JPH1116266A - Disk recording and/or reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk recording/reproducing device capable of properly controlling a loop gain according to the rotational speed of an optical disk. SOLUTION: For performing reading from an optical disk, the optical disk is controlled at a constant linear velocity by a CLV(Constant Linear Velocity) control means and, for performing no reading from the optical disk, the optical disk is controlled at a constant angular velocity by a CAV(Constant Angular Velocity). For preventing a difference in previous rotational speed when the optical disk is controlled at a constant angular velocity by the CAV control means, a reference value is set in a reference value register 32, and an optimal gain is calculated from this reference value and set in a multiplying circuit 35 for setting gain. Since the gain of a servo loop is set to be optimal according to the rotational speed of the disk, always stable servo control is performed irrespective of the high or low speed of the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording and / or reproducing apparatus, and in particular, to an MD (Mini
Disc) The present invention relates to a disc recording and / or reproducing apparatus in which writing / reading of an optical disc is performed intermittently like a recording / reproducing apparatus.

[0002]

2. Description of the Related Art For example, a cartridge having a diameter of 6
2. Description of the Related Art An MD (Mini Disc) recording / reproducing apparatus which compresses and records / reproduces digital audio data on a 4 mm optical disk or a magneto-optical disk has been widely used. M
The D recording / reproducing apparatus compresses and records digital audio data, thereby making it possible to record digital audio data having a recording time comparable to that of a CD (Compact Disc), for example, using an optical disk having a diameter of 64 mm.
MDC is used as a compression method for digital audio data.
ATRAC (Adaptive Transform Aco) that compresses data based on T (Modified Discrete Cosine Transform)
A system called ustic coding is used.

[0003] In an MD recording / reproducing apparatus, at the time of reproduction, recorded data on an optical disk is read out.
After EFM demodulation and error correction processing are performed, they are stored in a buffer memory. Then, the output of the buffer memory is sent to the ATRAC decoder and expanded.

[0004] The transfer rate of a reproduction signal from an optical disc when reproduction is performed by an MD recording / reproducing apparatus is 1.4 Mbi.
The data transfer rate required by the ATRAC decoder is 0.3 Mbit / s, while the rate is t / s. Therefore, the data reproduced from the optical disk is written into the buffer memory at a speed of 1.4 Mbit / s, and is read at a speed of 0.3 Mbit / s. Since the transfer speed of data from the optical disk is faster than the transfer speed of data to the ATRAC decoder, data accumulates in the buffer memory. When a certain amount of data is accumulated in the buffer memory, the reading of data from the optical disk is stopped, and the reading of data from the buffer memory is continued. Then, when the data in the buffer memory becomes smaller than the predetermined amount, reading of data from the optical disk is started again.

As described above, in the MD recording / reproducing apparatus,
Reading data from the optical disk is performed intermittently. During a period in which the buffer memory has a predetermined amount of data or more and data is not being read from the optical disk, data reading from the buffer memory and AT
Only the RAC decoding process is performed. Therefore, when data is read intermittently from the optical disk in this manner, during the period in which the optical disk is not being read, the buffer memory read processing, the ATRAC decode processing, and the reproduction data Is converted into an analog signal, and only the portion of the D / A conversion process of outputting the analog signal needs to be operated.
A laser beam driving circuit, a servo circuit, a demodulation circuit, and the like can be turned off. If the other circuit portions are turned off during a period in which the optical disk is not being read, power consumption can be reduced accordingly.

By the way, data is recorded at a constant linear velocity on an optical disk or a magneto-optical disk of an MD system. When reading data from an optical disk, it is necessary to control the rotation of the disk at a constant linear velocity. Such control is unnecessary when the reading of data is not performed. Therefore, when the optical disk is not being read, the rotation of the optical disk is turned off,
It is conceivable to reduce the power consumption by turning off the spindle servo.

However, if the rotation of the optical disk is stopped while the optical disk is not being read, a large current is required to restart the rotation of the optical disk, and the power consumption is rather increased. When the spindle servo is turned off, the rotation speed of the optical disk during that time becomes unstable, so that the speed difference from the rotation speed when restarting the rotation of the optical disk becomes large. For this reason, a large current is required until the rotation speed of the optical disk is controlled to a predetermined rotation speed, which results in an increase in power consumption.

For this reason, the MD recording / reproducing apparatus intermittently reads the optical disk at the time of reproduction, and holds the optical disk at a constant linear velocity (CLV) at the time of reading the optical disk.
When the optical disk is not read out, the optical disk is controlled at a constant angular velocity (CAV).

Conventionally, the CAV control is configured to compare a cycle of an FG signal from a spindle motor with a reference value and control the spindle motor according to the comparison output. That is, in FIG. 6, the FG signal from the spindle motor is supplied to the input terminal 101. This FG signal is supplied to the FG cycle measurement circuit 102. The FG cycle measuring circuit 102 measures the cycle of the FG signal. This FG
The output of the cycle measurement circuit 102 is supplied to the comparison circuit 103.

In the reference value register 104, a reference value of the rotational speed is set. The output of the reference value register 104 is supplied to the comparison circuit 103. The comparison circuit 103 compares the reference value set in the reference value register 104 with the cycle of the FG signal of the spindle motor.

The output of the comparison circuit 103 is supplied to a low-pass filter 104 and a multiplication circuit 105 for setting a gain.
The multiplication circuit 105 is provided with a loop gain of a predetermined coefficient from an input terminal 106. The output of the multiplication circuit 105 is P
It is supplied to the WM control circuit 107. PWM control circuit 10
7, a PWM signal whose pulse width changes according to the control signal is formed. The output of the PWM control circuit 107 is output from an output terminal 108, and the PWM control circuit 107
Controls the rotation of the spindle motor.

[0012]

As described above, in the MD recording / reproducing apparatus, when the optical disk is driven intermittently and the optical disk is not being read, the laser beam drive circuit, servo circuit, demodulation circuit and the like are turned off. The optical disk is controlled by CAV. A state in which the laser beam drive circuit, servo circuit, demodulation circuit, and the like are turned off and the optical disk is controlled by CAV is called a sleep mode.

In order to prevent power from being consumed by pulling in at the time of switching, when the control of the optical disk is switched from CLV to CAV, the rotation speed of the optical disk is set so that there is no difference in the rotation speed of the optical disk. It is desired.

As described above, in the conventional MD recording / reproducing apparatus, when performing the CAV control, the cycle of the FG signal from the spindle motor is compared with the reference value, and the spindle motor is controlled according to the comparison output. It is configured to control. A multiplication circuit 105 for setting a loop gain is provided in such a CAV servo loop. In a conventional MD recording / reproducing apparatus, the loop gain of the servo loop of the CAV is fixed.

However, when the optical disk is moved from the CLV to the CAV
When the control is switched to the above, if the rotation speed of the disk is set so as not to cause a difference in the rotation speed of the optical disk, the rotation speed of the disk during the CAV control differs depending on the trace position of the pickup. In the conventional MD recording / reproducing apparatus, the loop gain of the CAV servo loop is fixed. However, when the disk rotation speed is different, the servo loop gain can be controlled according to the disk rotation speed. desired.

Accordingly, it is an object of the present invention to provide a disk recording device and a reproducing device capable of appropriately controlling a loop gain according to the rotation speed of an optical disk.

[0017]

SUMMARY OF THE INVENTION The present invention relates to a disk reproducing apparatus for intermittently reading data from an optical disk, a CLV control means for controlling the rotation of the optical disk at a constant linear velocity, and a method for controlling the optical disk at a constant angular velocity. And a switching means for switching between the CLV control means and the CAV control means. When reading an optical disk, the CLV control means controls the optical disk at a constant linear velocity to read the optical disk. When not performed, the optical disk is controlled at a constant angular velocity by the CAV control means, and the CAV is controlled.
This is a disc reproducing apparatus provided with means for setting a loop gain according to the rotation speed of the optical disc when the optical disc is controlled at a constant angular velocity by the V control means.

The gain of the servo loop is optimally set according to the rotational speed of the disk. Therefore, whether the disk is spinning at high or low speed,
Servo control can always be performed stably.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a reproduction-only MD player to which the present invention is applied.

In FIG. 1, reference numeral 1 denotes an optical disk. The optical disc 1 has a diameter of 64 mm housed in a cartridge.
And what is called an MD. In the MD, compressed audio data is recorded at a constant linear velocity, and there are a type that can be recorded and reproduced and a type that is dedicated to reproduction. A recordable / reproducible MD is a magneto-optical disc, and a read-only MD is an optical disc on which data is recorded as a pit string.

The optical disk 1 is driven to rotate by a spindle motor 2. As the spindle motor 2, for example, a brushless motor is used. A spindle control signal is supplied to the spindle motor 2 via a driver 3.

The reading of the optical disk 1 is performed intermittently.
(Constant linear velocity), and when data is not being reproduced, it is rotated at CAV (constant angular velocity). In order to rotate the optical disc 1 at CLV, CLV
A servo circuit 5 is provided. Further, a CAV servo circuit 6 is provided to rotate the optical disc 1 at CAV. The CLV servo circuit 5 has an ADIP (Address In)
Pregroove) output of demodulation circuit 18 or EFM (8-14)
Modulation) and ACIRC (Advanced Cross Interleave Re
The rotation of the optical disc 1 is controlled by the CLV based on the reproduced bit clock from the ed-Solomon Code) circuit 20. C
The AV servo circuit 6 controls the rotation of the optical disc 1 by CAV based on the FG signal output from the spindle motor 2.

The output of the CLV servo circuit 5 is supplied to a terminal 4A of the switch circuit 4. The output of the CAV servo circuit 6 is supplied to a terminal 4B of the switch circuit 4. The switch circuit 4 receives the CLV /
A CAV control signal is provided. The output of the switch circuit 4 is supplied to the spindle motor 2 via the driver 3.

An optical head 8 is provided for the optical disk 1. The optical head 8 has a laser diode for outputting laser light, an optical system such as a polarizing beam splitter and an objective lens, and a plurality of detectors for detecting light reflected from the disk. The optical head 8 has 2
An axis device is provided, and the objective lens in the optical head 8 can be displaced in the focus direction (direction of coming and coming from the disk) and the tracking direction (radial direction of the disk) by the two-axis device. The entire optical head 8 can be moved in the radial direction of the disk by a thread feed motor 9.

Laser light is emitted from a laser diode of the optical head 8, the laser light is reflected by the optical disk 1, and the reflected light is detected by a plurality of detectors of the optical head 8. The output of the laser light from the laser diode is detected by the laser controller 11, and the output of the laser beam is controlled by the laser controller 11.

The output of the optical head 8 is supplied to an RF amplifier 10. The RF amplifier 10 calculates the output of each detector of the optical head 5 to obtain a reproduced RF signal, a tracking error signal, and a focus error signal. Servo processing is performed by these error signals.

That is, the focus error signal obtained by the RF amplifier 10 is supplied to the focus servo circuit 12. A focus control signal is formed from the focus servo circuit 12 based on the focus error signal. This focus control signal is supplied to the biaxial device of the optical head 8 via the driver 13.

The tracking error signal obtained by the RF amplifier 10 is supplied to a tracking servo circuit 14. A tracking control signal is formed from the tracking servo circuit 14 based on the tracking error signal. This tracking control signal is the driver 1
5 is supplied to the biaxial device of the optical head 8.

The tracking error signal obtained by the RF amplifier 10 is supplied to a thread servo circuit 16. The thread control signal is formed from the thread servo circuit 16 based on the tracking error signal. This thread control signal is supplied to the thread feed motor 9 via the driver 17.

When a recordable magneto-optical disc is used as the optical disc 1, the absolute position information is wobble-recorded along the groove of the optical disc.
The output of the RF amplifier 10 is supplied to the ADIP demodulation circuit 18. The ADIP demodulation circuit 18 demodulates the address information recorded on the optical disk 1 by wobbling.

The reproduced RF signal from the RF amplifier 10 is E
It is supplied to the FM and ACIRC decoder 20. EFM
And the ACIRC decoder 20 performs EFM demodulation processing and error correction processing by ACIRC on the reproduced RF signal.

The output of the EFM and ACIRC decoder 20 is temporarily output to the RA under the control of the memory controller 21.
Written to M22. Reading data from optical disk 1 by optical head 8 and RAM from optical head 8
Transfer of reproduction data in the system up to 22 is 1.41M
It is performed at a bit rate of bit / s.

The data written in the RAM 22 is read out at the timing when the transfer of the reproduction data becomes 0.3 Mbit / s, and supplied to the audio compression decoder 23. In the audio compression decoder 23, audio data is expanded by ATRAC.

Writing / reading of data to / from the RAM 22 is performed by the memory controller 21 by specifying an address under the control of a write pointer and a read pointer. As described above, the transfer rate of the reproduction data is 1.41.
Mbit / s, and the write pointer is 1.41 Mbi
It is incremented at the timing of t / s. On the other hand, the read transfer rate is 0.3 Mbit / s, and the read pointer is incremented at a timing of 0.3 Mbit / sec. Data is accumulated in the RAM 22 due to the difference between the write and read bit rates.

When a predetermined amount or more of data is stored in the RAM 22, the increment of the write pointer is stopped, and the operation of reading data from the optical disk 1 by the optical head 8 is also stopped. During this time, the read pointer is continuously incremented.

Only the read operation from the RAM 22 is continued, and when the amount of data stored in the RAM 23 becomes less than a predetermined amount at a certain time, the data read operation by the optical head 8 and the increment of the write pointer are restarted again.
The data is stored in the RAM 22 again.

The output of the audio compression decoder 23 is supplied to a D / A converter 24. The digital audio signal is converted into an analog audio signal by the D / A converter 24. This analog audio signal is output from the output terminal 25.

The overall operation is managed by the system controller 7. An input is provided to the system controller 7 from the input keys 26. The input keys 26 include, for example, a play key, a stop key, an AMS key, and a search key. The output of the system controller 7 is supplied to the display 27. Various settings are displayed on the display 27.

In the MD reproducing apparatus to which the present invention is applied, the reading of data from the optical disk 1 is performed intermittently. When reading data from the optical disk 1, the switch circuit 4 is set to the terminal 4A side,
The rotation of the optical disc 1 is controlled by the CLV. Optical disk 1
If the address is wobble-recorded, the ADI
The output of the P demodulation circuit 18 is supplied to the CLV servo circuit 5. When the address is not wobble-recorded on the optical disc 1, the reproduced bit clock is supplied to the CLV servo circuit 5. In the CLV servo circuit 5, ADIP
Using the output of the demodulation circuit 18 or the reproduced bit clock,
The optical disc 1 is controlled by the CLV.

The reproduction data of the optical disk 1 is demodulated and error-corrected by an EFM and ACIRC circuit 20, supplied to a RAM 22 via a memory controller 21, and stored in the RAM 22. When the capacity of the RAM 22 becomes equal to or larger than a predetermined amount, reading of data from the optical disc 1 is interrupted, and the apparatus enters a sleep mode. In the sleep mode, the operation of the parts other than the memory controller 21, the RAM 22, the audio compression decoder 23, and the D / A converter 24 is stopped in order to reduce power consumption. At the same time, when entering the sleep mode, the switch circuit 4 is set to the terminal 4B side by the CAV / CLV control signal from the system controller 7, and the spindle motor 2
Is controlled by CAV.

FIG. 2 shows an example of the configuration of a CAV servo circuit 6 to which the present invention is applied. In the CAV servo circuit 6 to which the present invention is applied, the sleep mode is set, and when the rotation of the spindle motor 2 is controlled by the CAV, an optimum gain is set according to the rotation speed of the disk.

That is, in FIG. 2, the CAV servo circuit 6 includes an FG cycle measuring circuit 31 for measuring the cycle of the FG signal from the spindle motor 2 and a reference value for setting the FG cycle corresponding to the target rotation speed. A register 32; a comparison circuit 33 for comparing the target value set in the reference value register 32 with the current FG cycle;
And a multiplication circuit 35 for setting a loop gain, and a PWM for forming a PWM signal whose pulse width changes in accordance with the drive signal.
And an M control circuit 36. Further, the CAV servo circuit 6 to which the present invention is applied has a gain setting circuit 37 for setting a gain according to the rotation speed of the disk.

In the sleep mode, the mode is switched to the CAV control, and the switch circuit 4 is switched from the terminal 4A to the terminal 4B.
Side. In the system controller 7, CA
An optimum reference value for V control is obtained, and this reference value is set in the reference value register 22. This reference value is set to a value that minimizes the speed difference from the rotational speed that has been controlled by the CLV until then.

The output of the reference value register 32 is supplied to a gain setting circuit 37. Gain setting circuit 37
Is to set an optimum gain according to the rotation speed of the disk. The rotation speed of the disk is set according to the reference value of the reference value register 32. That is, the gain is set so as to be small when the rotation of the disk is fast at the inner peripheral portion of the disk, to become the outer peripheral portion of the disk, and to increase as the disk rotation becomes slower.

The spindle motor 2 generates an FG signal according to the rotation speed of the spindle motor 2. This FG signal is supplied from the input terminal 30 to the FG cycle measurement circuit 31. The FG cycle measuring circuit 31 measures the cycle of the FG signal. The rotation speed of the spindle motor 2 is detected from the cycle of the FG signal. The output of the FG cycle detection circuit 31 is supplied to the comparison circuit 33.

The comparison circuit 33 is supplied with a cycle for setting the rotation speed of the target disk from the reference value register 32, and the rotation cycle of the spindle motor 2 detected by the FG cycle detection circuit 31 is obtained. Supplied. The comparison circuit 33 compares the value of the reference value register 32 with the current period of the FG signal of the spindle motor 2 to determine a speed error and a phase error. The output of the comparison circuit 33 is supplied to a multiplication circuit 35 via a low-pass filter 34.

The gain is supplied from the gain setting circuit 37 to the multiplication circuit 35. This gain is set according to the rotation speed of the disk, as described above. The multiplication circuit 35 multiplies the output of the low-pass filter 34 by a gain from the gain setting circuit 37 according to the rotation speed of the disk. The output of the multiplication circuit 35 is output from the output terminal 37 via the PWM control circuit 36. The output controls the rotation of the spindle motor 2.

As described above, in the MD reproducing apparatus to which the present invention is applied, the CAV servo control circuit 6 has a gain control circuit 3 for controlling a gain according to the number of rotations of a disk.
7 are provided. Thereby, it is possible to always set the optimum servo gain.

In the above example, the gain during the CAV control is controlled according to the rotation speed of the disk. However, even when the CLV control is performed, the gain is controlled according to the rotation speed. May be controlled.

That is, as shown in FIG. 3, the gain obtained by the gain setting circuit 37 from the output of the reference value register 32 is sent to the CLV control circuit 5. When the sleep mode ends, the mode is changed to the reproduction mode, and the CLV control is performed. At this time, the reference value register 3
The gain in the CLV control is set by the gain according to the rotational speed of the disk obtained by the gain setting circuit 37 from the output of No. 2. By doing so, stable servo control is performed not only at the time of CAV control but also at the time of shifting to CLV control.

In the example shown in FIG. 2, when the system enters the sleep mode and shifts from the CLV control to the CAV control, the optimum reference value for the CAV control by the system controller 7 is obtained from the trace position of the disk. It is set in the register 22. However, if the FG cycle immediately before the shift to the CAV control is used as the reference value, the rotation of the disk can be controlled at substantially the same rotation speed as when the control was performed by the CLV until then. This way,
The process of obtaining the optimum reference value for CAV control by the system controller 7 is not required.

FIG. 4 shows a configuration in which the rotation speed of the disk when the control is shifted to the CAV control in this way is set.

In FIG. 4, an FG signal corresponding to the rotation of the spindle motor 2 is supplied from an input terminal 40, and the FG cycle is measured by an FG cycle measuring circuit 41. When entering the sleep mode, the control is switched from the CLV control to the CAV control. At this time, the switch circuit 4 in FIG. 1 is switched from the terminal 4A side to the terminal 4B side, and the reference value register 42
The terminal 48 receives a CAV command from the terminal 48.

When receiving the CAV command, the reference value register 42 latches the output of the FG cycle measuring circuit 41.
Accordingly, the reference value register 42 latches the FG cycle at the time of CLV control immediately before entering the sleep mode. The output of the reference value register 42 is supplied to the comparison circuit 43.

The output of the reference value register 42 is supplied to a gain setting circuit 47. Gain setting circuit 47
Is to set an optimum gain according to the rotation speed of the disk. The rotation speed of the disk is set according to the reference value of the reference value register 42.

The FG cycle measuring circuit 41 measures the current cycle of the FG signal. The output of the FG cycle detection circuit 41 is supplied to the comparison circuit 43. The comparison circuit 43 compares the value of the reference value register 42 with the current FG value of the spindle motor 2.
The period of the signal is compared to determine the speed error and the phase error. The output of the comparison circuit 43 is a low-pass filter 4
The signal is supplied to the multiplication circuit 45 via the line 4.

The gain is supplied from the gain setting circuit 47 to the multiplication circuit 45. The multiplication circuit 45 multiplies the output of the low-pass filter 44 by a gain from the gain setting circuit 47 according to the rotation speed of the disk. The output of the multiplication circuit 45 is output from the output terminal 47 via the PWM control circuit 46. The output controls the rotation of the spindle motor 2.

In this case as well, as shown in FIG. 3, when the sleep mode ends and the CLV control is performed, the CLV control is performed in accordance with the rotation speed at the time when the disk was rotated by the CAV control. Of course, the gain in the CLV control may be controlled.

In the above example, the reproduction-only MD is used.
Although it is a player, it is needless to say that the present invention can be similarly applied to an MD recorder / player capable of recording / reproducing. FIG.
It shows an example of an MD recorder / player that can be reproduced.

In FIG. 5, an optical disk 51 is an MD, on which compressed audio data is recorded at a constant linear velocity. The MD includes a recordable / reproducible type and a read-only type, and the recordable / reproducible MD is a magneto-optical disk. The optical disk 51 has a spindle motor 5
2 is driven to rotate. As the spindle motor 52, for example, a brushless motor is used. A spindle control signal is supplied to the spindle motor 52 via a driver 53.

The rotation of the optical disk 51 is controlled by CLV when data is written or data is read, and the rotation is controlled by CAV when data is not written or data is not read. Optical disk 51
A CLV servo circuit 55 is provided to rotate the CLV at CLV. Further, a CAV servo circuit 56 is provided to rotate the optical disc 1 at CAV.

The output of the CLV servo circuit 55 is supplied to a terminal 54A of the switch circuit 54. The output of the CAV servo circuit 56 is supplied to a terminal 54B of the switch circuit 54. The switch circuit 54 includes the system controller 5
7 supplies a CLV / CAV control signal. The output of the switch circuit 54 is supplied to the spindle motor 52 via the driver 53.

The optical head 58 is placed on the optical disk 51.
Is provided. The optical head 58 has a laser diode for outputting laser light, an optical system such as a polarizing beam splitter and an objective lens, and a plurality of detectors for detecting light reflected from the disk. Optical head 5
8 is provided with a two-axis device, by which the objective lens in the optical head 58 can be displaced in the focus direction and the tracking direction.

The magnetic head 8 faces the optical head 58.
4 are provided. The magnetic head 84 applies a magnetic field modulated by data to the recordable / reproducible optical disk (magneto-optical disk) 51. Optical head 5
8 and the entire magnetic head 84, the thread motor 59
Thus, the disk can be moved in the radial direction.

The laser diode of the optical head 58 emits laser light. The output of the laser light from the laser diode is detected by the laser controller 61, and the output of the laser beam is controlled by the laser controller 61. The power of the laser light from the laser diode is increased to increase the temperature of the optical disk 1 to the Curie temperature or higher at the time of writing, and reduced at the time of reading.

The output of the optical head 58 is supplied to the RF amplifier 60
Supplied to The output of each detector of the optical head 58 is arithmetically processed by the RF amplifier 60, so that the reproduction RF
A signal, a tracking error signal, and a focus error signal are obtained. Servo processing is performed by these error signals.

That is, the focus error signal obtained by the RF amplifier 60 is supplied to the focus servo circuit 62. A focus control signal is formed from the focus servo circuit 62 based on the focus error signal. This focus control signal is supplied to the biaxial device of the optical head 58 via the driver 63.

The tracking error signal obtained by the RF amplifier 60 is supplied to a tracking servo circuit 64. A tracking control signal is formed from the tracking servo circuit 64 based on the tracking error signal. This tracking control signal is transmitted to the driver 6
5 is supplied to the two-axis device of the optical head 58.

The tracking error signal obtained by the RF amplifier 60 is supplied to a thread servo circuit 66. From the thread servo circuit 66, a thread control signal is formed based on the tracking error signal. This thread control signal is supplied to the thread feed motor 59 via the driver 67.

The overall operation is managed by the system controller 57. The system controller 57 includes:
An input is provided from an input key 76. The input key 76
For example, record key, play key, stop key, AMS key,
It consists of a search key and the like. Also, the system controller 5
7 is supplied to the display 77. Various setting states are displayed on the display 77.

At the time of recording, an analog audio signal is supplied to the input terminal 81. This analog audio signal is supplied to the A / D converter 82. The analog audio signal is digitized by the A / D converter 82 with, for example, a sampling frequency of 44.1 kHz, a quantization bit number of 16 bits, and left and right two channels.

The output of the A / D converter 82 is supplied to an audio compression encoder / decoder 73. The audio compression encoder / decoder 73 compresses audio data by ATRAC. In ATRAC, the input audio data is divided into high-frequency, mid-frequency,
It is divided into three low frequency bands. Then, this audio data is cut out at 512 samples (a time window at a maximum of 11.6 msec) and converted into spectrum data by MDCT. This spectrum data is quantized after being normalized for each coding unit. As a result, the audio data is compressed to about 1/5.

The output of the audio compression encoder / decoder 73 is supplied to the RAM 72 under the control of the memory controller 71.
Is stored once. When a predetermined amount or more of data is stored in the RAM 72, the data is read from the RAM 72,
The output of the RAM 72 is supplied to the EFM and ACIRC encoder / decoder 70.

The EFM and ACIRC encoder / decoder 70 performs ACIRC error correction encoding, and further EFM modulates the recording data. This EF
The outputs of M and ACIRC encoder / decoder 70 are:
The data is supplied to a magnetic head 84 via a driver 83, and data is recorded on the optical disk 51 by a magnetic field modulation method.

At the time of reproduction, the reproduction R from the RF amplifier 60 is
The F signal is supplied to the EFM and ACIRC encoder / decoder 7.
0 is supplied. The EFM and ACIRC encoder / decoder 70 performs EFM demodulation processing and error correction processing by ACIRC on the reproduced RF signal.

The outputs of the EFM and ACIRC encoder / decoder 70 are temporarily written to the RAM 72 under the control of the memory controller 71. Since the transfer rate of reproduced data is 1.41 Mbit / s and the transfer rate of read is 0.3 Mbit / s, data is accumulated in the RAM 22 due to the difference between the bit rates of write and read. When a predetermined amount or more of data is stored in the RAM 72, reading of data from the optical disk 51 is interrupted, and only reading of data is performed. Then, when the amount of data stored in the RAM 72 becomes equal to or less than the predetermined amount, data reading from the optical disk 51 is started again.

The output of the RAM 72 is an audio compression encoder /
The data is supplied to the decoder 73. The audio compression encoder / decoder 73 expands the audio signal. The output of the audio compression encoder / decoder 73 is a D / A converter 7
4 is supplied. The digital audio signal is converted into an analog audio signal by the D / A converter 74. This analog audio signal is output from the output terminal 75.

At the time of recording, the recording data is temporarily stored in the RAM 72 until the data in the RAM 72 reaches a predetermined amount. During that time, no data is written to the optical disk 51. When the amount of data in the RAM 72 reaches a predetermined amount, data writing to the optical disk 51 is performed. In this manner, data recording on the optical disk 51 is performed intermittently.

At the time of reproduction, EFM and AC
The output of the IRC encoder / decoder 70 is
When the data is written to M72 and a predetermined amount or more of data is stored in RAM 72, reading of data from optical disk 51 is interrupted, and only reading of data is performed. Then, when the amount of data stored in the RAM 72 becomes equal to or less than the predetermined amount, data reading from the optical disk 51 is started again. In this way, the reading of data from the optical disk 51 is performed intermittently.

The sleep mode is set while data recording on the optical disk 51 is interrupted during recording and while data reading from the optical disk 51 is interrupted during reproduction. In the sleep mode, the memory controller 7
1, RAM 72, audio compression encoder decoder 73, A
The operation of the parts other than the / D converter 82 and the D / A converter 24 is stopped. At the same time, the optical disk 51
While data is being recorded on the optical disk 51 and data is being read from the optical disk 51, the switch circuit 54 is set to the terminal 54A side, and the optical disk 51 is under CLV control. When entering the sleep mode, the switch circuit 54 is set to the terminal 54B side by the CAV / CLV control signal from the system controller 57, and CAV control is performed.

In the case of the MD recorder / player capable of recording / reproducing, the loop gain of the spindle servo is appropriately set according to the rotation speed of the disk during reproduction, similarly to the case of the MV recorder dedicated to reproduction. by doing,
Stable servo can be performed.

In the case of such an MD recorder / player capable of recording / reproducing, a predetermined amount of data is stored in the RAM 72 at the time of recording, and then the data is written to the optical disk 51 and written to the optical disk. Is intermittently written. At the time of recording, as in the case of reproduction, stable servo can be performed by appropriately setting the loop gain of the spindle servo according to the rotation speed of the disk.

Although the examples of the MD reproducing apparatus and the MD recording / reproducing apparatus have been described above, the present invention can be similarly applied to other devices such as a CD reproducing apparatus having a buffer memory.

[0084]

According to the present invention, when the sleep mode is entered and the disk is controlled by the CAV, the rotation speed of the disk is set to be substantially equal to the rotation speed when the disk was controlled by the CLV immediately before. Is done. Then, the gain of the servo loop is optimally set according to the rotation speed of the disk at this time. When returning to the CLV control, the loop gain at the immediately preceding CAV is used. For this reason,
Servo control can always be performed stably even when the disk is rotating at high speed or low speed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an example of an optical disc reproducing apparatus to which the present invention has been applied.

FIG. 2 is a block diagram used for describing an example of an optical disc reproducing apparatus to which the present invention has been applied.

FIG. 3 is a block diagram used for describing an example of an optical disc reproducing apparatus to which the present invention has been applied.

FIG. 4 is a block diagram used to describe an example of an optical disc reproducing apparatus to which the present invention has been applied.

FIG. 5 is a block diagram of an example of an optical disk recording / reproducing apparatus to which the present invention has been applied.

FIG. 6 is a block diagram of an example of a conventional spindle servo circuit. [Brief description of drawings]

[Explanation of symbols]

1 ... optical disk, 4 ... switch circuit, 5 ...
CLV servo circuit, 6 ... CAV servo circuit, 37
..FG cycle measuring circuit, 32 ... reference value register, 3
3 ... Comparison circuit

Claims (8)

[Claims] 1. A disk reproducing apparatus which intermittently reads data from an optical disk, comprising: CLV control means for controlling the rotation of the optical disk at a constant linear velocity; and CAV control for controlling the rotation of the optical disk at a constant angular velocity. Means, and switching means for switching between the CLV control means and the CAV control means.
When the optical disk is controlled at a constant linear velocity by the V control means and the optical disk is not read,
The CAV control means controls the optical disc at a constant angular velocity, and when the CAV control means controls the optical disc at a constant angular velocity, a means for setting a loop gain according to the rotation speed of the optical disc is provided. Disc playback device. 2. The disk reproducing apparatus according to claim 1, wherein when controlling the optical disk at a constant angular velocity by the CAV control means, a rotation speed of the optical disk is set according to a trace position of the optical disk. 3. When the optical disk is switched from a state in which the optical disk is controlled at a constant linear velocity to a state in which the optical disk is controlled at a constant angular velocity, rotation speed information of the optical disk during rotation at the constant linear velocity is taken in. 2. The disk reproducing apparatus according to claim 1, wherein when controlling the optical disk at a constant angular velocity, the rotational speed of the optical disk is set using the acquired rotational speed information obtained when the optical disk is rotated at a constant linear velocity. 4. A disk reproducing apparatus for intermittently reading data from an optical disk, comprising: CLV control means for controlling the rotation of the optical disk at a constant linear velocity; and CAV control for controlling the rotation of the optical disk at a constant angular velocity. Means, and switching means for switching between the CLV control means and the CAV control means.
When the optical disk is controlled at a constant linear velocity by the V control means and the optical disk is not read,
The CAV control means controls the optical disc at a constant angular velocity, and the CLV control means controls the optical disc at a constant angular velocity, and further comprises means for setting a loop gain according to the rotation speed of the optical disc. Disc playback device. 5. A disk recording apparatus which intermittently writes data to an optical disk, wherein: CLV control means for controlling the rotation of the optical disk at a constant linear velocity; and CAV control for controlling the rotation of the optical disk at a constant angular velocity. Means, and switching means for switching between the CLV control means and the CAV control means.
When the optical disk is controlled at a constant linear velocity by the V control means, and the optical disk is not written,
The CAV control means controls the optical disc at a constant angular velocity, and when the CAV control means controls the optical disc at a constant angular velocity, a means for setting a loop gain according to the rotation speed of the optical disc is provided. Disk recording device. 6. The disk recording apparatus according to claim 5, wherein when controlling said optical disk at a constant angular velocity by said CAV control means, a rotation speed of said optical disk is set according to a trace position of said optical disk. 7. When the optical disk is switched from a state in which the optical disk is controlled at a constant linear velocity to a state in which the optical disk is controlled at a constant angular velocity, rotation speed information of the optical disk when the optical disk is rotated at the constant linear velocity is fetched. 6. The disk recording apparatus according to claim 5, wherein when controlling the optical disk at a constant angular velocity, the rotational speed of the optical disk is set using the acquired rotational speed information obtained when the optical disk is rotated at a constant linear velocity. 8. A disk recording apparatus which intermittently writes data to an optical disk, wherein: CLV control means for controlling the rotation of the optical disk at a constant linear velocity; and CAV control for controlling the rotation of the optical disk at a constant angular velocity. Means, and switching means for switching between the CLV control means and the CAV control means.
When the optical disk is controlled at a constant linear velocity by the V control means, and the optical disk is not written,
The CAV control means controls the optical disc at a constant angular velocity, and the CLV control means controls the optical disc at a constant angular velocity, and further comprises means for setting a loop gain according to the rotation speed of the optical disc. Disk recording device.