JP2000082225A - Optical disc player - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably move a pickup in accordance with a move of a reproducing position of a disk by comparing a signal level of a tracking position control signal of a tracking servo system with a predetermined value, and rotating a step motor by a predetermined angle according to an output signal of a control part. SOLUTION: A tracking error signal 110 is conversion-processed into a tracking control signal 112 by a tracking servo circuit 111 to drive a tracking actuator. Variation in the level of the tracking position control signal 112 is judged by a step motor control signal generation part 117, and when the variation in level exceeds a predetermined value, a signal to rotate by a predetermined angle is outputted to rotate the step motor by the angle. A pickup moving mechanism 120 moves a pickup 102 by a predetermined distance. Such a movement is repeated as an object lens 103 returns to an neutral position and a mean time value of the tracking position control signal 112 returns to a neutral position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus, and more particularly, to a pickup feed control technique in an optical disk reproducing apparatus using a stepping motor as a feed drive source of an optical pickup. .

[0002]

2. Description of the Related Art An example of an optical disc reproducing apparatus is as follows.
For example, "From CD-Audio to Personal Computer" 1990
The technique described in Corona Publishing Co., Ltd., edited by Fujio Mari and edited by Kenji Hayashi. In particular, the servo system of the optical disk is described in "3.2. Servo" of this publicly known document, pp. 40 to 56, and the high-speed data access method specific to the optical disk is described in "3.7.1. Time Information and System Control ”, pp. 86-87.

[0003] In recent years, the miniaturization of the reproducing apparatus, the speed of data reproduction and the speed of data access time have been rapidly progressing, and accordingly, the mechanism and the system control LSI have been improved.

In order to shorten the data access time, it is necessary to move the pickup at high speed and accurately. On the other hand, a high-speed and accurate movement requires a large motor, a position sensor, and the like, which conflicts with the downsizing of the reproducing apparatus.

Under such a background, a step motor that rotates at high speed and can control the rotation angle by the number of input pulses has attracted attention. Since the rotation angle of the stepping motor can be controlled by the number of input pulses, a position sensor is not required, which is suitable for downsizing the reproducing apparatus.

By the way, in reproducing an optical disk,
As described in the above-mentioned known document, when performing continuous playback, if the tracking servo system exceeds the track following range, the pickup is moved in accordance with the movement of the playback position of the disk. Need to be done.

[0007]

As described above, if a step motor is used for feeding the pickup, a position sensor is not required, which is suitable for miniaturization. However, when this step motor is used, data is continuously transmitted. Hitherto, the realization of a steady-state servo control method of a pickup feed system in which the pickup is sent while maintaining the objective lens shift within a certain range during the reproduction has not been sufficiently studied.

[0008] The present invention has been made in view of the above points,
The purpose is to keep the range in which the tracking servo system can follow the track when performing continuous data playback, and in accordance with the movement of the disk playback position,
An object of the present invention is to provide an optical disk reproducing apparatus using a step motor, which can stably move a pickup.

[0009]

In order to achieve the above-mentioned object, an optical disk reproducing apparatus according to the present invention comprises: A moving mechanism for moving the optical pickup by a predetermined distance in accordance with the rotation of the step motor by a predetermined angle, and a signal level of a tracking position control signal of a tracking servo system are compared with a predetermined value. The optical pickup is moved by a predetermined distance by rotating the step motor by a predetermined angle according to an output signal of the control unit. Further, in the present invention, the time average value of the time series value of the tracking position control signal of the tracking servo system, or the intermediate value between the maximum value and the minimum value, is compared with a predetermined value,
By generating a drive signal for rotating the stepping motor by a predetermined angle according to the comparison result, the pickup feed control of the optical disk reproducing apparatus with less malfunction is realized. Furthermore, in the present invention, the control by the optical pickup feed control system is stopped for a certain period of time, and in this state, the reproduction position is obtained by moving the reproduction position by a predetermined number of tracks by the tracking servo system. Using the signal level of the tracking position control signal of the tracking servo system, a difference between the signal level of the tracking position control signal of the tracking servo system before and after the movement is generated, and the difference value and the tracking servo system By comparing the time series value of the tracking position control signal with the time series value and generating a drive signal for rotating the stepping motor by a predetermined angle in accordance with the comparison result, it does not depend on the variation of the tracking actuator or the track pitch of the disk. Realizes pickup feed control for optical disc playback devices with less malfunction. To.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an optical disc reproducing apparatus according to the first embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes an optical disk,
2 is a pickup (optical pickup), 103 is an objective lens, 104 is a current-to-voltage conversion circuit for converting the current generated by receiving the reflected light of the disk with the photodetector, 105 is a preamplifier, 106 is a focus error signal, 107 is a focus servo circuit, 108 is a focus position control signal, 109 is a focus actuator driver, 110 is a tracking error signal, 111 is a tracking servo circuit, 112 is a track position control signal,
Reference numeral 113 denotes a track actuator driver; 114, a system controller that controls the entire apparatus; 115, control signals (servo circuit control signals) for the servo circuits 107 and 111; and 130, a low-frequency component that extracts a low-frequency component from the tracking position control signal 112. Reference numeral 116 denotes a control unit of an optical pickup feed control system, 117 denotes a step motor control signal generation unit, 118 denotes a step motor driver, 119 denotes a step motor, 120 denotes a pickup feed mechanism, and 121 denotes an optical pickup feed control. Control signal (feed control system control signal) for controlling the system control unit 116, 122 is a disk reproduction signal, 123 is a spindle motor control circuit (spindle control circuit), 124 is a spindle motor driver, 125 is a spindle motor,
Reference numeral 126 denotes an FG signal which is a signal having a frequency proportional to the number of revolutions of the spindle motor 125, 127 denotes a control signal (spindle control signal) of the spindle control circuit 123, and 128
Is a demodulation circuit for the disk reproduction signal 122, and 129 is demodulated data (demodulated data).

Here, the optical pickup feed control system according to the present invention comprises a step motor 119, a pickup feed mechanism 120, and a controller 116.

Next, the operation of this embodiment will be described. To play data from an optical disk, rotate the optical disk, focus the laser light on the signal surface of the optical disk,
The signal is reproduced by controlling the spot of the laser beam to follow the track, and the reproduced signal is demodulated to reproduce the data.

In this embodiment, the system controller 1
14 to start rotation (spindle control signal 127)
Is output to the spindle control circuit 123, and the spindle motor 125 is rotated via the spindle driver 124.

Next, a laser beam is radiated from the pickup 102 to the optical disk 101 via the objective lens 103, and the reflected light is converted into a current by the optical detector of the pickup 102. The current is then converted by the current-voltage conversion circuit 104 and the preamplifier circuit 105. , A focus error signal 106, a tracking error signal 110, and a disk reproduction signal 122, respectively.

A focus error signal 106 is converted into a focus position control signal 108 by a focus servo circuit 107.
Is converted to the focus actuator driver 1
The focus actuator is driven via 09 to move the objective lens 103 in the distance direction with respect to the optical disc 101. This constitutes a focus servo system that controls the laser beam to focus on the signal surface of the disk.

Similarly, the tracking error signal 110 is
The tracking servo circuit 111 converts the signal into a tracking position control signal 112, drives a tracking actuator via a tracking actuator driver 113, and moves the objective lens 103 in the radial direction with respect to the optical disc 101. This constitutes a tracking servo system that controls the spot of the laser beam to track the track on the disk.

The disk reproduction signal 122 is demodulated by a demodulation circuit 128, and demodulated data 129 is obtained.

Here, as data is reproduced, the laser spot moves on the disk from the inner circumference to the outer circumference of the disk along the track. Accordingly, the tracking servo system moves the objective lens from the inner circumference to the outer circumference of the disk, so that the time average value of the tracking position control signal 112 gradually increases in one direction.
In the present embodiment, the tracking position control signal 112
The level change of the step motor control signal generation unit 117
When the level change becomes larger than a predetermined value, a signal for rotating the step motor 119 by a predetermined angle is generated.

This signal is supplied to the step motor driver 11
8 is applied to the step motor 119, and the step motor 119 rotates by a predetermined angle. Step motor 119
Is rotated by a predetermined angle, the pickup feed mechanism 12
0 sends the pickup 102 a predetermined distance. As a result, the objective lens 103 returns to the vicinity of its mechanical middle point in the radial direction of the disk, so that the time average value of the tracking position control signal 112 of the tracking servo system returns to the vicinity of the predetermined center value.

By repeating the above operation,
The pickup 102 can be stably moved in accordance with the movement of the reproduction position on the disk while maintaining the range in which the tracking servo system can follow the track.

When the laser spot is moved to an arbitrary position on the optical disk 101 at a high speed, the step motor control signal generator 117 rotates the step motor 119 by a predetermined angle according to a command from the system controller 121. A signal is generated a predetermined number of times at a high speed, and the step motor 119 is rotated at a high speed by a predetermined angle. Accordingly, the pickup feeding mechanism unit 120 moves at a high speed by a predetermined distance, and can move the pickup 102 to the target position at high speed and with high accuracy.

As described above, in the present embodiment, when performing continuous reproduction, the tracking servo system keeps the range in which the track can be tracked, and stably matches the movement of the reproduction position on the disk. It is possible to provide an optical disc reproducing apparatus using a step motor that can move a pickup. In the present embodiment, the step motor control signal generator and the system controller are represented as separate components, but they can be realized as one component using a microcomputer or the like.

Next, the second embodiment of the present invention will be described with reference to FIGS.
An embodiment will be described. FIG.
FIG. 3 is a diagram schematically illustrating a state in which is mounted on the spindle motor 125 when viewed from the side, and FIG. 3 is a diagram illustrating the state in FIG. 2 viewed from above. 2 and 3, the components denoted by the same reference numerals as those in FIG. 1 indicate the same components.

In FIG. 2 and FIG.
The center of 01, 202 is the rotation center of the spindle motor 125, and r is the radius of the optical disk 101. Here, the center 201 of the optical disk 101 is shifted from the rotation center 202 of the spindle motor 125 by a distance d. This shows a case where the optical disc 101 is mounted on the spindle motor 125.

FIG. 4 shows the state shown in FIGS.
This shows a temporal change of the tracking position control signal 112 when the optical disc 101 is reproduced.

In FIG. 4, reference numeral 401 denotes an amplitude value Vd of the maximum value and the minimum value of the tracking position control signal 112, and reference numeral 402 denotes a change in a time average value of the tracking position control signal 112. Reference numeral 403 denotes a time interval between the maximum values or the minimum values of the tracking position control signal 112, which corresponds to the rotation period T of the optical disk.

As the playback position on the disk moves from the inner circumference to the outer circumference, the objective lens position moves from the inner circumference to the outer circumference. When the disc is mounted on the spindle motor as shown in FIGS.
From the perspective of each rotation, the playback track on the disc is
It moves in the inner and outer circumferences by a distance d. In order to follow the track position deviation due to this eccentricity, the tracking servo circuit 111 generates a tracking position control signal 112, drives the tracking actuator, moves the objective lens 103, and moves the track as shown in FIG. Follow the position deviation. On the other hand, since the movable range of the tracking actuator of the pickup 102 is limited, the pickup 102 is controlled so as not to exceed the movable range of the tracking actuator when following the positional deviation of the track in accordance with the movement of the reproduction position on the disk. Need to be sent from the inner circumference to the outer circumference. When the pickup 102 is stationary, the average value of the tracking position control signal 112 becomes
It changes as shown by the time average value 402 in FIG.

FIG. 5 shows a configuration of the step motor control signal generator 117 according to the present embodiment for realizing the pickup moving method of the present embodiment. In FIG. 5, components and signals having the same numbers as those in FIG. 1 indicate the same components and signals.

In FIG. 5, reference numeral 501 denotes a reference value, 502 denotes a comparator, 503 denotes a stepper motor drive waveform generator (drive waveform generator), and 504 denotes a low-pass filter 13.
It is a time average value calculation unit that generates a time average value (time average value for each predetermined time interval) of the tracking position control signal 112 that has passed 0.

The above-described tracking position control signal 112
Is reduced by the low-pass filter 130, a time average value is generated by the time average value calculation unit 504, and this is input to one input of the comparator 502.
The comparator 502 outputs, for example, a pulse when the time average value of the tracking position control signal 112 exceeds the reference value.
The drive waveform generator 503 generates a drive waveform that rotates the step motor 119 by a predetermined angle in accordance with the pulse output from the comparator 502, and this is applied to the step motor 119 via the step motor driver 118, The motor 119 rotates by a predetermined angle.

When the step motor 119 rotates by a predetermined angle, the pickup feeding mechanism 120 sends the pickup 102 by a predetermined distance. Thereby, the objective lens 10
3 returns to the vicinity of the mechanical middle point, so that the time average value of the tracking position control signal of the tracking servo system is
It returns to the vicinity of the predetermined center value.

By repeating the above operation,
The pickup can be stably moved in accordance with the movement of the reproduction position on the disk while maintaining the range in which the tracking servo system can follow the track.

In the present embodiment, the step motor control signal generator and the system controller are represented as separate components, but they can be realized as one component by using a microcomputer or the like. . In addition, the time average value calculation unit 504 of the present embodiment
Can also be used for the low-pass filter 130.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a diagram illustrating a configuration of the step motor control signal generation unit 117 according to the present embodiment.
In the figure, the components and signals having the same numbers as those in FIG.
The same components and signals are shown.

In FIG. 6, reference numeral 601 denotes a local minimum value detection unit for the output signal of the tracking position control signal 112 that has passed through the low-pass filter 130; The local maximum value detecting unit 603 is an average value calculating unit for the detected local minimum value and local maximum value.

In this embodiment, the tracking position control signal 112 is reduced by a low-pass filter 130 to reduce the fluctuation component due to eccentricity, and then the remaining minimum value and maximum value are detected by a minimum value detection unit 601 and a maximum value detection unit. At 602, each is detected. The average value (intermediate value) of the maximum value and the minimum value is calculated by the average value calculation unit 603 and input to the comparator 502. The comparator 502 outputs, for example, a pulse when the average value of the maximum value and the minimum value in the signal obtained by reducing the fluctuation component of the tracking position control signal 112 exceeds the reference value. The drive waveform generating section 503 generates a drive waveform for rotating the step motor 119 by a predetermined angle in accordance with the pulse output from the comparator 502, and this generates a drive waveform for the step motor driver 118.
Is applied to the step motor 119, and the step motor 119 rotates by a predetermined angle.

When the step motor 119 rotates by a predetermined angle, the pickup feed mechanism 120 sends the pickup 102 by a predetermined distance. Thereby, the objective lens 10
3 returns to the vicinity of the mechanical middle point, so that the time average value of the tracking position control signal of the tracking servo system returns to the vicinity of the predetermined center value.

By repeating the above operation,
The pickup can be stably moved in accordance with the movement of the reproduction position on the disk while maintaining the range in which the tracking servo system can follow the track. In the present embodiment, the average value of the local maximum value and the local minimum value of the tracking position control signal is used. However, the weighted average value of the local maximum value and the local minimum value and the displacement from the weighted average value by a predetermined value are used. The same effect can be obtained by using any value, such as the above value, which represents the average movement of the objective lens.

Further, although the step motor control signal generator and the system controller are represented as separate components, they can be realized as one component using a microcomputer or the like.

Next, the fourth embodiment of the present invention will be described with reference to FIGS.
An embodiment will be described. FIG. 7 is a diagram showing the configuration of the step motor control signal generation unit 117 according to the present embodiment. In FIG. 7, components and signals having the same numbers as those in the previous embodiment indicate the same components and signals. I have.

In FIG. 7, reference numeral 701 denotes a first sample hold unit, 702 denotes a second sample hold unit, 703 denotes a timing generation unit of the sample hold units 701 and 702,
Reference numeral 704 denotes a difference generation unit, and 705 denotes a difference value.

FIG. 8 is a diagram for explaining the operation of the present embodiment. Components having the same numbers as those in the previous embodiment indicate the same components.

In FIG. 8, reference numeral 801 denotes the objective lens 10.
3 shows a case where 3 is at position A, and 802 is
This shows the case where the objective lens 103 has moved to the position B, and 803 shows the displacement X from the position A to the position B.

FIG. 9 shows that the objective lens in FIG.
When the laser beam spot is controlled to track on the track, and when the objective lens is at position B
2 shows the tracking position control signal 112 when the laser beam spot is controlled to track on the track.

In FIG. 9, reference numeral 901 denotes an average value A between the maximum value and the minimum value of the tracking position control signal when the objective lens is at the position A, and reference numeral 902 denotes tracking when the objective lens is at the position B. The average value B of the maximum value and the minimum value of the position control signal is shown. Also, the difference value 705
Represents the difference between the average value A 901 and the average value B 902, and corresponds to the output of the difference generation unit 704 in FIG.

In the configuration shown in FIG. 7, the operation of the optical pickup feed control system is stopped, and the pickup 102 is stopped.
Is located at the position A 801 in FIG. 8, the system controller 114 sends the timing control section 703 a feed control system control signal 121 so as to generate a sample pulse to the first sample hold section 701. In response, the timing generator 703 generates a sample pulse for the first sample-and-hold unit 701, and the first sample-and-hold unit 701 samples the average value A901 in FIG. Hold this.

Next, the system controller 114 controls the tracking servo circuit 111 by the servo circuit control signal 115 to displace the objective lens 103 by a predetermined distance X and move it to a position B 802 in FIG. The moving method of the objective lens 103 can be realized by a method of continuing reproduction and waiting for the reproduction position to move, or a method of jumping a track and moving a predetermined number of tracks in a short time.

Thereafter, the system controller 114
The timing generation section 703 includes the second sample hold section 7
A feed control system control signal 121 is sent so as to generate a sample pulse with respect to 02. In response to this, the timing generation unit 703 generates a sample pulse in the second sample and hold unit 702, and the second sample and hold unit 702
The average value B902 in FIG. 9 is sampled, and is held after the end of the sample pulse.

The difference generation section 704 generates a difference value 705 between the outputs of the first sample hold section 701 and the second sample hold section 702, and this difference value 705 is
2 is input to one input terminal.

Next, after the system controller 114 moves the pickup 102 to an arbitrary position, the system controller 114 uses the servo circuit control signal 115 to
Are controlled to perform a track following operation.

As described in the third embodiment, after the tracking position control signal 112 is reduced by the low-pass filter 130 to reduce the fluctuation component due to the eccentricity, the remaining minimum value and maximum value are reduced to the minimum value. The detection is performed by the detection unit 601 and the local maximum value detection unit 602, respectively. The average value of the maximum value and the minimum value is calculated by the average value calculation unit 603,
2 is input to the other input terminal.

The comparator 502 calculates the average value of the minimum value and the maximum value in the signal obtained by reducing the fluctuation component of the tracking position control signal 112 by using the difference value 705 generated as described above.
, A pulse is output, for example. The drive waveform generator 503 generates a drive waveform that rotates the step motor 119 by a predetermined angle in accordance with the pulse output from the comparator 502, and this is applied to the step motor 119 via the step motor driver 118, Motor 1
19 rotates a predetermined angle. When the step motor 119 rotates by a predetermined angle, the pickup feeding mechanism unit 120 sends the pickup 102 by a predetermined distance. As a result, the objective lens 103 returns to the vicinity of its mechanical middle point, so that the time average value of the tracking position control signal of the tracking servo system returns to the vicinity of the predetermined center value.

By repeating the above operation,
The pickup can be stably moved in accordance with the movement of the reproduction position on the disk while maintaining the range in which the tracking servo system can follow the track. In the present embodiment, in particular, when the objective lens is separated by the predetermined distance X, the average value of the maximum value and the minimum value of the tracking position control signal is used as the reference value, so that it does not depend on the sensitivity variation of the tracking actuator. The pickup can be moved by a predetermined amount when the objective lens moves by a predetermined distance X, so that the tracking servo system can accurately maintain the range in which it can follow the track, and stabilize according to the movement of the reproduction position on the disk. The pickup can be moved to.

In the description of the present embodiment, the case where the objective lens is moved from the position A to the position B by a predetermined distance X is taken as an example, but instead of the predetermined distance X, the objective lens is moved by a predetermined number of tracks. The same effect can be obtained. Further, in the present embodiment, the average value of the local maximum value and the local minimum value is used, but the weighted average value of the local maximum value and the local minimum value,
The same effect can be obtained by using any value that represents the average movement of the objective lens, such as a value displaced by a predetermined value from the weighted average value. Further, although the step motor control signal generator and the system controller are represented as separate components, they can be realized as one component using a microcomputer or the like.

[0056]

As described above, according to the present invention, it is possible to provide an optical disk reproducing apparatus using a step motor, which can move the pickup stably in accordance with the movement of the reproducing position on the disk. There is an effect that can be. Further, in the present invention, the pickup can be moved by a predetermined amount when the objective lens moves by a predetermined distance X without depending on the sensitivity variation of the tracking actuator, so that the tracking servo system can follow the track. Thus, there is an effect that the pickup can be stably moved in accordance with the movement of the reproduction position on the disc while maintaining the accuracy of the pickup.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc reproducing device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram schematically showing a state in which an optical disk is mounted on a spindle motor when viewed from a side.

FIG. 3 is an explanatory diagram schematically showing a state corresponding to FIG. 2 when viewed from above.

FIG. 4 is an explanatory diagram showing a temporal change of a tracking position control signal.

FIG. 5 is a block diagram showing a configuration of a main part of an optical disc reproducing apparatus according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a main part of an optical disc reproducing apparatus according to a third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a main part of an optical disc reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 8 is an explanatory diagram illustrating a state transition of an objective lens for explaining an operation of a fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a tracking position control signal in the case of a position A and a position B in FIG. 8;

[Explanation of symbols]

 Reference Signs List 101 optical disk 102 pickup (optical pickup) 103 objective lens 104 current-voltage conversion circuit 105 preamplifier 106 focus error signal 107 focus servo circuit 108 focus position control signal 109 focus actuator driver 110 tracking error signal 111 tracking servo circuit 112 track position control signal 113 Tracking actuator driver 114 System controller 115 Servo circuit control signal 116 Optical pickup feed control system controller 117 Step motor control signal generator 118 Step motor driver 119 Step motor 120 Pickup feed mechanism 121 Feed control system control signal 122 Disk reproduction signal 123 Spindle control circuit 124 Spindle Data driver 125 Spindle motor 126 FG signal 127 Spindle control signal 128 Demodulation circuit 129 Demodulated data 501 Reference value 502 Comparator 503 Drive waveform generator 504 Time average value calculator 601 Minimum value detector 602 Maximum value detector 603 Average value calculator 701 First sample hold section 702 Second sample hold section 703 Timing generation section 704 Difference generation section 705 Difference value

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D117 AA02 CC01 GG01 GG03 JJ02 JJ06 5D118 AA13 BA01 BB02 BF02 CA11 CA13 CD15

Claims (4)

[Claims] An optical pickup for irradiating a signal recording surface on an optical disk with light to read information recorded on a track of the optical disk, and a light spot irradiated by the optical pickup on a signal recording surface on the optical disk. A focus servo system that focuses on the optical spot; a tracking servo system that controls the light spot to track an information recording track on the optical disc; and the optical pickup that moves as the signal reading position of the light spot moves. An optical disc reproducing apparatus having an optical pickup feed control system for causing the optical pickup feed control system to rotate at a predetermined angle in accordance with an input signal; and a predetermined angle of the step motor. A moving mechanism for moving the optical pickup by a predetermined distance in accordance with the rotation of The signal level of the tracking position control signal of the tracking servo system is compared with a predetermined value, and according to the comparison result,
A control unit for generating a drive signal for rotating the step motor by a predetermined angle, and moving the optical pickup by a predetermined distance by rotating the step motor by a predetermined angle according to an output signal of the control unit. An optical disc reproducing apparatus characterized by the above-mentioned. 2. The control unit according to claim 1, wherein the control unit compares a time average value of a time series value of a tracking position control signal of the tracking servo system with the predetermined value, and according to the comparison result, An optical disc reproducing apparatus for generating a drive signal for rotating said step motor by a predetermined angle. 3. The control unit according to claim 1, wherein the control unit compares an intermediate value between a local maximum value and a local minimum value of a time series value of the tracking position control signal of the tracking servo system with the predetermined value. An optical disc reproducing apparatus, wherein a drive signal for rotating the step motor by a predetermined angle is generated according to a result. 4. The system according to claim 1, wherein the control by the optical pickup feed control system is stopped for a predetermined time, and the reproduction position is moved by a predetermined number of tracks by the tracking servo system in this state. Using the signal levels of the tracking position control signals of the tracking servo system before and after the movement, the control unit calculates the difference between the signal levels of the tracking position control signals of the tracking servo system before and after the movement. Generating the value of the difference as the predetermined value, comparing the value of the difference with a time-series value of a tracking position control signal of the tracking servo unit, and controlling the stepping motor in accordance with the comparison result. An optical disc reproducing apparatus for generating a drive signal for rotating by a predetermined angle.