JP2957101B2 - Optical disc player - Google Patents

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 an optical disk reproducing apparatus capable of suppressing occurrence of a reading error.

[0002]

2. Description of the Related Art Optical discs represented by compact discs (CDs) are widely used as randomly accessible audio, navigation systems or mass storage devices for computers. In order to realize random access, a jump operation for jumping over a plurality of tracks at one time is necessary. Conventionally, however, the difference between the track currently being traced by the pickup and the target track is determined and one or more jumps are performed. Had gone.

[0003]

However, the jump is performed by moving the optical disk and the pickup relatively in the radial direction of the optical disk.
If the number of tracks jumped by one jump is large, it is unavoidable that the distance from the optical axis pointing to the track currently being traced to the target track increases and the rate of occurrence of read errors increases.

[0004] In particular, a reading error frequently occurs in an optical disk having scratches or dust, and in the worst case, the access is not performed normally. The present invention has been made in view of the above problems, and an optical disc reproducing apparatus capable of suppressing the occurrence of a reading error by limiting the number of tracks jumped by one jump according to the rate of occurrence of the reading error. The purpose is to provide.

[0005]

According to a first aspect of the present invention, an optical disc reproducing apparatus moves an optical pickup in a radial direction of an optical disc within a range from one track to a predetermined upper limit track number in response to a jump command. Jumping means for jumping, error occurrence frequency measuring means for measuring error occurrence frequency per fixed time when reading data,
An upper limit track number limiting means for reducing the upper limit track number of the jump means as the error occurrence frequency measured by the error occurrence frequency measuring means increases.

An optical disc reproducing apparatus according to a second aspect of the present invention is a jumping means for causing an optical pickup to jump in a radial direction of the optical disc within a range from one track to a predetermined upper limit track number in response to a jump command. Error rate measuring means for measuring the ratio of error data to the number of data read at the time of data reading, and upper limit track number limiting means for reducing the upper limit track number of the jump means as the error rate measured by the error rate measuring means increases, Is provided.

[0007]

In the optical disk reproducing apparatus according to the first aspect of the present invention, the higher the frequency of occurrence of errors during a certain period of time, the smaller the upper limit number of tracks to be jumped by one jump.
In the optical disc reproducing apparatus according to the second invention,
The higher the error rate, which is the ratio of error data to the number of read data, the smaller the upper limit number of tracks to jump in one jump.

[0008]

FIG. 1 is a block diagram of a compact disk reproducing apparatus, which is a compact disk (hereinafter referred to as a CD) 1.
Numeral 01 is rotationally driven by a spindle motor 102. The information recorded on the CD is the optical head 103
The signal is amplified by the RF amplifier 104 and demodulated into a digital signal by the demodulator 105.

The output of the RF amplifier 104 is the RF PLL 10
The clock is also supplied to the spindle motor 107 and the clock is reproduced by the spindle motor 107 via the spindle servo 107.
2 is changed to control the linear velocity at the time of reading information constant. The output of the RF amplifier 104 is also supplied to a tracking / focus servo 108, which drives an actuator (not shown) incorporated in the optical head 103 to control tracking and focusing.

Further, the tracking signal drives a thread feed motor 110 via a slide drive circuit 109,
The optical head 103 is moved in the radial direction of the CD 10. The digital signal demodulated by the demodulator 105 performs error data detection and correction by an error detection and correction unit (hereinafter, referred to as ECC) 111, is converted into an analog signal by a D / A converter 112, and is amplified by an audio amplifier 113. Is output.

The operation of the compact disk reproducing apparatus is controlled by a control unit 12 constituted by a microcomputer.
1, jump switch 122 and jump control circuit 1
23. That is, when the jump switch 122 is turned on, the jump control circuit 123 determines the number of jump tracks and is supplied to the tracking drive circuit 108. Then, an objective lens (not shown) elastically supported in the optical head 103 and driven by an electromagnetic circuit by an output from the tracking drive circuit 108.
Further, a tracking actuator composed of a thread feed motor 110 is driven via a slide drive circuit 109 to execute a jump of a predetermined number of tracks equal to or less than the upper limit number of tracks.

The jump occurs not only when the jump switch 122 is turned on, but also due to a jump signal sent from another device. The error frequency measurement circuit 121 generates the ECC 11 generated within a predetermined time.
The number EC of error signals output every time 1 is detected and corrected is counted. The error signal number EC is sent to the jump control circuit 123, and the upper limit track number is determined according to the error signal number EC.

FIG. 2 is a graph for determining the maximum number of tracks. The horizontal axis indicates the number EC of error signals, and the vertical axis indicates the maximum number of tracks. That is, when the number EC of error signals exceeds a certain value, the upper limit track number decreases as the number EC of error signals increases. Note that, instead of the error frequency measurement circuit 121, an error rate measurement circuit that measures the ratio of the number EC of error signals to the number of read data may be used.

[0014]

According to the optical disc reproducing apparatus of the first invention, the higher the frequency of occurrence of errors during a certain period of time, the smaller the upper limit of the number of tracks that can be jumped by one jump is reduced. It is possible to prevent the tracking from becoming impossible even when reading the optical disk attached to the optical disk.

According to the optical disk reproducing apparatus of the second invention, the higher the error rate, which is the ratio of the error data to the number of read data, the smaller the upper limit number of tracks that can be jumped by one jump is reduced. It is possible to prevent the tracking from being disabled even when reading an optical disk that has been scratched or dusty.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a compact disc playback device.

FIG. 2 is a graph for determining the maximum number of tracks.

[Description of Signs] 101 ... Compact disk 102 ... Spindle motor 103 ... Optical head 104 ... RF amplifier 105 ... Demodulator 106 ... RFPLL 107 ... Spindle servo 108 ... Tracking / focus servo 109 ... Slide drive circuit 110 ... Tread feed motor 111 ... ECC 112 D / A converter 113 Audio amplifier 12 Control unit 121 Error frequency measurement circuit 122 Jump switch 123 Jump control circuit

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 7/085 G11B 21/08 G11B 21/10

Claims (2)

(57) [Claims] 1. An optical disc according to claim 1, further comprising:
In an optical disc reproducing apparatus having a jump means for jumping an optical pickup in a radial direction of an optical disc within a range of not less than a track and not more than a predetermined upper limit number of tracks, an error occurrence frequency measurement for measuring an error occurrence frequency per fixed time when reading data. An optical disc reproducing apparatus further comprising: means; and an upper limit track number limiting means for reducing an upper limit track number of the jump means as an error occurrence frequency measured by the error occurrence frequency measuring means increases. 2. The optical disk 1 according to a jump command.
An error rate for measuring the ratio of error data to the number of data read at the time of data reading in an optical disc reproducing apparatus having a jump means for jumping the optical pickup in a radial direction of the optical disc within a range of not less than a track and not more than a predetermined upper limit track number. An optical disc reproducing apparatus further comprising: a measuring unit; and an upper limit track number limiting unit that reduces an upper limit track number of the jump unit as an error rate measured by the error rate measuring unit increases.