JP3107116B2 - Disc playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk reproducing apparatus, and more particularly to a disk reproducing apparatus which is suitably applied to a case where pitch control for changing a reproducing speed is performed.

[0002]

2. Description of the Related Art Conventionally, for example, in a CD (compact disk) player, pitch control for changing a reproduction speed is performed by controlling the number of revolutions of a spindle motor for rotating a CD.

The applicant of the present invention compresses audio data, intermittently records the data on a small disk having a diameter of 64 mm, reads data intermittently from the small disk, and temporarily stores the data in a buffer memory. There has been proposed a disk recording / reproducing apparatus which appropriately reads data from the memory and expands the data to reproduce the original audio data (for example, Japanese Patent Application No. 22-22 / 1990).
No. 1725).

[0004] When an audio signal is reproduced from such a small disk, pitch control for changing the reproduction speed may be performed. In this case, a conventional CD player is used. It is conceivable that the pitch control method is adopted also in this disk recording / reproducing apparatus. That is, also in this disk recording / reproducing apparatus, pitch control can be performed by controlling the number of rotations of the spindle motor for rotating the disk.

[0005]

However, as is conventionally known, in the method of controlling the rotation speed of the spindle motor to perform pitch control, the range of pitch control speed is, for example, normal. It can only change about ± 10% of the reproduction speed, and has a very narrow defect. The reason is that when changing the number of rotations of the disk, the rotation speed servo must also be changed,
In the range where the change in the rotation speed is small, the servo constant can be easily set and the speed servo can be performed relatively stably. However, when the rotation speed is to be changed greatly like double speed, the servo cannot be changed. This is because the pitch becomes stable and pitch control cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device capable of stably controlling the pitch at twice or more speeds by making use of the characteristics of the above-described reproducing apparatus for a disk smaller than a CD.

[0007]

A CD player reproduces data in real time. Therefore, pitch control can be performed only by controlling the number of revolutions of a spindle motor for driving a disk. Can not. However, in the case of the above-mentioned small disk reproducing apparatus, data is read out intermittently, temporarily written into the buffer memory, and data is read out therefrom appropriately to expand the data. Just change the pitch control.

[0008]

That is, in order to solve the above-mentioned problems, a disk reproducing apparatus according to the present invention comprises a spindle motor for rotating a disk on which data is compressed and recorded at a predetermined rotational speed, and a disk drive comprising: ,
Means for intermittently reading the data, a buffer memory for temporarily storing intermittent data read from the disk, a memory controller for controlling writing and reading of the buffer memory, and data from the buffer memory. Expanding means for reading out and expanding the data based on a predetermined clock to generate continuous original data, clock generating means for generating the predetermined clock, and a clock for changing the frequency of the clock from the clock generating means Frequency varying means, provided to the extending means.
Clock is changed by the clock frequency variable means.
The data from the buffer memory
The read speed is changed, and the read speed changes.
Said buffer memory by said memory controller
Depending on the write and read control means for reading from the intermittently disk the data, without changing the rotational speed of the spindle motor, wherein the benzalkonium changing the timing of the intermittent read from the disk And

[0009]

According to the present invention having the above structure, the extension means 20 is provided.
When the frequency of the clock supplied to the buffer memory is changed, the speed of reading data from the buffer memory is changed accordingly, and the data is expanded by the expansion means 20 based on this clock, and pitch control is performed. Therefore, pitch control can be performed without changing the rotation speed of the spindle motor 3 for driving the disk.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the present invention in which audio data is compressed and recorded on a disk smaller than the aforementioned CD,
This is an embodiment in which the present invention is applied to a disk recording / reproducing apparatus which expands data during reproduction and reproduces original audio data.

In FIG. 1, reference numeral 1 denotes an optical disk. The outer diameter of the disk 1 of this example is 64 mm.
The recording tracks are formed spirally at a pitch of, for example, 1.6 μm. The disk 1 is driven to rotate by the spindle motor 3, and is controlled by the servo circuit 80 to rotate at a constant linear velocity, for example, 1.2 to 1.4 m / s. The audio information is converted into a digital signal on the disk 1 and is recorded after being compressed, so that the target information can be recorded and reproduced for 130 Mbytes or more.

In this example, the disc 1 can be two or more different types of discs. For example, a read-only optical disk in which a signal is recorded by a pit train made by an injection mold or the like, and a rewritable magneto-optical disk having a magneto-optical recording film and capable of recording, reproducing, and erasing are considered.

Further, a pre-groove for light spot control (for tracking control) is formed on the disc 1 in advance. In this case, in particular, in this example, the pre-groove is provided with a wobbling signal for tracking. The absolute address code is recorded in a superimposed manner. The disc 1 is housed in a disc cartridge 2 to prevent dust and prevent scratches.

[Recording System of Recording / Reproducing Apparatus] The embodiment of the recording / reproducing apparatus shown in FIG. 1 is designed so that the configuration can be simplified as much as possible by using an IC. First, the time of recording on the magneto-optical disk will be described. At the time of recording and at the time of reproduction, each circuit section is switched in mode by a mode switching signal from a system controller 100 constituted by using a microcomputer. A key input operation unit 110 is connected to the system controller 100, an operation mode is designated by an input operation on the key input operation unit 110, and a reproduction speed is set by the pitch control key.

The analog audio signals of the left and right channels through the input terminal 6 are supplied to the A / D converter 1
At 0, sampling is performed at a sampling frequency of 44.1 kHz, and each sampled value is converted to a 16-bit digital signal. The 16-bit digital signal is supplied to the data compression / expansion processing circuit 20. The data compression / expansion processing circuit 20 functions as a data compression circuit during recording, and functions as a data expansion circuit during reproduction. For data compression and decompression, this processing circuit 20
A buffer memory (not shown) is provided.

In the case of this example, the data compression / expansion processing circuit 20 compresses the input digital data by, for example, about 1/5. Various data compression methods can be used. For example, ADPCM (Adaptive Delta Pulse Code Modulat
ion) can be used. Further, for example, the input digital data is divided into a plurality of bands so that the higher the band, the wider the bandwidth, and a plurality of samples (the number of samples is better to be the same in each band) for each divided band. It is also possible to use a method in which blocks are formed, orthogonal transform is performed for each block in each band, coefficient data is obtained, and bit allocation is performed for each block based on the coefficient data. In this case, the data compression method takes into account the characteristics of human perception of sound and can perform data compression with high efficiency (see Japanese Patent Application No. 1-278207).

The digital data DA from the A / D converter 10 is data-compressed to 1/5 by the data compression processing in the data compression / decompression processing circuit 20, and the data da is compressed by the memory controller 30.
Is transferred to the buffer memory 31 controlled by. In this example, a DRAM having a capacity of 1 M to 4 M bits is used as the buffer memory 31.

The memory controller 30 sends a predetermined amount of compressed data da from the buffer memory 31 at intermittent recording timings, unless a track jump occurs in which the recording position on the disk 1 jumps due to vibration or the like during recording. The data is read at a transfer speed that is about five times the writing speed, and the read data is transferred to the ECC and modulation / demodulation processing circuit 40.

When it is detected that a track jump has occurred during recording, the data transfer to the processing circuit 40 is stopped, and the compressed data da from the processing circuit 20 is stored in the buffer memory 31. Then, when the recording position is corrected, control is performed so that data transfer from the buffer memory 31 to the circuit 40 is restarted.

The detection of whether or not a track jump has occurred can be performed, for example, by providing a vibrometer in the apparatus and detecting whether or not the magnitude of the vibration is such as to cause a track jump. Further, as described above, the absolute address code is recorded on the disk 1 of this example so as to be superimposed on the wobbling signal for tracking control when the pregroove is formed. Therefore, it is possible to read the absolute address code from the pregroove at the time of recording and detect a track jump from the decoded output. Alternatively, a track jump may be detected by ORing the absolute address code with the vibrometer.
When a track jump occurs, the power of the laser beam for magneto-optical recording is reduced or the power is set to zero.

The correction of the recording position when a track jump occurs can be performed using the above-mentioned absolute address code.

As understood from the above, the data capacity of the buffer memory 31 in this case is as follows.
At least, a capacity capable of storing the compressed data da corresponding to the time from the occurrence of the track jump to the time when the recording position is correctly corrected is required. In this example, the capacity of the buffer memory 31 is 1 M to 4 M bits as described above, and this capacity is selected as having a margin so as to sufficiently satisfy the above conditions.

In this case, the memory controller 30
Performs a memory control so that data stored in the buffer memory 31 is reduced as much as possible during normal operation during recording. For example, when the data amount of the buffer memory 31 becomes equal to or more than a predetermined amount, a predetermined amount of data, for example, 32 sectors (one sector corresponds to one CD-R)
Only the data of the OM sector (approximately 2 Kbytes) is read from the buffer memory 31, and the memory control is performed such that a write space of a predetermined data amount or more is always secured.

The ECC and modulation / demodulation processing circuit 40 functionally includes a data encoding / decoding circuit 41, a recording encoding circuit 42, a reproduction decoding circuit 43, and a timing signal generation circuit 44. The timing signal generation circuit 44 includes a crystal oscillator as a reference oscillator. Various timing signals from the timing signal generation circuit 44 are transmitted to the data encoding / decoding circuit 4.
1. While being supplied to the recording encoding circuit 42 and the reproduction decoding circuit 43, it is also supplied to the memory controller 30 and the processing circuit 20, and further, the clock of the A / D converter 10 is also supplied. However, as will be described later, the data compression / decompression processing circuit 20 during reproduction and the D / A converter 1
As the clock to 1, the clock frequency control circuit 90
Is supplied via

The data encoding / decoding circuit 41 of the processing circuit 40 functions as an encoding circuit at the time of recording, and encodes the compressed data da transferred from the buffer memory 31 into data having a CD-ROM sector structure.
Note that data including audio data for 32 sectors is hereinafter referred to as a cluster.

This data encoding / decoding circuit 41
Is output to the recording encoding circuit 42. This recording encoding circuit 4
In 2, the data is subjected to an encoding process for error detection and correction, and a modulation process suitable for recording, in this example, an EFM encoding process. In this example, CIRC (Cross Interleaved Reed-Solomon Code) is used as the code for error detection and correction. However, since the recording data is intermittent data in cluster units, an improved CIRC encoding process is performed. Will be

The encoded data from the recording encoding circuit 42 is supplied to the magnetic head 4 via the magnetic head driving circuit 50. Magnetic head drive circuit 5
Numeral 0 drives the magnetic head to apply a modulation magnetic field according to the recording data to the disk 1 (magneto-optical disk).
The recording data supplied to the head is in cluster units, and recording is performed intermittently in cluster units.

The disk 1 is stored in the cartridge 2, but when the disk 1 is loaded in the apparatus, the shutter plate is opened and the disk 1 is exposed from the shutter opening. Then, the rotation shaft of the disk drive spindle motor 3 is inserted and connected to the spindle insertion opening, and the disk 1 is driven to rotate. In this case, the rotation speed of the spindle motor 3 is controlled by the servo control circuit 80 so as to rotate the disk 1 at a linear speed of 1.2 to 1.4 m / s.

The magnetic head 4 faces the disk 1 exposed from the shutter opening of the cartridge 2. An optical head 5 is provided at a position facing the surface of the disk 1 opposite to the surface facing the magnetic head. The optical head 5 includes, for example, a laser light source such as a laser diode, a collimator lens, an objective lens, optical components such as a polarizing beam splitter and a cylindrical lens, a photodetector, and the like. Laser light of a constant power larger than the time is irradiated. By this light irradiation and the modulation magnetic field by the magnetic head 4, data is recorded on the disk 1 by thermomagnetic recording. And the magnetic head 4
The optical head 5 and the optical head 5 are both configured to be movable along the radial direction of the disk 1.

At the time of this recording, the optical head 5
Is output to the absolute address decoding circuit 7 via the RF circuit 60.
0, the absolute address code from the pre-groove of the disk 1 is extracted and decoded. Then, the decoded absolute address information is supplied to the recording encoding circuit 42, inserted into the recording data as the absolute address information, and recorded on the disk. The absolute address information from the absolute address decoding circuit 70 is also supplied to the system controller 100, and is used for recognition of a recording position and position control as described above.

Further, a signal from the RF circuit 60 is supplied to a servo control circuit 80, and a control signal for a constant linear velocity servo of the motor 3 is formed from a signal from a pre-groove of the disk 1, so that the motor 3 is controlled in speed. Is done.

[Reproducing System of Recording / Reproducing Apparatus] The apparatus of this example is capable of reproducing two types of discs, a read-only optical disc and a rewritable magneto-optical disc, and identifies these two discs. For example, when the disc cartridge 2 is loaded in the apparatus, the discrimination can be performed by detecting the identification concave hole provided to each disc cartridge 2. In addition, since the light reflectance is different between the read-only disc and the rewritable disc, two discs can be identified from the amount of received light. Although not shown, the discrimination outputs of these two types of disks are supplied to the system controller 100.

The disc loaded in the apparatus is driven to rotate by a spindle motor 3. The motor 3 is controlled by the servo control circuit 80 in the same manner as during recording.
The rotation speed is controlled by a signal from the pre-groove so that the disk 1 is kept at the same speed as when recording, that is, at a linear speed of 1.2 to 1.4 m / s.

At the time of reproduction, the optical head 5 detects a focus error by, for example, an astigmatism method by detecting reflected light of a laser beam applied to a target track.
For example, a tracking error is detected by a push-pull method, and in the case of a read-only optical disk, a reproduction signal is detected by utilizing a light diffraction phenomenon in a pit row of a target track, and in the case of a rewritable magneto-optical disk. Detects a reproduced signal by detecting a difference in the polarization angle (Kerr rotation angle) of the reflected light from the target track.

The reading of the reproduction data from the disk 1 by the optical head 5 is performed intermittently by a fixed amount under the control of the system controller 100, in this example, in cluster units.

The output of the optical head 5 is supplied to an RF circuit 60. The RF circuit 60 extracts the focus error signal and the tracking error signal from the output of the optical head 5 and supplies them to the servo control circuit 80, and also outputs the reproduced signal to the servo control circuit 80.
It is converted into a value and supplied to the reproduction decoding circuit 43 of the processing circuit 40.

The servo control circuit 80 controls the focus of the optical system of the optical head 5 so that the focus error signal becomes zero, and controls the optical system of the optical head 5 so that the tracking error signal becomes zero. Perform tracking control.

Further, the RF circuit 60 extracts the absolute address code from the pre-probe and supplies it to the absolute address decoding circuit 70. Then, the absolute address information from the decoding circuit 70 is supplied to the system controller 100, and is used by the servo control circuit 80 for controlling the reproduction position of the optical head 5 in the disk radial direction. Further, the system controller 100 can also use the address information in sector units extracted from the reproduction data to manage the position on the recording track where the optical head 5 is scanning.

At the time of this reproduction, as will be described later,
The compressed data read from the disk 1 is written to the buffer memory 31 and read and decompressed. Due to the difference in the transmission rates of the two data, the timing of intermittent data reading from the disk 1 by the optical head 5 is as follows. For example, it is controlled by the system controller 100 while monitoring the data stored in the buffer memory 31 by the memory controller 30 so as not to be less than a predetermined amount.

The reproduction decoding circuit 43 of the processing circuit 40
In response to the binary reproduced signal from the RF circuit 60, processing corresponding to the recording encoding circuit 42, that is, EFM decoding processing, decoding processing for error detection and correction, interpolation processing, and the like are performed. The output data of the reproduction decoding circuit 43 is supplied to the data encoding / decoding circuit 41.

The data encoding / decoding circuit 41
At the time of reproduction, it functions as a decoding circuit, and decodes data having a sector structure of the CD-ROM into compressed data. The output data of the data encoding / decoding circuit 41 is transferred to the buffer memory 31 controlled by the memory controller 30, and is written at a predetermined writing speed. The clock for this writing is supplied from the processing circuit 40 to the memory controller 30.

At the time of this reproduction, if there is no track jump in which the reproduction position jumps due to vibration or the like during the reproduction, the memory controller 30 supplies the data from the data compression / expansion processing circuit 20 side. Based on the data read request signal, the compressed data from the data encoding / decoding circuit 41 is sequentially read from the buffer memory 31 at a transfer speed of about 1/5 times the writing speed, and the read data is compressed. /
The data is transferred to the decompression processing circuit 20. In this case, as described above, the memory controller 30 controls writing / reading of the buffer memory 31 so that the amount of data stored in the buffer memory 31 does not fall below a predetermined value.

When it is detected that a track jump has occurred during reproduction, the system controller 100
Stops writing of data from the circuit 40 to the buffer memory 31 and only transfers data to the data compression / decompression processing circuit 20. Then, when the reproduction position is corrected, control is performed so that data writing from the circuit 40 to the buffer memory 31 is restarted.

The detection of whether or not a track jump has occurred is performed by, for example, a method using a vibrometer or an absolute address code recorded on a pregroove of an optical disc by superimposing it on a wobbling signal for tracking control, as in the recording. The method used (that is, the method using the decoded output of the absolute address decoding circuit 70) or the method of detecting the track jump by taking the OR of the vibrometer and the absolute address code can be used. Further, at the time of this reproduction, as described above, the absolute address information and the address information in sector units are extracted from the reproduced data, and thus can be used.

As will be understood from the above, the data capacity of the buffer memory 31 at the time of this reproduction corresponds to the time from the occurrence of a track jump to the correct correction of the reproduction position. A minimum capacity that can always store data is required. This is because, with such a capacity, even if a track jump occurs, data can be continuously transferred from the buffer memory 31 to the data compression / decompression processing circuit 20. The 1 M to 4 M bits as the capacity of the buffer memory 31 in this example is selected as a sufficient capacity so as to sufficiently satisfy the above conditions.

As described above, during normal operation, the memory controller 30 controls the memory so that the buffer memory 31 stores predetermined data more than the necessary minimum as much as possible. In this case, for example, when the data amount of the buffer memory 31 becomes equal to or less than a predetermined amount, a data read request is issued to the system controller 100, and the optical head 5 intermittently captures data from the disk 1. Then, data is written from the circuit 40, and memory control is performed so that a read space of a predetermined data amount or more is always secured.

The data compression / decompression processing circuit 20 functions as a data decompression circuit at the time of reproduction, fetches ADPCM data from the buffer memory 31 into the buffer memory (not shown), and performs a reverse conversion to the data compression processing at the time of recording. Perform processing and extend about 5-fold.

The digital audio data from the data compression / expansion processing circuit 20 is supplied to the D / A converter 11, returned to a two-channel analog audio signal, and output from the output terminal 7. In this example,
The digital audio data before the D / A conversion can be directly output from the output terminal 8.

[Explanation of Pitch Control] As described above, at the time of reproduction, the memory controller 30
Reads compressed data from the buffer memory 31 based on a read request from the data compression / decompression processing circuit 20,
Transfer to the circuit 20. Then, as described above, the memory controller 30 constantly monitors the data amount of the buffer memory 31 so as not to be less than a predetermined amount, and the system controller 100 always monitors the buffer memory 31 based on the monitoring of the memory controller 30. The intermittent read from the disk is controlled so that a predetermined amount or more of data is stored.

The data compression / expansion processing circuit 20 takes in the compressed data into its built-in buffer memory, sequentially decompresses the data, and outputs it to the D / A converter 11. When the data amount in the built-in buffer memory reaches a predetermined amount, a read request is issued. The signal is output to the memory controller 30. When the transfer clock rate of the decompressed data output from the data compression / decompression processing circuit 20 to the D / A converter 11 changes, the output timing of the read request signal changes accordingly. Then, the timing of the intermittent reading from the disk 1 changes because of the control by the memory controller 30 to keep the amount of data stored in the buffer memory 31 substantially constant as described above. Therefore, pitch control can be performed by this. For example, data compression /
When the transfer clock rate of the decompressed data output from the decompression processing circuit 20 to the D / A converter 11 is doubled, the output timing of the read request is also doubled, and the intermittent read timing of the data in the cluster unit is adjusted accordingly. As a result, the playback speed becomes twice as fast as that at the time of playback at the normal speed (normal playback speed), and the playback time becomes 1/2.

As shown in FIG. 1, in this embodiment,
Data compression / expansion processing circuit 20 to D / A converter 1
1 is supplied from the clock frequency variable circuit 90. The clock frequency variable circuit 90 includes the circuit 4
The frequency of the clock from the timing signal generating circuit 44 of 0 is varied by a control signal for pitch control from the system controller 100. This pitch control amount can be changed by a pitch control key of the key input operation unit 110. As can be understood from the above description, the pitch control amount during reproduction can be changed by the variable operation of the clock frequency.

Hereinafter, the operation during reproduction including the pitch control will be described in more detail with reference to FIG.

At the time of reproduction, when the compressed data DTO is transferred from the processing circuit 40 to the buffer memory 31 and written therein, a transfer clock LRCK is supplied from the processing circuit 40 to the memory controller 30 and the data DTO is supplied to this clock. The data is written to the memory 31 in synchronization with LRCK. The clock LRCK is synchronized with a word, which is the minimum unit of data, and has a frequency of 44.1 kHz. That is, as shown in FIGS. 3A and 3B, the data DL of the left channel of the audio data and the data DR of the right channel of the audio data are synchronized with the clock DTO and equal to the sampling clock of the A / D converter 10. The data is transferred to and written to the address 31. Data DL and D
R is 16 bits, but includes about 5 words of the original audio data because it is compressed. The circuit 40 supplies a bit clock XBCK (FIG. 3C) having a frequency 64 times the frequency of the clock LRCK to the memory controller 3.
0 is supplied.

Then, the clock LRCK is supplied to the clock frequency variable circuit 90. This circuit 90 is constituted by a PLL circuit. That is, 91 is an integer multiple of the sampling frequency fs (= 44.1 kHz), and in this example, 102
An output signal of the VCO 91 is supplied to a variable frequency dividing circuit 92 by a variable frequency oscillator (hereinafter, referred to as a VCO) having a quadruple frequency as a free-running oscillation center frequency. The dividing ratio 1 / N of the variable dividing circuit 92 is determined by the system controller 10
This is set by setting the N value of the frequency division ratio 1 / N by the pitch control signal from 0.
At normal playback speed, N = 1024, and the frequency division ratio is set to 1/1024.

The output signal of the variable frequency dividing circuit 92 is supplied to a phase comparing circuit 93. And the clock from circuit 40
LRCK is supplied to the phase comparison circuit 93 and is compared in phase with the signal from the variable frequency dividing circuit 92. The comparison error is supplied to the VCO 91 via the low-pass filter 94, and the output clock is synchronized with the clock LRCK. Is controlled as follows.

The output clock of the VCO 91 is supplied to the frequency divider 9
In 5, the frequency is divided by 1/16. The output clock PTXBCK of the frequency dividing circuit 95 is further divided into 1/64 by the frequency dividing circuit 96 to obtain the output clock PTLRCK.
These output clock PTXBCK and output clock PTLRCK are
Data compression / expansion processing circuit 20 and D / A converter 1
1 is supplied.

In the case of the normal reproduction speed, since the frequency division ratio of the variable frequency dividing circuit 92 is 1/1024, the VCO 91
Is synchronized with the clock LRCK and the frequency is 1024 fs
Is obtained. Therefore, the output clock PTXBCK of the frequency divider 95 is a clock having a frequency of 64 fs. This is equal to the bit clock XBCK from the circuit 40. Further, the frequency of the output clock PTLRCK of the frequency dividing circuit 96 becomes fs and becomes equal to the clock LRCK.

Therefore, the data compression / decompression processing circuit 2
From 0, data is expanded based on a clock PTLRCK equal to the word clock LRCK, and the D / A converter 11 returns the audio data word to an analog signal using the clock PTLRCK as a sampling clock.

Next, when the pitch control key is operated to increase the pitch, the N value of the variable frequency dividing circuit 92 of the circuit 90 is adjusted by the system controller 100 to a value greater than 1024 according to the pitch control. Set to a number. Then, the frequency of the output clock of the VCO 91 becomes higher than 1024 fs, and the frequencies of the clocks PTXBCK and PTLRCK also become higher. For this reason, the speed at which data is transferred from the data compression / decompression processing circuit 20 to the D / A converter 11 increases, the frequency of the read request signal XARQ output from the circuit 20 to the memory controller 30 increases, and the circuit The timing of the data transfer to the memory 20 is faster.

Therefore, the data stored in the buffer memory 31 is read out faster than at the normal reproduction speed, and accordingly, the timing of the intermittent readout for reading out a certain amount of data from the disk 1 becomes faster. In this way, the reproduction speed increases in accordance with the pitch control amount as compared with the normal reproduction speed. In this case, since the frequency of the sampling clock of the D / A converter 11 becomes higher, the frequency of the reproduced audio signal also becomes higher than at the normal reproduction speed.

Next, when an operation is input by the pitch control key to lower the pitch, the N value of the variable frequency dividing circuit 92 of the circuit 90 is adjusted by the system controller 100 to a value smaller than 1024 according to the pitch control. Set to a number. Then, the frequency of the output clock of the VCO 91 becomes lower than 1024 fs, and the frequencies of the clocks PTXBCK and PTLRCK also become lower. Therefore, the speed at which data is transferred from the data compression / decompression processing circuit 20 to the D / A converter 11 is lower than that at the time of the normal reproduction speed.
The frequency of the read request signal XARQ output to 0 becomes low, and the timing of data transfer from the buffer memory 31 to the circuit 20 is delayed.

Therefore, the data stored in the buffer memory 31 is read out more slowly than at the normal reproduction speed.
The timing of intermittent read for reading data from the memory becomes slow. Thus, the reproduction speed becomes slower in accordance with the pitch control amount than the normal reproduction speed. In this case, since the frequency of the sampling clock of the D / A converter 11 becomes lower, the frequency of the reproduced audio signal also becomes lower than at the normal reproduction speed.

As described above, the pitch control for varying the reproduction time can be performed without changing the rotation speed of the spindle motor 3. In the case of this example, the variable pitch of the pitch control is equal to the variable pitch of the N value of the variable frequency dividing circuit 92.
It can be performed in 24 steps, and fine pitch control can be performed. Further, since it is not necessary to control the speed of the spindle motor 3 and the pitch can be controlled simply by changing the clock frequency, it has not been possible with a conventional CD player.
Reproduction at a reproduction speed that is significantly different from the normal speed, such as 1/2 speed, 2 times speed, and 3 times speed, can be performed stably.

In the above example, the intermittent reading of data from the disk is performed in units of one cluster. However, depending on the amount of pitch control, the disk may be intermittently read in this one intermittent reading. Alternatively, the amount of data read from the memory may be changed. For example, when the reproduction speed is twice the normal speed, two clusters are read in one intermittent read from the disk.

[0065]

As described above, according to the disk reproducing apparatus of the present invention, pitch control can be performed without changing the rotation speed of the spindle motor, so that pitch control can be performed stably. It is possible to enlarge the variable range of the pitch control.

Further, since the rotation speed of the spindle motor is not changed, there is an advantage that there is no change in the rotation noise or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a disk recording / reproducing apparatus according to the present invention.

FIG. 2 is a block diagram of an example of a main part of the present invention.

FIG. 3 is a timing chart for explaining a main part of the present invention.

[Explanation of symbols]

 Reference Signs List 1 disk 2 disk cartridge 3 spindle motor 5 optical head 11 D / A converter 20 data compression / expansion processing circuit 30 memory controller 31 buffer memory 40 ECC and modulation / demodulation processing circuit 44 timing signal generation circuit 90 clock frequency variable circuit 100 system controller

Claims (4)

(57) [Claims] A spindle motor for rotating a disk on which data is compressed and recorded at a predetermined rotation speed; a means for intermittently reading the data from the disk; an intermittent read from the disk; A buffer memory for temporarily storing data; a memory controller for controlling writing and reading of the buffer memory; and reading and expanding data from the buffer memory based on a predetermined clock to obtain continuous original data Extending means, clock generating means for generating the predetermined clock, and clock frequency varying means for varying the frequency of the clock from the clock generating means, wherein the clock supplied to the extending means is the clock frequency.
Said buffer in response to being changed by a number variable means
The speed of reading data from memory can be changed,
The memory controller according to the change of the ejection speed
Write and read control of the buffer memory
Flip and, means for reading the data from the intermittent disc without changing the rotational speed of the spindle motor, the disc reproducing apparatus characterized by varying the timing of the intermittent read from the disk. 2. The disk reproducing apparatus according to claim 1, wherein an output clock of said clock generating means is synchronized with a word which is a minimum unit of data. 3. The memory controller according to claim 1, wherein the memory controller monitors the number of data stored in the buffer memory, and performs writing / reading of the buffer memory so that the number of data always exceeds a predetermined value. Means for controlling and intermittently reading data from the disk, wherein the intermittent read timing is adjusted so that the number of data in the buffer memory always exceeds the predetermined value without changing the rotation speed of the spindle motor. A disk playback device to be controlled. 4. The disk reproducing apparatus according to claim 1, wherein an amount of read data for one intermittent read from said disk is changed in accordance with a frequency of a clock from said clock frequency varying means.