JPH0765507A - Disk type recording medium recording and/or reproducing apparatus - Google Patents

Abstract

PURPOSE:To control the consumption of electrical power by intermittently executing transfer to a memory from a disk at a rate faster than that of the read operation from the memory. CONSTITUTION:Data of a disk 1 is read by an optical head 3 and is once written in RAM 25 through a decoder 24. Data of RAM 25 is read at a rate slower than that of the write operation as a reproduced output. A controller 21 issues a command for operation to a servocontrol circuit 20 for controlling the optical head 3 and a spindle motor 2 on the basis of an error signal generated from an output signal of the optical head 3. Moreover, a remaining amount of data of RAM 25 is used to control the intermittent reading of the data recorded in the disk 1. During the period where data read operation from the disk 1 is being stopped, the servocontrol operation of the servocontrol circuit 20 is also stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording and / or reproducing apparatus for a disc-shaped recording medium, and more particularly to a recording and / or reproducing device for a disc-shaped recording medium which intermittently reads data from the recording medium.
Or, it relates to a reproducing device.

[0002]

2. Description of the Related Art The applicant of the present application has previously proposed a technique in which an input digital audio signal is bit-compressed and recorded in bursts with a predetermined data amount as a recording unit.

This technique uses a magneto-optical disk as a recording medium, for example, CD-I (CD-interactive).
It records and reproduces AD (adaptive difference) PCM audio data defined in an audio data format such as a CD-ROM or a digital audio data compression-coded according to another format. The compressed digital audio data has a predetermined data amount as a recording unit, for example, a sector for connection, that is, a linking sector is added to the front and rear in consideration of interleaving with data of an adjacent sector every 32 sectors, The sector is recorded intermittently.

[0006] Here, the standard so-called CD (compact disc) format (CD-DA format) data, or so-called straight PCM audio data obtained by simply linearly quantizing an analog audio signal, is approximately 1 Consider the case of bit compression to / 4 and recording / reproducing.

The reproduction time of the disc which is bit-compressed to approximately 1/4 and recorded is the straight P before compression.
This is approximately four times as large as when recording CM data, for example, data in the CD-DA format. This makes it possible to reduce the size of the device because recording / reproducing can be performed on a smaller disc for the same recording / reproducing time as a standard 12 cm CD. Further, by setting the instantaneous bit rate for recording / reproducing to be the same as that of the standard CD-DA format, the time required for actual recording / reproducing can be reduced to about 1/4. As a result, the remaining 3
The time of / 4 can be allocated to so-called retries. Specifically, at the time of recording data, there are a confirming operation for confirming whether the recording is normally performed, a so-called verify operation, and a rewriting operation when the recording is not normally performed. Further, during data reproduction, a re-read operation or the like is performed when the error rate of reproduced data is high.

Further, during reproduction, even if the mechanism servo vibrates due to disturbance or the like and the focus servo, tracking servo, etc. are deviated, the data can be surely reproduced by devising the reading of data from the disk.

In order to record / reproduce such digital audio data bit-compressed to approximately 1/4,
A buffer memory for recording and / or reproducing compressed data is required. In this memory, compressed data is continuously written at a constant rate at the time of recording, and is read out in bursts or intermittently at a speed of about 4 times. The data amount of one time at the time of this burst reading is a predetermined data amount which is the recording unit described above, for example, 32 sectors. As described above, several sectors for linking are added to the front and the rear to spatially record on the disc. , And is recorded continuously after the previous recording part.

Further, at the time of reproduction, the data amount of a predetermined recording unit, for example, 32 sectors + several sectors of linking data is reproduced from the disc in a burst or intermittent manner at a speed of about four times as described above, The linking sector is removed and written to the buffer memory. The compressed data stored continuously at a constant rate is read from this memory.

Here, when the total storage capacity of the buffer memory for recording and / or reproducing is M _T , the amount of data in which the compressed data is not written, that is, the amount of unread data and this unread data are not destroyed. The remaining storage capacity of the writable memory, that is, the sum of the writable capacity and the writable capacity is M _T. The control of writing and reading with respect to such a memory will be described below.

First, at the time of recording, the compressed data is written in the buffer memory at a constant transfer rate, and when the amount of unread data becomes a predetermined amount M _K or more, a predetermined recording unit at a transfer rate faster than the transfer rate at the time of writing. For example, it is controlled so as to read out in bursts every 32 sectors + several sectors and record on a recording medium such as a disk. Data that has not been recorded in this storage medium is retained as unread data in the memory. Here, when the recording operation on the recording medium is interrupted due to disturbance due to vibration or the like, and the recording cannot be performed normally, the amount of unread data in the memory does not decrease, and the amount of unread data is the total storage capacity of the memory. M
When it is close to _T , the unread data may be destroyed by the compressed data written at a constant rate. In consideration of this point, allow a sufficient storage capacity in the writable area of the buffer memory to prevent destruction of unread data when recording on the medium is interrupted or cannot be performed normally. It is a thing. Storage capacity of the memory (M _T -M _K), assuming the time required for restoration and re-recording or the like of the suspended state of the recording on the medium, and writes the compressed data in the memory at a constant data rate by this time period It is sufficient that the operation can be continued.

At the time of reproduction, the compressed data read in burst from the disk which is the recording medium is written in the memory and read at a constant data rate. At this time, when the amount of unread data in the memory falls below a predetermined amount M _L , it is controlled so as to read from the disk in a burst and write to the memory.

According to the above-mentioned device, even if the data reading from the disk cannot be normally performed due to disturbance or the like, the remaining unread data amount can be continuously read, and the reading operation at a constant rate is interrupted. Playback is never interrupted. This unread data amount may be set to such an extent that the operation of reading the compressed data from the memory can be continued at a constant rate for the time required to read the recorded data again on the disc, for example.

For example, a semiconductor memory has a storage capacity of 1
When an Mbit DRAM is used, the RAM becomes full of digital signals in just 0.9 seconds during music reproduction.
The digital signal that fills the DRAM corresponds to audio data for about 3 seconds when converted into an analog signal, and the digital signal can be continuously sent from the DRAM to the decompression decoder for about 3 seconds. Therefore, even if a large vibration is transmitted to the device due to disturbance,
Since the DRAM sends the digital signal to the decompression decoder for about 3 seconds, the reproduced signal is not interrupted. As described above, it is possible to reduce the size of a disc reproducing device, which is a reproducing device using a disc-shaped optical recording medium, to a portable type.

[0014]

By the way, in a small portable disc reproducing apparatus to which the above-mentioned technique is applied, a battery is used as a power source. The life of this battery (hereinafter referred to as battery life) is limited, and it is required to extend the battery life so that the battery can be used as long as possible.

A factor that shortens the battery life is wasteful power consumption in a portion of the apparatus that is not necessary for operation such as reproduction. In order to extend the battery life, it is sufficient to suppress the power consumption of circuits and the like that do not need to be operated within a range that does not affect the reproduction operation of the recording medium.

In the above-mentioned disc reproducing apparatus, the DRAM
The time required to read data from the disc is shorter than the time required to play it back using the decompression decoder, but even while the data is not being read, the optical head remains on the disc with servos such as tracking servo and focus servo applied. I am waiting at the beginning of the next data. The optical head was waiting in a so-called pose state. It is not necessary to apply servo such as tracking servo and focus servo to the optical head in the paused state, and it is not necessary to supply power to the servo circuit that performs this servo. Therefore, when the optical head is in the paused state, the electric power supplied to the servo circuit is wasted.

It is an object of the present invention to provide a disc recording and / or reproducing apparatus capable of solving the problems of the conventional apparatus as described above.

[0018]

The present invention relates to an apparatus for reproducing data recorded on a disk-shaped recording medium, which is an optical head, a servo controller, a memory and a controller. Be equipped with.

The optical head constituting the reproducing apparatus according to the present invention irradiates the disk-shaped recording medium with a light beam to read the data recorded on the recording medium. The servo control circuit performs servo control of the optical head according to the error signal generated based on the output signal from the optical head. The memory temporarily stores the data read from the optical head, and the data stored at a reading speed slower than the writing speed of the data read from the disk-shaped recording medium by the optical head is read. The controller stops the reading of the data recorded on the disk-shaped recording medium by the optical head and the first period during which the optical head reads the data recorded on the disk-shaped recording medium and writes the read data to the memory. The optical head and the memory are controlled so as to intermittently read the data recorded on the recording medium by alternately setting the second period during which only the data stored in the memory is read. The controller is the second
During the period of, the operation of the servo control unit is stopped.

Further, the present invention is a reproducing apparatus for reproducing a compressed digital audio signal recorded on a disk-shaped recording medium, which reproducing apparatus comprises an optical head, a spindle motor, a servo control section, and a decoding process. It has a unit, a memory and a controller.

The optical head constituting this reproducing apparatus irradiates the disk-shaped recording medium with a light beam to read the data recorded on this recording medium. The spindle motor rotationally drives the disk-shaped recording medium at a constant linear velocity. The servo control unit performs servo control of the optical head and the spindle motor according to the error signal generated based on the output signal from the optical head. The decoding control unit performs a decoding process on the output signal from the optical head. The memory temporarily stores the data output from the decoding control unit, and the data stored at the reading speed is read at a speed slower than the writing speed of the data output from the decoding unit. The controller stops the reading of the data recorded on the recording medium by the optical head and stores the data in the memory during the first period in which the optical head reads the data recorded on the disk-shaped recording medium and writes the read data in the memory. The optical head and the memory are controlled so as to intermittently read the data recorded on the recording medium by alternately setting the second period in which only the read of the recorded data is set. The controller stops the servo control operation of the servo control unit during the second period.

Further, the present invention is a reproducing apparatus for reproducing a compressed digital audio signal recorded on a disk-shaped recording medium, which reproducing apparatus includes an optical head, a spindle motor, an error signal generating section, and a servo. It has a control unit, a decoding processing unit, a memory, and a controller.

The optical head constituting this reproducing apparatus irradiates the disk-shaped recording medium with a light beam to read the data recorded on this recording medium. The spindle motor rotationally drives the disk-shaped recording medium at a constant linear velocity. The error signal generation unit generates a signal for generating a focusing error signal, a tracking error signal and a spindle servo signal based on the output signal from the optical head. The servo control unit generates a focus error signal based on the focus error signal output from the error signal generation unit, a tracking error signal based on the tracking error signal, and a signal for generating a spindle servo signal. To generate a spindle servo signal. The servo control unit supplies a focus servo signal and a tracking error signal to the optical head to perform focus servo and tracking servo, and also supplies a spindle servo signal to a spindle motor to perform spindle servo. The decoding processing unit performs decoding processing on the output signal from the optical head. The memory temporarily stores the data output from the decoding processing unit, and the stored data is read at a reading speed slower than the writing speed of the data output from the decoding unit. The controller reads the data recorded on the disc-shaped recording medium by the optical head and writes the read data to the memory in the first period, and stops the reading of the data recorded on the disc-shaped recording medium by the optical head to stop the memory. The optical head and the memory are controlled so as to intermittently read the data recorded on the disk-shaped recording medium by alternately setting the second period in which the data stored in the memory is read. The controller controls the servo control unit so that only the focus servo operates during the second period.

[0024]

In the reproducing apparatus according to the present invention, the first period during which the data recorded on the disk-shaped recording medium is read by the optical head and the read data is written in the memory, and the data is recorded on the disk-shaped recording medium by the optical head. The data recorded on the disk-shaped recording medium is read intermittently by alternately setting the second period in which the data reading is stopped and only the data stored in the memory is read, and during the second period, , At least stop the servo control operation.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a recording and / or reproducing apparatus for a disc-shaped recording medium according to the present invention will be described below with reference to the drawings. This embodiment shows an example in which the present invention is applied to a recording and / or reproducing apparatus using a magneto-optical disk as a disk-shaped recording medium. More specifically,
The present invention is applied to a portable recording and / or reproducing apparatus for recording and / or reproducing an audio signal on a magneto-optical disk.

The recording and / or reproducing apparatus of this embodiment has a structure as shown in FIG. 1 and uses a magneto-optical disk 1 as a recording medium. The magneto-optical disk 1 used in this device comprises a disk substrate, a recording film, and a protective film. The disk substrate that constitutes the magneto-optical disk 1 is
It is made of a material having a light transmitting property such as a synthetic resin such as polycarbonate or PMMA. Pre-grooves meandering in the radial direction of the magneto-optical disk based on address data are preliminarily formed in a spiral shape on the disk substrate. The recording film is formed of a thin film of a magneto-optical material such as TbFeCo by a method such as vapor deposition and sputtering on the surface side of the disk substrate on which the pregroove is formed. The protective film is provided on the recording film by using an ultraviolet curable resin in order to protect the recording film.

The magneto-optical disk 1 has a data recording area and a catalog area in which catalog information is recorded. Data is discretely or continuously recorded along the pre-groove in the data recording area. Recording of data in the data recording area of the magneto-optical disc 1 and reading of the recorded data are performed intermittently in units of one cluster. One cluster is composed of 32 sectors in which data is actually recorded and four linking sectors.
The first three sectors of the four linking sectors are
This is to prevent interference of CIRC interleaving applied to data between adjacent clusters. The remaining one sector following these is for sub-data.
One sector is further made up of a plurality of sound groups, and 11 sound groups make up a pair of two sectors. In this example, one sector has 2352 bytes, and of these, there is 2332 bytes for data. One sound group is 424 bytes. Also,
One sound group corresponds to 512 samples of audio signals for the right channel and the left channel, and a reproduction time of 11.61 msec. In the inventory area,
Title information on the data or program recorded in the data area, address information such as the start address and end address of each data or program, and information indicating the connection relationship of the parts P as each small record are recorded. This catalog area is read by the optical pickup described later after the magneto-optical disk 1 is loaded in the recording and / or reproducing apparatus and before the data recording or data reproducing operation to the data recording area, and the catalog area is read. The data is stored in a recording area in a system controller described later or in a recording area in a dedicated system controller provided in a buffer memory described later. The start address and end address recorded in the inventory area are each composed of 24-bit data. The upper 14 bits are the cluster number, the next 6 bits are the sector number, and the lower 4 bits are the sound group number. ing. Correspondingly, the optical disk 1 meanders in the radial direction of the disk based on the signal modulated based on the address data including the addresses of the pre-groove cluster and the sector. By demodulating the signal obtained by reading the pregroove, the system controller, which will be described later, confirms and manages the recording position or the reproducing position during the recording or reproducing operation.

The magneto-optical disc 1 is housed in a disc cartridge (not shown). In a disc cartridge (not shown), a pair of openings are formed at positions on the upper and lower surfaces of the disc cartridge body which face each other. A recording or reproducing operation is performed on the accommodated magneto-optical disk 2 through these openings. A shutter that opens and closes a pair of openings is movably attached to the disc cartridge body in the disc cartridge. The shutter is moved in a direction to open the pair of openings by loading the disc cartridge into the recording and / or reproducing apparatus, and the shutter opens when the disc cartridge is ejected from the recording and / or reproducing apparatus. Moved in the direction of opening.

The magneto-optical disk 1 comprises a spindle motor 2
The rotating operation is performed so that the linear velocity becomes constant. A turntable (not shown) is provided on the tip end side of the rotation shaft of the spindle motor 2 for rotating the magneto-optical disk 1. The magneto-optical disk 1 of the disk cartridge loaded in the recording and / or reproducing apparatus is placed on the turntable.

This recording and / or reproducing apparatus comprises an optical pickup 3 having an objective lens which constitutes means for recording and / or reproducing an audio signal on the magneto-optical disk 1.
The optical pickup 3 includes a laser light source, an optical system such as a beam splitter for separating a light beam emitted from the light source and a return light beam from the magneto-optical disk 1, and a light detector for receiving the return light beam separated by the beam splitter. Have vessels and the like. The objective lens focuses the light beam emitted from the light source of the optical pickup 3 onto the recording film through one opening of the disc cartridge of the magneto-optical disc 1 and the disc substrate. Further, the optical pickup 3 has an actuator that drives the objective lens in the focusing direction and the tracking direction. A focusing servo signal and a tracking servo signal are supplied to this actuator from a servo control circuit described later. As a result, the objective lens is driven in the focusing direction and the tracking direction such that the focusing error signal and the tracking error signal become zero, and the focusing servo and the tracking servo are performed.

Further, there is provided a magnetic head 4 which cooperates with the optical pickup 3 and constitutes a recording means for recording an audio signal. The magnetic head 4 faces the protective film side of the magneto-optical disk 1 through the other opening of the disk cartridge. The magnetic head 4 is arranged at a position opposed to the optical pickup 3 with the magneto-optical disk 1 interposed therebetween. The magnetic head 4 generates a vertical magnetic field corresponding to recording data based on a drive signal supplied from a head drive circuit described later. The generated vertical magnetic field is applied to the recording film from the protective film side of the magneto-optical disk 1. The magnetic head 4 is mechanically connected to the optical pickup 3. When the optical pickup 3 moves in the radial direction of the magneto-optical disk 1, the magnetic head 4 also moves in the radial direction of the magneto-optical disk 1.

The optical pickup 3 is operated to be fed in the radial direction of the magneto-optical disk 1 by a feed mechanism (not shown) which uses a feed motor as a drive source.
The feed mechanism is driven by a driving force supplied based on a feed signal supplied from a servo control circuit described later.

Then, in the recording and / or reproducing apparatus shown in FIG. 1, the analog audio signal A _INL from the audio equipment is inputted through the input terminal 5. In addition, analog audio signal A from a microphone etc.
_INM is input through the input terminal 6. The analog audio signal A _INM input from the input terminal 6 is amplified by the amplifier and supplied to the selected terminal a of the switch 8. The analog audio signal A _INL from the input terminal 5 is supplied to the selected terminal b of the switch 8. The switch 8 is switched and controlled by the system control unit of the controller described later, and the analog audio signal A _INL or the analog audio signal A _INM is supplied to the low-pass filter (LPF) 9.

The LPF 9 controls the high frequency component of the input analog audio signal A _INL or analog audio signal A _INM . Automatic gain control (AGC) for analog signals whose high frequency band is limited by LPF9
The gain is adjusted by being supplied to the circuit 10. This AGC
The output signal from the circuit 10 is supplied to the selected terminal b of the switch described later and also to the A / D converter 11. The A / D converter 11 converts the analog audio signal supplied from the AGC circuit 10 into a sampling frequency 4
It is converted into a digital signal at 4.1 KHz and the digitization bit number is 16 bits.

The digital audio signal is supplied via the input terminal 12. The digital audio signal input from the input terminal 12 is supplied to the compressor described later via the digital input interface circuit 13.

Further, the recording and / or reproducing apparatus is A /
A compressor 14 to which the digital signal output from the D converter 11 and the digital signal output from the interface circuit 13 are selectively supplied is provided. Which of the digital signals output from the A / D converter 11 and the interface circuit 13 is supplied to the compressor 14 is selected by the system control unit of the controller described later. It is determined. In the compressor 14, the supplied digital audio signal is data-compressed to about 5/1. In this case, the compression technique used in compressor 14 is modified D
CT (Modified Discreat Transform) is used.

Furthermore, the buffer memory 15 in which the digital data output from the compressor 14 is temporarily stored.
And a buffer memory 25 in which digital data output by a decoder unit described later is temporarily stored. These memories 15 and 25 are controlled by a memory control unit described later. As the buffer memory 15, a DRAM having a recording capacity of 4 Mbits is used.

The digital data read from the buffer memory 15 is supplied to the EMF and CIRC encoder 16. The encoder 16 performs an encoding process for error detection and correction on the supplied digital data and a modulation process suitable for recording. In this embodiment, EMF is used.
(8-14 modulation) processing is performed. In this embodiment, the code for error detection and correction is a so-called compact disc CIR.
Interleave is changed to C (Cross Interleav Reed-Solomon Code).

The print data output from the encoder 16 is supplied to the head drive circuit 17. Head drive circuit 1
At 7, a drive signal for the magnetic head 4 is generated based on the recording data, and this drive signal is supplied to the magnetic head 4.

The output signal from the photodetector of the optical pickup 3 is supplied to the RF amplifier 18. The RF amplifier 18 generates an RF signal as a read signal of the magneto-optical disk 1 based on the output signal from the photodetector of the optical pickup 3. In the case of this embodiment, since a magneto-optical disk is used as the recording medium, R is determined based on the difference in the Kerr rotation angle of the light beam reflected by the recording film of the magneto-optical disk.
The F signal is output from the RF amplifier 18. This RF signal is supplied to the decoder described later.

Further, the RF amplifier 18 generates a focusing error signal from the output signal from the photodetector based on the so-called astigmatism method. This RF amplifier 18
A tracking killer signal is generated based on the output signal from the photodetector by the so-called three-spot method. Also, R
The F amplifier 18 generates a signal in which a meandering pre-groove is detected and a push-pull signal based on the output signal from the photodetector by the push-pull method, and supplies the push-pull signal to the address decoder. The astigmatism method is specifically described in, for example, US Pat. No. 4,023,033. The three-spot method is shown, for example, in US Pat. No. 3,909,608.

The focusing error signal and the tracking error signal generated by the RF amplifier 18 are supplied to the servo control circuit described later. The RF amplifier 18 supplies the generated RF signal to a servo control circuit described later to generate a spindle servo signal.

The push-pull signal generated by the RF amplifier 18 is supplied to the address decoder 19. The address data code 19 outputs the address data code by FM demodulating the supplied push-pull signal. The address data output from the address decoder 18 is supplied to a decoder, which will be described later, and subjected to a decoding process. The decoded address information is supplied to the system control unit of the controller, which will be described later, and is used by the system control unit, which will be described later, for confirmation of the recording position or reproduction position during recording or reproduction and position control. Address decoder 19
The sync signal extracted from the address data decoded by is supplied to a servo control circuit described later to generate a spindle servo signal.

Then, the focusing error signal and the tracking error signal generated by the RF amplifier 18 and the sync signal extracted from the RF signal or the address data are supplied to the servo control circuit 20. The servo control circuit 20 generates a focusing servo signal, a tracking servo signal, and a spindle servo signal based on these signals. The focusing servo signal and the tracking servo signal are supplied to the actuator of the optical pickup 3, and the focusing servo and the tracking servo are performed as described above. The spindle servo signal is generated based on either the RF signal or the synchronizing signal extracted from the address data. The spindle servo signal is supplied to the spindle motor 2 to control the rotation of the spindle motor 2 for rotating the magneto-optical disk 1 so that the linear velocity is constant (CLV).

Further, the servo control circuit 20 generates a feed signal. The feed signal is generated based on the low frequency component of the tracking error signal. The feed signal is supplied to a feed motor of a feed mechanism (not shown). The feed motor supplies a driving force to a feed mechanism (not shown) based on the supplied feed signal, and the optical pickup 3 and the magnetic head 4 are recorded on the magneto-optical disk 1. The track is sent in the radial direction of the magneto-optical disk 1 as the light beam of the optical pickup 3 scans. The servo control circuit 20 generates an access signal based on an access command issued from a system control unit of the controller, which will be described later, and supplies the access signal to the feed motor. In this case, an access signal is supplied to the feed motor to move the optical pickup 3 and the magnetic head 4 in the radial direction of the magneto-optical disk 1 by a feed mechanism (not shown) by a distance corresponding to the access command.

Furthermore, the recording and / or reproducing apparatus of this embodiment comprises a system controller 21. The system controller 21 is a system controller unit 2
1a and a memory control section 21b. System controller section 2 of this controller 21
An input unit 22 and a display unit 23 are connected to 1a. The system controller unit 21a starts, stops, or stops the recording or reproducing operation based on the input signal from the input unit 22.
Various control signals for performing an access operation and the like are generated, and control is performed on each unit of the recording and / or reproducing apparatus such as the servo control circuit 20, the encoder 16 and a decoder described later, and the operation of the recording and / or reproducing apparatus. Is. The output level of the light beam emitted from the optical pickup 3 is controlled by the control signal supplied from the system control unit 21a. The output level of the light beam emitted from the optical pickup 3 during the recording operation is an output level sufficient for recording, and recording is performed when the system control unit 21a recognizes that a track jump has occurred as described above. The output level is immediately lowered to an impossible output level, for example, the output level during the reproducing operation.

Further, the memory control section 21b controls writing and reading of data to the buffer memories 15 and 25, which will be described later. During the recording operation on the magneto-optical disk 1, the digital data output from the compressor 14 is written in the memory 15 by the memory control unit 21b at a transfer rate of 0.3 Mbit / sec, and the data stored in the memory is 1 It is read from the memory 15 at a transfer rate of 0.41 Mbit / sec. During the reproducing operation of the magneto-optical disk 1, the digital data output from the decoder described later is stored in the memory 25 at 1.41 Mbit / se.
The data is written at the transfer rate of c and the data stored in the memory 25 is read from the memory 25 at the transfer rate of 0.3 Mbit / sec.

The memory control section 21b compresses the recording position on the magneto-optical disk 1 if a recording position jumps to another position or another track due to a disturbance such as vibration during the recording operation. The digital data output from the device 14 is sequentially read from the memory 15 at a transfer rate that is about 5 times the data writing rate to the memory 15. The digital data read from the memory 15 is supplied to the encoder 16.

When a detection signal which detects that a track jump has occurred during the recording operation on the magneto-optical disk 1 is supplied to the system control section 21a, the memory control section 21b transfers the digital data to the encoder 16. Then, the compressed digital data from the compressor 14 is stored in the memory 15. After that, after the irradiation position of the light beam irradiated from the optical pickup 3 to the magneto-optical disk 1, that is, the recording position is corrected, the memory control unit 21b is configured to restart the transfer of digital data from the memory 15 to the encoder 16. 15
Controls writing and reading of data to and from. The recording position is corrected based on the address data of the magneto-optical disk 1.

The detection of whether or not a track jump has occurred is, for example, whether or not a vibration meter is provided in the recording and / or reproducing apparatus and the vibration detected by the vibrometer causes a track jump. Can be performed by the system control unit 21a. Further, since the address data is recorded in the pre-groove on the magneto-optical disk 1 as described above, the address data is read at the time of recording and the continuity of the decoded address data output from the address decoder described later is controlled by the system. The track jump can also be detected by monitoring the part 21a.
Furthermore, the track jump may be detected by taking the logical sum of the detection signal of the vibrometer and the signal that detects the continuity of the decoded address data. When the track jump is detected, the optical pickup 3 lowers the output level of the light beam emitted from the optical pickup 3 to the magneto-optical disk 1 to a level at which recording is not possible or sets the output level to zero.
Controlled by 1a.

In the case as described above, the buffer memory 15
As the storage capacities of 25 and 25, the storage capacity capable of storing digital data corresponding to the period from the occurrence of the track jump to the correction of the recording position to the correct position is the minimum required. In this example, as the memories 15 and 25, a DRAM having a storage capacity of 4 Mbits is used as described above,
This storage capacity satisfies the above-mentioned conditions.

Then, the memory control section 21b is
During the recording operation, during the normal recording operation, the data writing and data reading operations of the memory 15 are controlled so that the data stored in the memory 15 is reduced as much as possible. That is, when the amount of data in the memory 15 becomes equal to or larger than a predetermined amount, a predetermined amount of data, for example, data for one cluster is read from the memory 15 and a storable area having a predetermined amount or more is always stored in the memory 15. Secured.

An input section 22 is provided on the front panel of the apparatus body. The input unit 22 includes a power key for turning on / off the power of the apparatus, a reproduction key for starting a reproducing operation, a recording key for starting a recording operation, and a stop key for stopping the recording and reproducing operations. , A plurality of operation keys such as keys for performing access and the like.

A display unit 23 is provided on the front panel of the apparatus body. A display element such as a liquid crystal display or a fluorescent display tube is used for the display unit 23. The display control signal generated by the system control unit 21a based on the data recorded in the catalog area of the magneto-optical disk 1 is supplied to the display unit 23. Based on this display control signal, the display unit 23 displays time information such as the total reproduction time of the magneto-optical disk 1, the remaining time of the data or program being reproduced, the remaining recordable time, and the like during reproduction or recording. The track number etc. are displayed. Further, when the title of the disc itself, the title information of each data or program, and the data relating to the recording date of the data or the program are recorded on the magneto-optical disc 1, the data is selectively displayed on the display unit 23.

Further, the modulation processing performed by the decoder 16,
A decoder 24 for performing EFM demodulation processing and error correction processing on the digital data from the RF amplifier 18 is provided for the encoding processing. The digital data output from the decoder 24 is once written in the buffer memory 25 as described above. To this memory 25,
The digital data output from the decoder 24 is 1.4
Write at a transfer rate of 1 Mbit / sec, memory 25
The data stored in is read from the memory 25 at a transfer rate of 0.3 Mbit / sec. The digital data read from the memory 25 is supplied to the decompressor 26.

The decompressor 26 decompresses the data compressed to about ⅕ by the compressor 14 to about 5 times the data. Extender 2
The digital data signal expanded by 6 is D / A
It is supplied to the converter 27. The D / A converter 27 is an A / D
The digital audio signal output from the decompressor 26 is subjected to processing reverse to that of the converter 11 and output as an analog audio signal. The analog audio signal output from the D / A converter 27 is supplied to the selected terminal e of the switch 29 via the LPF 28. The output signal from the AGC circuit 10 is supplied to the selected terminal d of the switch 29 as described above. In the switch 29, the switch piece f is switched by the system control unit 21a, and the analog audio signal and A
The output signal from the GC circuit 10 is selectively output. The analog audio signal output from the switch 29 is supplied from the output terminal 37 as a line-out output signal A _OTL to an external acoustic device or the like, and is amplified by the amplifier 31 and output from the output terminal 39 to the headphone output signal A _OTL.
It is output as _OTL .

The digital audio signal output from the decoder 24 is output as it is as a digital signal from the output terminal 41 via the digital output interface circuit 40. The digital signal output from the digital input interface circuit 13 is supplied to the interface circuit 40. The digital signal supplied from the digital input interface circuit 13 is output from the output terminal 41 and serves as a monitor signal for recording.

Each such component is housed in a portable size cabinet together with mechanical parts such as a loading mechanism and a power source. A primary battery such as a dry battery or a secondary battery is used as a power source of the recording and / or reproducing apparatus configured as described above, and the DC voltage from the primary battery or the secondary battery is appropriately boosted and supplied to the controller 21 or the like. To be done.

The recording operation of the recording and / or reproducing apparatus configured as above will be described. When the recording key of the input unit 22 is operated, the system control unit 21a issues a control signal to start the operation of each unit of the recording and / or reproducing apparatus. After each operation such as focusing servo and tracking servo has started, input terminals 5 to 6
An input signal, for example, an analog audio signal, input from the A / D converter 1 via the LPF 9 and the AGC circuit 10.
It is supplied to 1 and converted into a 16-bit digital signal and digital audio signal. The digital audio signal is supplied to the compressor 14 and is compressed into a data amount of about 1/5 and then temporarily stored in the memory 15. The digital data once stored in the memory 15 is read by the memory control unit 21b and supplied to the encoder 16. The digital data supplied to the encoder 16 is subjected to EFM processing and error detection / correction coding processing and converted into recording data. The recorded data is
It is supplied to the magnetic head 4 via the head drive circuit 17. The magnetic head 4 applies a vertical magnetic field, which is modulated by a drive signal based on recording data, to the magneto-optical disk 1.
At this time, a light beam having an output level required for recording is emitted from the optical pickup 3 from the disk substrate side of the magneto-optical disk 1. As a result, the recording film of the magneto-optical disk 1 is heated to the Curie temperature or higher by the light beam emitted from the optical pickup 3, and at the same time, the modulated vertical magnetic field is supplied from the magnetic head 4. After that, the temperature of the recording film falls below the Curie temperature due to the relative movement of the light beam and the magneto-optical disk 1. At this time, the magnetization direction of the recording film is changed and determined according to the direction of the vertical magnetic field applied to the magneto-optical disk 1 by the magnetic head 4, and the data is recorded on the magneto-optical disk 1. In this way, the data of about 2 seconds (1 cluster) of the original analog audio signal is recorded on the magneto-optical disk 1 in about 0.4 seconds. Data recording on the magneto-optical disk 1 is intermittently performed with one cluster as a simple one.

During the recording operation, when the system control section 21a determines that a track jump has occurred due to vibration or the like, the optical pickup 3
The output level of the light beam emitted from is immediately lowered to an output level at which recording cannot be performed, and at the same time, the supply of recording data to the magnetic head 4 is stopped or the reading of digital data from the memory 15 is stopped. The input signal input from the input terminals 5 to 6 is stored in the memory 15 until the operation of accessing the position before the light beam emitted from the optical pickup 3 before the track jump occurs again is completed. Once the light beam access is complete,
The output level of the light beam emitted from the optical pickup 3 is raised to an output level required for recording, the supply of recording data to the magnetic head 4 is restarted, and the recording operation is started.

Regarding which part of the data recording area of the magneto-optical disk 1 to start recording, the input section 2
2 or the storage area or memory 15 or 25 in the system control unit 21a
System control unit 21a based on the data obtained by reading the catalog area stored in the dedicated storage area in
Set and controlled by. Further, during the recording operation, the data read from the inventory area and held in the system control unit 21a or the memory 15 or 25 is changed at any time according to the recording operation. When the recording operation of the data corresponding to all the input signals is completed, or the input unit 2
Before the disc cartridge is ejected from the recording and / or reproducing apparatus by operating the stop key of 2, the optical pickup 3 and the magnetic head 4 are accessed to the catalog area,
The data recorded in the catalog area of the magneto-optical disk 1 is updated, and after the updating operation is completed, the disk cartridge is ejected from the recording and / or reproducing apparatus.

Next, a basic reproducing operation of the recording and / or reproducing apparatus will be described. When the disc cartridge is loaded into the recording and / or reproducing device, the optical pickup 3 is sent in the inner circumferential direction of the magneto-optical disc 1 following the start-up operation of the spindle motor 2, the focusing servo, and the pull-in operation of the tracking servo. Magneto-optical disk 1
The catalog area of is read. At this time, the output level of the light beam emitted from the optical pickup 3 to the magneto-optical disk 1 is such that data cannot be recorded, in other words, the temperature of the recording film cannot be heated to the Curie temperature. It is set. The data recorded in the catalog area read by the optical pickup 3 is stored in the storage area in the system control unit 21a or the dedicated storage area in the memory 15 or 25.

Next, the optical pickup 3 is attached to the magneto-optical disk 1.
To the data recording area to read the data recorded in the data recording area. Which part of the data recording area to read the data recorded in and in what order is controlled by the system control part 21a based on an input signal input from the input part 22. Optical pickup 3
The output signal from the photodetector is supplied to the RF amplifier 18, and as described above, signals such as a focusing error signal and a tracking error signal are generated and an RF signal is generated. Any one of a focusing error signal, a tracking error signal, an RF signal, and a synchronization signal extracted from address data is supplied to the servo control circuit 20, and the servo control circuit 20 causes the focusing servo signal, the tracking servo signal, and the spindle servo. Signals and feed signals are generated.

Focusing servo and tracking servo are performed by supplying the focusing servo signal and the tracking servo signal to the actuator of the optical pickup 3. The spindle servo is performed by supplying the spindle servo signal to the spindle motor 2. The RF signal is supplied to the decoder 24 for EF.
M demodulation and error correction processing is performed. The address data decoded by the address decoder 19 is supplied to the system control unit 21a of the controller 21 via the decoder 24. Based on the supplied address information, the system control unit 21a controls the reproduction position of the optical pickup 3 in the radial direction of the magneto-optical disk 1. The system control unit 21a manages the reproduction position on the recording track of the magneto-optical disk 1 scanned by the optical pickup 3 using the reproduced address information.
Data reading from the magneto-optical disk 1 is performed intermittently in units of one cluster. The digital data output from the decoder 24 is temporarily stored in the memory 25. The memory control unit 21b writes digital data in the memory 25 at a transfer rate of 1.41 Mbit / sec unless a track jump in which the reproduction position moves due to vibration or the like occurs during the reproduction operation.
Digital data written in the memory 25 is 0.3M
It is read from the memory 25 at a transfer rate of bits / sec.
The memory control unit 21b prevents the data stored in the memory 25 from falling below a predetermined amount.
Controls the writing of digital data to. Memory 2
When the amount of data in 5 is a predetermined amount or more, the reading of data from the magneto-optical disk is stopped, that is, the so-called pause state. When the system controller 21a determines that a track jump has occurred during the reproducing operation, the memory controller 21b causes the decoder 24 to operate.
The writing of the digital data output from the memory 25 to the memory 25 is stopped, and the memory 25 is controlled so that only the digital data is transferred from the memory 25 to the decompressor 26. After that, after the access to the position of the light beam emitted from the optical pickup 3 to the magneto-optical disk 1, that is, the reproduction position before the track jump occurs, the digital data output from the decoder 24 is stored in the memory 25. The write operation is restarted. The digital data stored in the memory 25 is read out, decoded, and output from the output terminals 30 and 32 or the digital signal as it is until the reproduction position correction operation is completed.

The digital data read from the memory 25 is supplied to the decompressor 26, and the digital data is decompressed. The digital audio signal output from the expander 26 is supplied to the D / A converter 27 and converted into an analog audio signal, and the output terminal 30 or 32 is output.
Is output to an external audio device such as an external amplifier circuit.

Whether the analog audio signal via the LPF 28 is output from the output terminal 30 or the output terminal 32 is determined by switching the switch 29 and the switch piece f by the system controller 21a. Here, the output signal from the AGC circuit 10 via the switch 29 is an audio monitor signal at the time of recording, and the analog signal via the LPF 28 is a reproduction output signal. The system control unit 21a also controls whether an analog signal is output from the output terminal 30 or 32 or a digital signal is output from the output terminal 41.

In this reproducing operation, the memory control section 21b ensures that during the normal reproducing operation, the memory 25 stores more data than the data amount corresponding to the minimum necessary time required for correcting the reproducing position. Then, write control of the memory 25 is performed. The memory control unit 21b causes the system control unit 21a to generate a control signal when the amount of data in the memory 25 becomes equal to or less than a predetermined amount, so that the optical pickup 3 intermittently reads data from the magneto-optical disk 1. Then, the digital data from the decoder 24 is written in the memory 25. If a DRAM having a storage capacity of 1 Mbit is used, the memory 2
The time required to write the digital data to the full 5 is about 0.9 seconds, and this digital data corresponds to an analog signal of about 3 seconds. That is, when the digital data is stored in the memory 25 to the full, even if an output signal is not supplied from the optical pickup 3 that has read the magneto-optical disk due to vibration or the like, an analog signal as a reproduction signal is output for about 3 seconds. From 30, 32, the digital signal can be continuously output from the output terminal 41. In this embodiment, since the DRAM having the storage capacity of 4 Mbits is used as the memory 25, the reproduction signal can be continuously output from the output terminal 30 or 32 for about 12 seconds. In the meantime, the reproduction position on the disc by the optical pickup 3 is again accessed to the position before the track jump, and the reading of data from the magneto-optical disc 1 is restarted to output the analog audio as a reproduction signal from the output terminal 30 or 32. It is possible to prevent the signal and the digital audio signal output from the output terminal 41 from being interrupted.

After the reproduction operation of all the data recorded on the magneto-optical disk 1 is completed, or when the stop key of the input unit 22 is operated, the reproduction operation is stopped and the disk cartridge is ejected from the recording / reproducing apparatus. To be done.

Next, the reading control of the system control section 21a, which is the subject matter of the present invention, will be described with reference to the flowchart of FIG. First, the system control unit 21
In step S1, a controls the servo control circuit 20 to move the optical pickup 3 in the radial direction of the magneto-optical disk 1 to read data from the magneto-optical disk 1.

Next, the system control section 21a
In step S2, the decoder 24 is made to perform the decoding process as described above. In step S3, the system control unit 21a causes the digital data decoded by the decoder 24 to be written in the memory 25.
In step S4, whether or not the digital data written in the memory 25 in step S3 has been written until the writable area of the memory 25 is exhausted is determined by, for example, the memory control unit 21b using the write pointer of the memory 25 as the final address of the memory 25. It can be determined by determining whether they match. If digital data is written until the memory 25 is full in step S4, the process proceeds to step S5 and the memory 2
If the digital data has not been written in 5 until it is full, the process returns to step S1.

In step S5, the system controller 21a stops the reading operation of the magneto-optical disk 1 by the optical pickup 3 and the operation of the servo control circuit 20 based on the determination result in step S4.

In step S6, the system controller 21a starts reading the digital data written from the memory 25. The read digital data is supplied to the decompressor 26 as described above, and the decompressor 26 outputs about 5
The data length is doubled. The expanded digital signal is converted into an analog signal by the D / A converter 27 and output from the output terminal 30 or 32.

In step S7, it is determined whether or not the remaining data in the memory 25 obtained by subtracting the data read from the memory 25 in step S6, in other words, the amount of data held in the memory 25 is equal to or less than a predetermined amount. Determine. As a method of determining whether or not the amount of data held in the memory 25 has become equal to or less than a predetermined value, for example, the position of the read pointer of the memory 25 is read by the memory control unit 21b. In step S7,
When it is determined that the amount of data held in the memory 25 has become equal to or less than the predetermined amount, the process returns to step S1.
If it is determined that the amount is not less than or equal to the predetermined amount, the process returns to step S6 to continue reading the data from the memory 25. In the case of returning to step S1, after the servo control circuit 20 is operated again, the magneto-optical disk 2 is moved linearly according to the position of the optical pickup 3 on the magneto-optical disk 1 based on the output signal from the optical pickup 3. The spindle motor 2 is rotated so as to be constant. After the start-up operations are completed, the reading operation of the magneto-optical disk 1 is restarted by the optical pickup 3 and the step S
Move to 1.

In this way, the system control unit 21
For a, the read operation by the optical pickup 3 is not restarted unless the data amount of the data held in the memory 25 reaches a predetermined data amount. In other words, the servo control circuit 20 is still in the stopped state. That is, the power consumption in the servo control circuit 20 can be reduced.

The servo control circuit 20 performs the tracking servo, the focus servo, the spindle servo of the spindle motor 2 and the sled servo for moving the optical pickup 3 to the target track of the magneto-optical disk 1 as described above. In this embodiment, the system control unit 21a may limit and control the operation of the servo control circuit 20 until the data amount of the data held in the memory 25 reaches a predetermined data amount.

For example, the spindle motor 2 uses the servo control circuit 2 so that the magneto-optical disk 1 rotates at a constant linear velocity.
Although controlled by the spindle servo system of 0, the spindle motor 2 is controlled so that the magneto-optical disk 1 has a constant angular velocity by switching the spindle servo system. For example, a constant drive signal is supplied to the spindle motor 2 so that the magneto-optical disk 1 rotates at a constant angular velocity.
At the same time, the tracking servo system of the servo control circuit 20 is turned off and the tracking servo of the optical pickup 3 is turned off. The focus servo system of the servo control circuit 20 supplies a drive signal to the actuator of the optical pickup 3 to the extent that the focus servo of the optical pickup 3 is not displaced, thereby performing the focus servo.

The system control section 21a can detect the output level of the light beam emitted from the optical pickup 3 as a focus error signal in addition to stopping the operation of the servo control circuit 20, and the focus servo system of the servo control circuit 20. Decrease the focus servo to the extent that it can be used. As described above, the focus servo is operated under the minimum operable condition so that the read operation by the optical pickup 3 can be restarted quickly. This is because if the focus servo system is also turned off, it will take time before the reading operation is restarted by the optical pickup 3. However, it goes without saying that the focus servo system of the servo control circuit 20 may be turned off if necessary. Further, the system control unit 21a stops the clock pulse supplied to the decoder 24 while the decoder 24 is not required for any operation while the data is being read from the memory 25.

By turning off the servo control circuit 20 as described above, the power consumption can be greatly improved. One of the reasons for this is that the electromagnetic actuator is used as the actuator of the optical pickup 3 controlled based on each servo signal from the servo control circuit 20. As a result, the life of the primary battery or the secondary battery as a power source can be extended, and the device can be used for a long time.

In the above-mentioned embodiment, the case where the recording memory 15 and the reproducing memory 25 are used as the memories has been described as an example, but the memory may be one. This is because normally the recording operation and the reproducing operation are not performed at the same time.

Further, although the present embodiment has been described on the premise of a portable recording and / or reproducing apparatus using a primary battery or a secondary battery as the power source of the apparatus, the single phase 100 is used as the power source.
It may be applied to a recording and / or reproducing apparatus using V. In that case, not only the power consumption can be reduced, but also the heat generation in the device can be reduced, and the thermal adverse effect on the magneto-optical disk can be reduced.

Other than the above, various modifications are possible without departing from the spirit of the present invention.

[0082]

The recording and / or reproducing apparatus using the disk-shaped recording medium according to the present invention has a first period in which the data recorded in the recording medium is read by the optical head and the read data is written in the memory. The data recorded on the recording medium is intermittently read by alternately setting the second period in which the reading of the data recorded on the recording medium by the optical head is stopped and only the data stored in the memory is read. Since the servo control operation is stopped at least during the second period, useless power consumption can be suppressed. As a result, it becomes possible to extend the life of the battery used as the drive power source of the device.

[Brief description of drawings]

FIG. 1 is a block diagram of a recording and / or reproducing apparatus according to the present invention.

FIG. 2 is a flowchart illustrating a control operation of the recording and / or reproducing apparatus shown in FIG.

[Explanation of symbols]

1 Magneto-optical disk 2 Spindle motor 3 Optical pickup 4 Magnetic head 9 LPF 10 AGC circuit 11 A / D converter 14 Compressor 15 Buffer memory 16 Encoder 17 Head drive circuit 18 RF amplifier 19 Address recorder 20 Servo control circuit 21 System controller 21a System control unit 21b Memory control unit 22 Input unit 24 Decoder 25 Buffer memory 26 Expander 27 D / A converter 28 LPF

Claims (10)

[Claims] 1. An optical head for irradiating a disc-shaped recording medium with a light beam to read data recorded on the disc-shaped recording medium, and an error signal generated based on an output signal from the optical head. Servo means for controlling the servo of the optical head, and temporarily stores the data read from the optical head,
A memory for reading data stored at a reading speed slower than a writing speed of data read from the disk-shaped recording medium by the optical head, and a data read by the optical head for recording on the disk-shaped recording medium. A first period for writing the data read in the memory and a second period for stopping the reading of the data recorded on the disk-shaped recording medium by the optical head and only reading the data stored in the memory. Controlling the optical head and the memory so as to intermittently read the data recorded on the disk-shaped recording medium by alternately setting them, and stopping the operation of the servo means during the second period. And / or reproducing apparatus for the disc-shaped recording medium. 2. The control means includes a memory control section for writing data read from the optical head to the memory and controlling reading data stored in the memory, and the memory control section stores the data in the memory. When the memory control unit detects that the data amount of the stored data is below a predetermined capacity, the control unit issues a control signal to restart the reading operation of the optical head and the servo operation of the servo unit. A recording and / or reproducing apparatus for the disc-shaped recording medium according to claim 1. 3. A disk-shaped recording medium is provided with a rotation driving means at a constant linear velocity, and the control means controls the rotation driving means so that the disk-shaped recording medium rotates at a constant angular velocity during the second period. A recording and / or reproducing apparatus for the disc-shaped recording medium according to claim 1. 4. An optical head for irradiating a disk-shaped recording medium, on which a digital audio signal is compressed and recorded, with a light beam to read data recorded on the disk-shaped recording medium, and a constant linear velocity for the disk-shaped recording medium. A spindle motor that is rotationally driven by the optical head, servo means that performs servo control of the optical head and the spindle motor based on an error signal generated based on the output signal from the optical head, and an output signal from the optical head. A decoding processing means for performing a decoding processing, a memory for temporarily storing the data output from the decoding processing means, and a memory for reading the stored data at a reading speed slower than the writing speed of the data output from the decoding means, By reading the data recorded on the disk-shaped recording medium by the optical head, A first period for writing the read data to the memory and a second period for stopping the reading of the data recorded on the disk-shaped recording medium by the optical head and reading only the data stored in the memory. A control means for controlling the optical head and the memory so as to intermittently read the data recorded on the disk-shaped recording medium by alternately setting them and stopping the operation of the servo means during the second period; A recording and / or reproducing device for a disc-shaped recording medium. 5. The control means comprises a memory control section for writing data read from the optical head to the memory and controlling reading of data stored in the memory, and is stored in the memory. When the memory control unit detects that the data amount of the stored data is below a predetermined capacity, the control unit issues a control signal to restart the reading operation of the optical head and the servo operation of the servo unit. A recording and / or reproducing apparatus for the disk-shaped recording medium according to claim 4. 6. The recording and / or recording of the disk-shaped recording medium according to claim 4, wherein the control means controls the rotation driving means so that the disk-shaped recording medium rotates at a constant angular velocity during the second period. Or a playback device. 7. A recording and / or reproducing apparatus for a disk-shaped recording medium according to claim 4, wherein the control means stops the supply of the clock signal to the decoding processing means during the second period. 8. A recording and / or reproducing apparatus for a disk-shaped recording medium according to claim 4, wherein the control means controls the optical head to be in a pause state during the second period. 9. The optical head comprises a light source for emitting a light beam for irradiating the disc-shaped recording medium, and the control means outputs the light beam for irradiating the disc-shaped recording medium during the second period. The recording and / or reproducing apparatus for a disk-shaped recording medium according to claim 4, wherein the level is lowered to a level required for servo control by the servo means. 10. An optical head for irradiating a disk-shaped recording medium, on which a digital audio signal is compressed and recorded, with a light beam to read data recorded on the disk-shaped recording medium, and a constant linear velocity for the disk-shaped recording medium. A spindle motor that is rotationally driven by the optical head, an error signal generating unit that generates a signal for generating a focus error signal, a tracking error signal, and a spindle servo signal based on the output signal from the optical head, and the error signal generating unit. A focus servo signal is generated based on the output focus error signal, a tracking servo signal is generated based on the tracking error signal, and a spindle servo signal is generated based on a signal for generating a spindle servo signal. The focus servo signal and the above Servo means for supplying a tracking error signal to the optical head to perform focus servo and tracking servo, and also to supply the spindle servo signal to the spindle motor to perform spindle servo, and a decoding process for an output signal from the optical head. And a memory for temporarily storing the data output from the decoding means and reading the stored data at a reading speed slower than the writing speed of the data output from the decoding means. A first period in which the head reads data recorded on the disk-shaped recording medium and writes the read data in the memory, and the optical head stops reading the data recorded in the disk-shaped recording medium to the memory. Of stored data And a second period during which the optical head and the memory are controlled so as to intermittently read the data recorded on the disk-shaped recording medium, and the servo means is operated during the second period. A recording and / or reproducing apparatus for a disk-shaped recording medium, comprising a control means for controlling only the focus servo to operate.