and the like, and is also output to the RF signal amplitude detection means 25. The sum signal SRF serves as a main signal for reading the recorded information on the disc.

The RF signal amplitude detecting means 25 uses the reproduction RF.
The amplitude of the signal SRF is detected. For example, the upper envelope and the lower envelope are detected, and by subtracting them, the amplitude of the reproduction RF signal is detected and given to the system control means 27. The system control means 27 calculates an average value for the given amplitude value for a predetermined time, and gives a gain control signal for controlling the gain of the adding circuit 51 to the adding circuit 51 based on the average value. The adder circuit 4
5, the subtraction circuit 47, the subtraction circuit 49, and the addition circuit 51 can control their respective gains, and the gains are adjusted at the time of balance adjustment and RF gain adjustment.

The gain adjustment of the RF amplifier circuit described below is a process of setting the gain of the adder circuit 51 for generating and outputting the reproduction RF signal. FIG. 2 shows the RF in the present invention.
It is a flow chart which shows an example of the gain adjustment procedure of an amplifier circuit. In FIG. 2, the processing from step S111 to step S121 is substantially the same as that in the case of the flowchart shown in FIG. 5, and therefore the description of the same processing is omitted. In step S117, it is determined whether the average value of the amplitudes calculated in step S115 is within a predetermined threshold value. If the result is affirmative, the process proceeds to step S119, and if the result is negative, the process proceeds to step S123.

In step S123, it is determined whether or not the average value of the reproduction RF signal amplitude is smaller than a predetermined NG level. If the result is affirmative, the process proceeds to step S125, and if the result is negative, the process proceeds to step S131. In step S125,
The number of times the process proceeds from step S123 to step S125 is set as the number of NGs, and this number of NGs is incremented by 1, and the process proceeds to step S127. N in step S127
It is determined whether or not the value of the G counter is larger than 8, and if it is larger, the process proceeds to step S129, and if not, the process proceeds to step S135. The limit value of the NG counter is set to be sufficiently smaller than the specified number of retries in step S131. For example, the number of retries in step S131 is 32, and the limit value of the NG counter in step S127 is 8. Step S129
Then, the processing for forcibly stopping the spindle motor is performed, and this flow ends.

When the process proceeds from step S123 to step S131, the process proceeds to step S133 if the number of retries is greater than the specified number in step S131, and proceeds to step S135 if not. The number of retries is the number of times the search is repeated by changing the value of the RF gain until the average value of the amplitudes falls within a predetermined threshold value in the determination in step S117.

In step S133, a predetermined default value is stored as a set value in the RF gain memory that stores the gain value of the RF amplifier circuit, and this flow is ended.
When the process proceeds from step S131 to step S135, the number of retries is incremented in step S135, the process proceeds to step S137, and the RF is performed in step S137.
Step S11 after changing the gain from the current value by a predetermined value
Going to step 5, the search for the gain value of the RF amplifier circuit is repeated.

As described in detail above, according to the embodiment to which the present invention is applied, the gain of the RF amplification circuit is sequentially changed to search for the gain of the RF amplification circuit within which the amplitude of the RF signal is within a predetermined threshold value. If the amplitude of the RF signal is not within the predetermined threshold and is smaller than the predetermined NG level, the rotation of the spindle motor is stopped. When a recording optical disc is mounted, an abnormality of the optical disc can be detected promptly and the spindle motor can be stopped early. Further, the operator of the optical disk reproducing apparatus can shorten the waiting time until the abnormal optical disk is ejected, and can take out the abnormal optical disk early.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of an optical disc reproducing apparatus to which the present invention is applied.

FIG. 2 is a flowchart showing an example of a gain adjustment procedure of the RF amplifier circuit according to the present invention.

FIG. 3 is a block diagram showing an example of a general optical disc reproducing apparatus.

FIG. 4 is a flowchart showing an example of an automatic adjustment procedure for a general optical disc reproducing apparatus.

FIG. 5 is a flowchart showing a gain adjustment procedure of an RF amplifier circuit in a conventional optical disc reproducing apparatus. 5 is a flowchart showing an example of a gain adjustment procedure of the RF amplification circuit in FIG.

[Explanation of symbols] 11 Optical pickup 13 RF amplifier circuit 15 Error signal detection means 17 Adder circuit 19 Phase compensation circuit 20 Optical disc playback device 21 Actuator drive circuit 23 Playback RF signal generation circuit 25 RF signal amplitude detection means 27 System control means 30 RF signal processor 40 4-split photodetector 41,43 adder 45, 51 adder circuit 47,49 Subtraction circuit 53 Delay circuit 55 Multiplier circuit 57 LPF (low pass filter)

Claims (5)

[Claims] 1. A method of adjusting a gain of an RF amplifier circuit in an optical disk reproducing apparatus, wherein a first step of determining whether the amplitude of an RF signal is within a predetermined threshold value and a negative result of the first step. And a second step of determining whether or not the amplitude of the RF signal is smaller than a predetermined NG level, the gain of the RF amplifier circuit is sequentially changed so that the amplitude of the RF signal falls within a predetermined threshold value. When the gain of the RF amplification circuit is searched for, the amplitude of the RF signal is not within the predetermined threshold and the predetermined N
A gain adjusting method for an RF amplifier circuit in an optical disk reproducing apparatus, characterized in that when the level is lower than the G level, the gain adjustment of the RF amplifier circuit is stopped and the rotation of a spindle motor for rotating the optical disk is stopped. 2. The method of adjusting the gain of an RF amplifier circuit in an optical disk reproducing apparatus according to claim 1, wherein in the first step, the amplitude of the RF signal is equal to or more than a first threshold value and less than or equal to a second threshold value. The NG level is determined to be smaller than the first threshold value, and the gain adjustment method of the RF amplifier circuit in the optical disc reproducing apparatus is characterized by being determined. 3. A method of adjusting the gain of an RF amplifier circuit in an optical disk reproducing apparatus according to claim 1 or 2, wherein the gain of the RF amplifier circuit is sequentially changed so that the amplitude of the RF signal is within a predetermined threshold value. When searching for the gain of the circuit, a third step of counting the number of times affirmative in the second step, that is, the number of NG times, and the NG
Fourth determination of whether the number of times is greater than a predetermined number of NG times
When the NG count is greater than the predetermined NG count, the gain adjustment of the RF amplification circuit is stopped and the rotation of the spindle motor that rotates the optical disc is stopped. Circuit gain adjustment method. 4. The gain adjusting method for an RF amplifier circuit in an optical disk reproducing apparatus according to claim 3, wherein if the result of the fourth step is negative, the gain of the RF amplifier circuit is changed to change the amplitude of the RF signal. A method for adjusting the gain of an RF amplifier circuit in an optical disk reproducing apparatus, characterized in that the gain of the RF amplifier circuit within which a threshold value is within a predetermined threshold value is searched again. 5. The method for adjusting the gain of an RF amplifier circuit in an optical disk reproducing apparatus according to claim 1, wherein the gain of the RF amplifier circuit is sequentially changed when the result of the second step is negative. , A fifth step of counting the number of times of searching the gain of the RF amplifier circuit in which the amplitude of the RF signal is within a predetermined threshold, that is, the number of retries, and determining whether the number of retries is greater than the predetermined number of retries. In the sixth step, when the affirmative result is obtained in the sixth step, the gain of the RF amplifier circuit is set to a default value, and when the negative result is obtained in the sixth step, R is obtained.
A gain adjusting method for an RF amplifier circuit in an optical disc reproducing apparatus, characterized in that the gain of the F amplifier circuit is changed to search again for the gain of the RF amplifier circuit in which the amplitude of the RF signal is within a predetermined threshold value.