JP2004134006A - Disk playback device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed reproduction disk playback device for prolonging the life of a motor by limiting a rotational speed even when an inexpensive spindle motor is used, and highly resistant to vibration. <P>SOLUTION: A playback driving control device 18a gradually switches a reference clock for data reproduction by a CLV varying device so as to make an angular velocity almost constant from the inner periphery of the disk 1 to the outer periphery thereof in accordance with the address signal of data reproduced from the disk 1 during high-speed reproduction, thereby increasing the reproduction linear velocity of a disk 1. This is accompanied by an increase in the speed of an audio signal input to a shock-proof memory 11. Thus, output audio data from the shock-proof memory 11 is gradually switched by an output pitch varying device 22 so as to prevent the data empty state of the memory, and then reproduced at a high speed. Additionally, the playback driving control device 18a is capable of executing rotary-driving so as to make a linear velocity constant in a region in which an address signal is equal to or higher than a predetermined address during the high-speed reproduction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention uses a reproducing device and a recording device to reproduce an optical disk or a magneto-optical disk on which data is written at a constant linear velocity, such as a compact disk (hereinafter referred to as a CD) and a mini disk (hereinafter referred to as an MD), at a high speed. More particularly, the present invention relates to a disk reproducing apparatus on the reproducing side when recording the reproduced output at high speed, and particularly to a disk reproducing apparatus having a shock proof function at high speed reproduction and resistant to vibration and the like.
[0002]
[Prior art]
Discs such as CDs are generally recorded by a CLV (Constant Linear Velocity) method in which the linear velocity at the time of reading signals is constant in order to increase the recording density. Therefore, in order to ensure a constant linear velocity over the entire recording area of the disk, the disk is rotated at a high speed when reproducing the inner peripheral portion having a small radius, and when reproducing the outer peripheral portion having a large radius. It is necessary to rotate the disk at low speed. For this reason, when changing the signal reading position between the inner peripheral portion and the outer peripheral portion, not only is the reproducing head for reading the recording signal moved in the radial direction of the disk, but also the linear velocity of the read signal with respect to the reproducing head is reduced. It is necessary to change the number of revolutions of the disk so as to be constant (for example, see Patent Document 1). In addition, various types of devices having a shock-proof memory have been proposed in order to prevent sound skipping due to vibration of the device ( For example, see Patent Document 2.)
[0003]
FIG. 3 shows a configuration of a conventional disk reproducing apparatus having both the above-mentioned technologies. Address information (absolute time information from the inner circumference to the outer circumference of the disc) is physically recorded as audio information and subcode information on spirally formed recording tracks on the surface of the CD 1 as an example of the disc. . The disk 1 is placed on a turntable 2 and is held from above by a clamper 3. The turntable 2 is connected to a rotating shaft 5 of a spindle motor 4 and is rotated by the spindle motor 4. The pickup 6 is driven by a traverse motor 7 on a slider 8 in a radial direction of the disk 1 to scan a recording track of the disk 1 and generate a reproduction signal Spu.
[0004]
The servo control device 9 is connected to the output of the pickup 6, amplifies the reproduction signal Spu and outputs it as a reproduction signal SPU, and also performs a focusing control operation for focusing the light beam of the pickup 6 on the signal surface of the disk, as well as an optical control. It performs a tracking control operation for causing the beam to follow a recording track on the signal surface of the disk, and outputs a traverse following signal for performing traverse feed.
[0005]
The decoder 10 generates a data reproduction clock signal from the reproduction signal SPU output from the servo control device 9, performs various signal processing on the reproduction signal SPU based on the data reproduction clock signal, and outputs an audio data signal. And outputs the sub-code information signal included in the reproduction signal SPU to generate a sub-code information signal. The subcode information includes the address information of the disc, and the reproduction is performed based on the address information. Further, the decoder 10 also detects a track jump or out-of-focus based on the reproduction signal SPU.
[0006]
A reproduction drive control device 18 serving as a rotation control means is connected to the decoder 10 and generates a traverse forced feed signal for instructing a traverse movement of the pickup 6, that is, a movement of the disc 1 in a radial direction, based on the subcode information. I do.
[0007]
The traverse motor driver 17 is connected to the servo control device 9 and the reproduction drive control device 18, and generates a traverse motor drive signal based on the traverse follow error signal and the traverse forced feed signal. The traverse motor 7 is connected to a traverse motor driver 17 and moves the pickup 6 in the traverse direction.
[0008]
On the disk 1, data strings are grouped and recorded in one block called a frame, and a pattern called a frame synchronization signal is continuously recorded at a fixed interval at the head of the frame.
[0009]
The synchronization signal detector 13 outputs a frame synchronization signal component necessary for CLV control for rotating the disk at a constant linear speed from among the reproduction signals read from the disk 1 inside the decoder 10 during reproduction.
[0010]
The reference clock generator 14 has a predetermined frequency and outputs a reference clock signal that determines the linear velocity of the disk. Both the frame synchronization signal extracted from the reproduction signal SPU and a preset reference clock signal are input to the CLV error detector 15. The CLV error detector 15 compares the frequencies of the two clock signals, obtains the difference between the clocks, and outputs a CLV error signal. The spindle motor driver 16 is connected to the output of the CLV error detector 15 and generates a spindle motor drive signal for driving the spindle motor 4 based on the CLV error signal. The spindle motor 4 is connected to a spindle motor driver 16 and is driven and controlled by a spindle motor drive signal to rotate the disk 1 at a predetermined linear velocity.
[0011]
By the way, at the time of reproducing a CD, when a large vibration or impact is applied to the disc reproducing apparatus, a track jump or a loss of focus occurs, so that the sound is interrupted or skipped. Such a break or skip can be prevented by providing a shock-proof memory. Generally, the speed at which data is written to the shock-proof memory is set faster than the speed at which data is read, so that data is always stored in the shock-proof memory, and data is read from the disk by large vibrations or the like. Even when data cannot be read, data can be read from the shock proof memory at a constant speed. Output data from the shock proof memory 11 is input to the output interface 12 at a constant speed, is formed into a signal suitable for an externally connected device inside the output interface, and is output from the output terminal 20.
[0012]
Further, a main controller 19 for controlling the entire operation of the disc reproducing apparatus is provided. The main controller 19 is provided with input means for the user to operate the disk reproducing device.
[0013]
FIG. 4 shows the relationship between the input data transfer speed to the shock proof memory and the output data transfer speed during playback in the conventional disk playback device. The horizontal axis indicates the elapsed playback time (absolute time T) of the disk, and the vertical axis indicates the data transfer speed. L3 is a line indicating the transfer speed of the input data to the shockproof memory, and L4 is a line indicating the transfer speed of the output data from the shockproof memory.
[0014]
Hereinafter, the operation of the disk reproducing apparatus thus configured at the time of reproduction will be described. At the time of reproduction, as is well known, the spindle motor 4 is rotated while performing the focusing control operation of focusing the light beam emitted from the pickup on the signal surface of the disk, and the rotation speed of the disk 1 reaches the target rotation speed. Then, a tracking control operation for causing the light beam to follow a recording track recorded on the disk 1 is performed, and a signal reading operation from the disk 1 is started. The pickup 6 reads the signal of the disk 1, extracts a frame synchronization signal necessary for CLV control from the reproduction data generated in the decoder 10 by the synchronization signal detector 13, and outputs the reference clock signal of the reference clock signal by the CLV error detector 15. By comparing the frequency with the frequency and rotating the spindle motor 4 to eliminate the frequency difference, the linear velocity during reproduction is controlled to be constant.
[0015]
The audio data signal demodulated by the decoder 10 is input to the shock proof memory 11 at a constant speed V3, and the audio data signal is output from the shock proof memory 11 at a constant speed V4 lower than the audio data signal input to the shock proof. The amount of data stored in the shockproof memory 11 for output gradually increases. That is, when a shock-proof memory is used, it is necessary to satisfy V3> V4 so that data in the memory is not lost. In addition, since the reproduction linear velocity of the disk 1 is constant, L3 and L4 respectively have constant values V3 and V4 regardless of the disk reproduction position.
[0016]
Since the amount of data stored in the shock proof memory 11 gradually increases due to the above relationship, after the audio data reaches the upper limit of the memory capacity of the shock proof, data reading from the disk 1 is temporarily stopped, and the shock proof memory 11 is stopped. When the memory capacity becomes smaller than a certain value, data reading from the disk 1 is restarted.
[0017]
Further, even when a track jump or an out-of-focus occurs in which the playback position jumps due to vibration or the like during the playback, the playback drive control unit 18 receives the track jump information and the out-of-focus information from the decoder 10 and stores the information in the shock proof memory 11. By returning the optical pickup 6 to the position immediately before the track jump or out of focus until the audio data is exhausted, the audio data signal output from the shock proof memory continues at a constant speed V2 without interruption. The read audio data is input to the output interface 12, formed into a format compatible with the externally connected device, and output from the output terminal 20.
[0018]
[Patent Document 1]
JP-A-07-29299
[Patent Document 2]
JP 05-234347 A
[0019]
[Problems to be solved by the invention]
In such a disk reproducing apparatus, in recent years, it has been permitted to record a music source at high speed to another medium (such as a CD to an MD), and a disk reproducing apparatus capable of high-speed recording has been developed. In order to record at high speed, a disk recorded at a constant linear velocity can be played back at a high linear velocity and at high speed.However, because the linear velocity is constant, the spindle motor must be rotated at a high speed near the inner circumference of the disk. Must.
[0020]
For example, in order to reproduce at 2 × speed, the rotational speed of the disk at the innermost circumference of the disk N = 920 rpm, and at 4 × speed, N = 1840 rpm. Therefore, performance degradation of the spindle motor is considered, and the life of the spindle motor is shortened. Although there is a spindle motor capable of high-speed rotation control, the cost increases.
[0021]
Further, when high-speed rotation is restricted, a frequency signal generator (FG) is provided directly connected to a spindle motor to rotate the vicinity of the inner periphery of the disk at a constant angular velocity and rotate the outer periphery at a constant linear velocity. If the spindle motor is controlled so that the output frequency is constant, the angular velocity can be controlled to be constant. However, the provision of the FG increases the cost and the size of the device.
[0022]
Further, by controlling the rotation of the disk with the angular velocity almost constant, the linear velocity gradually increases, and at the same time, the speed of the input audio data signal to the shockproof memory increases, but the output data signal speed from the shockproof memory remains constant. Therefore, there is a problem that even if the angular velocity is substantially constant and the high speed reproduction is performed, the output data from the shock proof is not accelerated.
[0023]
In order to solve the above problems, the present invention uses an address signal (absolute time signal) of a disk without using a frequency generator, and controls the angular velocity at the inner circumference of the disk to be substantially constant during high-speed reproduction. By gradually increasing the linear velocity and gradually increasing the linear velocity, the audio data input speed to the shock proof memory is increased and the audio data output speed from the shock proof memory is gradually increased, so that the linear velocity is proportional to the reproduction speed. The purpose of the present invention is to provide an inexpensive spindle motor that increases the speed of output data and suppresses high-speed rotation, and that provides a disk reproducing apparatus with improved reliability without loss of sound against vibration and the like. .
[0024]
[Means for Solving the Problems]
In order to solve this problem, an invention of a disk reproducing apparatus according to claim 1 of the present invention comprises a synchronization signal and a reference clock reproduced from an inner circumference to an outer circumference of a disk on which data is recorded at a constant linear velocity. Rotation control means for controlling the rotation of the disc while comparing the signal and signal processing means for decoding a signal reproduced from the disc, demodulating an address signal which is a data signal and time information, and detecting an error state of the reproduced signal; Reference clock switching means for switching a reference clock for data reproduction in accordance with an address signal which is time information of data demodulated by the signal processing means for changing the reproduction linear velocity of the disk; and data demodulated by the signal processing means. A memory means for temporarily storing signals, and a data signal speed outputted from the memory means. Output pitch switching means for switching based on an address signal as recording information, wherein during high-speed reproduction, the rotation control means sets the disk from the inner circumference to the outer circumference so that the angular velocity becomes substantially constant based on the address signal. By controlling the reference clock switching means to gradually switch the reference clock for disc reproduction and controlling the rotation of the disc, the data rate output from the signal processing means is gradually increased to be input to the memory means, The output pitch switching means switches the data signal speed output from the memory means based on the address signal so as to be less than the data signal speed input to the memory means.
[0025]
With this configuration, during high-speed reproduction, the linear clock is gradually increased based on the address signal of the disk so that the frequency of the reference clock is gradually increased. The linear speed increases as the playback moves from the inner circumference to the outer circumference by keeping the rotation speed of the disk almost constant, and the output data speed from the shock proof can be increased accordingly. It has the effect of being able to.
[0026]
According to a second aspect of the present invention, during high-speed reproduction, the rotation control means controls the reference clock switching means so that the angular velocity becomes substantially constant if the address signal is within a predetermined address. A high-speed reproduction is performed by performing a rotation control for gradually switching a clock. At the same time, the output pitch switching means outputs a data signal output from the memory means based on the address signal so as to be less than a data signal speed input to the memory means. The speed is switched so as to gradually increase the speed, and if the address signal is in a region equal to or higher than a predetermined address, the rotation is controlled so that the linear speed becomes constant, and the data signal speed output from the memory means is the data input to the memory means. High-speed reproduction is performed with a constant value less than the signal speed.
[0027]
With such a configuration, if the angular velocity is constant, the linear velocity at the outer periphery of the disk increases, and the frequency of the reproduction signal increases accordingly, so that the disk is reproduced so as to avoid an increase in the operating frequency of the apparatus. It has the effect of being able to.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Parts common to those of the conventional disk reproducing apparatus already described with reference to FIG. 3 are denoted by the same reference numerals, and detailed description is omitted.
[0029]
FIG. 1 is a block diagram of a disk reproducing apparatus according to an embodiment of the present invention, and FIG. 2 shows a relationship between an input data transfer speed and an output data transfer speed to a shockproof memory during high-speed reproduction in the disk reproducing device of the present invention. . In FIG. 2, the horizontal axis indicates the elapsed playback time (absolute time T) of the disk, the vertical axis indicates the data transfer speed, L1 is a line indicating a change in the data transfer speed input to the shock proof memory, and L2 is a shock absorbing line. It is a line showing the output data transfer speed from the proof memory.
[0030]
Disc 1, turntable 2, clamper 3, spindle motor 4, rotating shaft 5, pickup 6, traverse motor 7, slider 8, servo controller 9, decoder 10, synchronization signal detector 13, shock in the disc reproducing apparatus of the present invention. The proof memory 11, the output interface 12, the CLV error detector 15, the spindle motor driver 16, the traverse motor driver 17, the reproduction drive control device 18a, and the main control device 19 are the same as those of the conventional disk reproduction device shown in FIG. It is.
[0031]
However, in the present embodiment, the operation of the reproduction drive control device 18a as the rotation control means is different from that of the conventional example as described below, and the addition of the CLV variable device 21 and the output pitch variable device 22 Is different from the disk reproducing device.
[0032]
The reference clock frequency of the reference clock generator 14 can be varied by the CLV variable unit 21 which is a newly provided reference clock switching means.
[0033]
The CLV variable device 21 is controlled by a reproduction control drive device 18a, and the reproduction drive control device 18a obtains a position of the pickup 6 corresponding to the disk 1 from an address (absolute time) generated based on subcode information at the time of reproduction. Then, a command for changing the reference clock frequency is given to the CLV variable device 21 so that the rotational angular velocity of the disk 1 becomes substantially constant.
[0034]
Further, the reference clock frequency of the reference clock generator 14 operates as a reference clock of an output pitch variable unit 22 which is a newly provided output pitch switching means for switching the speed of output audio data from the shock proof memory. The pitch variable unit 22 switches the speed of audio data output from the shockproof memory according to an address (absolute time) generated based on the subcode information at the time of reproduction.
[0035]
The CLV variable device 21 and the output pitch variable device 22 are composed of, for example, a voltage controlled oscillator (VCO), and the frequency of the reference clock generator 14 is set as a reference and the target frequency and the output frequency are changed according to the control voltage of the reproduction drive control device 18a. Output pitch data may be generated. Alternatively, a high frequency clock may be generated from the reference clock generator 14 and the frequency division ratio may be changed. Alternatively, the reference clock generator 14, the CLV variable device 21, and the output pitch variable device 22 may be integrated so as to generate necessary clock frequency and output pitch data according to a command from the reproduction drive control device 18a.
[0036]
The operation of the disk playback device configured as described above during high-speed playback will be described using a compact disk as an example.
[0037]
First, in order to vary the linear velocity and keep the angular velocity substantially constant during high-speed reproduction, it is necessary to gradually increase the linear velocity as the pickup is moved from the inner periphery to the outer periphery of the disk 1. In order to increase the linear velocity, the clock frequency output from the CLV variable unit 21 may be gradually increased. By increasing the frequency of the reference clock, the clock frequency of the frame synchronization signal detected by the synchronization signal detector 13 becomes lower than the reference clock frequency. That is, the value of the CLV error signal corresponding to the difference between the two clock signals increases. The spindle motor driver 16 drives the spindle motor 4 in the acceleration direction so that the value of the CLV error signal becomes small, and finally, the CLV error signal becomes zero, thereby increasing the linear velocity. .
[0038]
Now, the disk radius position R of the pickup at the absolute time T in the subcode data is as follows: the innermost radius of the disk is Ro, the linear velocity at a constant speed of the disk is Vo (m / s), and the track of the disk is If the pitch ΔR
R = (ΔR · Vo · T / π + Ro ² ) ^1/2 (1)
Is represented by
[0039]
At the time of high-speed reproduction, the permissible maximum angular velocity ωmax must be kept constant from the viewpoint of the performance of the spindle motor.
ωmax = V / R = constant (2)
Is represented by
[0040]
From equations (1) and (2), the linear velocity V at the absolute time T at the maximum angular velocity ωmax during high-speed playback is
V = ωmax · (ΔR · Vo · T / π + Ro ² ) ^1/2 (3)
Is represented by
If the maximum angular velocity ωmax is determined in advance by the equation (3), the linear velocity V of the reproducing disk at the absolute time T can be obtained.
[0041]
For example, if the maximum angular velocity of the spindle motor can be allowed up to twice the innermost angular velocity at a constant speed, the innermost linear velocity is 1.2 m / s (linear velocity at low speed) × 2 = 2.4 m / s. Since s is obtained, ωmax = 96 rad / s from the equation (2), and the linear velocity V with respect to the absolute time T can be obtained from the equation (3). Since the linear velocity V of the disc is the same as the audio data velocity V1 input to the shock proof, the audio data velocity input to the shock proof memory with respect to the absolute time T when the angular velocity is constant is a curve L1 in FIG. Conversely, by changing the reference clock frequency by the CLV variable unit 21 so as to change the audio data speed as shown by the curve L1 as shown in FIG. 2, it is possible to reproduce at a constant angular velocity.
[0042]
As described above, the absolute time is read from the reproduction signal and the frequency of the reference clock is varied by the reference clock variable unit so that the angular velocity during reproduction becomes substantially constant so that the relational expression (3) holds. can do. However, the timing of switching the reference clock by the reference clock variable unit may be changed every time the absolute time changes (13.3 ms of the frame period in the case of 1 × speed), but when the resolution of the reference clock variable unit cannot be obtained. , Every several seconds to several minutes (ΔT1). In this case, the disk rotates at a constant linear velocity during ΔT1.
[0043]
Next, the output pitch variable unit 22 outputs audio data from the shock proof memory so as to have a speed V2 that is lower than the audio data speed V1 input to the shock proof memory by a constant speed, that is, the relationship of V1> V2. Is controlled so that the audio data speed from the shock proof memory is gradually increased while maintaining the above. Alternatively, the output speed of audio data from the shock-proof memory may be adjusted so that the ratio between V1 and V2 is always constant while maintaining the relationship of V1> V2.
[0044]
The timing of gradually increasing the output audio data speed from the shock proof memory may be the same as the timing of switching with the reference clock variable unit, or independently whenever the absolute time changes (13.3 times the frame period of 13.3 ms). The switching may be performed, but if the resolution cannot be obtained, the switching may be performed every several seconds to several minutes (every ΔT2). In this case, the output audio data speed from the shock proof memory becomes constant during ΔT2.
[0045]
Further, if the angular velocity at the time of high-speed reproduction is kept constant to the outermost circumference, the linear velocity in the outer peripheral area increases, the data transfer rate increases in proportion to the linear velocity, and reproduction control cannot be performed due to the restriction of the transfer rate of the system. Therefore, it is necessary to make the linear velocity constant after a certain area being reproduced, as in claim 2. Therefore, if the data transfer speed exceeds a predetermined absolute time at which the data transfer speed reaches an allowable maximum linear speed in advance, the reproduction is performed at a constant linear speed after the predetermined absolute time, and the audio data signal speed output from the shockproof memory 11 is kept constant. By doing so, the data transfer rate in the outermost peripheral area can be kept below the maximum allowable value of the system. For example, in FIG. 2, an absolute time A in which the linear velocity, that is, the audio data velocity input to the shock proof, exceeds the quadruple velocity (linear velocity = 4.8 m / s) is obtained in advance, and the absolute time A during the high-speed reproduction is determined. The output clock data rate from the shock proof memory 11 is gradually increased by the output pitch variable device 22 at the same time until the absolute time exceeds A minutes. The frequency and the audio data signal speed output from the shock proof memory 11 are fixed, and thereafter the disk is rotated at a constant linear speed.
[0046]
As described above, until the linear velocity reaches a certain value, the angular velocity is maintained at a substantially constant value, and consideration is given to the spindle motor. If the angular velocity is exceeded, the linear velocity is kept constant, and the maximum operating frequency on the system is considered.
[0047]
As described above, according to the present embodiment, the linear velocity of the disk is increased from the inner circumference to the outer circumference of the disk, and at the same time, the output audio data rate from the shockproof memory is kept lower than the input audio data rate to the shockproof memory. By increasing the rotation speed, high-speed reproduction can be performed using an inexpensive spindle motor whose rotation speed is limited.
[0048]
In the above embodiment, the maximum linear velocity is set to be four times as high as that at the time of constant-speed reproduction. However, the linear velocity at the time of high-speed reproduction can be freely set as long as the system of the disk reproducing apparatus is within an allowable range.
[0049]
Further, in the embodiment, the case of the audio CD has been described. However, the present invention can be applied to an MD or a magnetic recording medium which is magneto-optical recording, and to a signal form other than an audio signal.
[0050]
Furthermore, the numerical values and the like used in the description of the above-described embodiment are merely examples, and can be changed and implemented as necessary.
[0051]
【The invention's effect】
As described above, according to the disk reproducing apparatus of the present invention, at the time of high-speed reproduction, the rotation control means controls the reference clock switching means so that the angular velocity becomes substantially constant based on the address signal from the inner circumference to the outer circumference. By gradually switching the reference clock for data reproduction and controlling the rotation, the data rate output from the signal processing means is input to the memory means while gradually increasing the data rate, and the output pitch switching means is transmitted to the memory means based on the address signal. By gradually varying the data signal speed output from the memory means so as to be less than the input data signal speed, track jumping and focusing can be performed by vibration, etc. using an inexpensive spindle motor with a limited number of disk rotations. It is possible to enable high-speed playback without interruption of the playback signal even if a deviation occurs. Can, advantageous effect that the life of the spindle motor can also be increased is obtained.
[0052]
Further, at the time of high-speed reproduction, the rotation control means controls the reference clock switching means so that the angular velocity becomes substantially constant if the address signal is within a predetermined address, and performs the rotation control to gradually switch the reference clock, thereby reproducing. If the address signal is in a region equal to or greater than a predetermined address, the rotation is controlled so that the linear velocity becomes constant and the data signal output from the memory means is reproduced at a constant speed, thereby limiting the high-speed reproduction operation frequency on the system. The disk reproducing apparatus described above also has an advantageous effect that data can be reproduced from the innermost circumference to the outermost circumference without exceeding the maximum operating frequency of the system.
[Brief description of the drawings]
FIG. 1 is a block diagram of a disk reproducing apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a relationship between an input data transfer speed and an output data transfer speed to a shock-proof memory during high-speed reproduction according to the embodiment;
FIG. 3 is a block diagram of a conventional disk reproducing apparatus.
FIG. 4 shows an input data to a shockproof memory at the time of reproduction in a conventional disk reproducing apparatus.
Diagram showing the relationship between data transfer speed and output data transfer speed
[Explanation of symbols]
1 disk
2 Turntable
3 Clamper
4 spindle motor
5 Rotation axis
6 Pickup
7 Traverse motor
8 Slider
9 Servo control device
10 Decoder
11 Shock proof memory
12 Output interface
13 Synchronous signal detector
14 Reference clock generator
15 CLV error detector
16 Spindle motor driver
17 Traverse motor driver
18a Reproduction drive control device
19 Main controller
20 output terminals
21 CLV variable device
22 Output pitch variable device

Claims (2)

Rotation control means for controlling the rotation of the disk while comparing a reference signal with a synchronization signal reproduced from the disk from the inner circumference to the outer circumference of the disk where data is recorded at a constant linear velocity;
Signal processing means for decoding a signal reproduced from the disk, demodulating an address signal which is a data signal and time information, and detecting an error state of the reproduced signal;
Reference clock switching means for switching a reference clock for disk reproduction in accordance with the address signal demodulated by the signal processing means for changing the reproduction linear velocity of the disk;
Memory means for temporarily storing the data signal demodulated by the signal processing means,
Output pitch switching means for switching a data signal speed output from the memory means based on an address signal as the time information,
At the time of high-speed reproduction, the rotation control means controls the reference clock switching means so that the disk moves from the inner circumference to the outer circumference so that the angular velocity becomes substantially constant based on the address signal, and gradually switches the reference clock for disk reproduction. By controlling the rotation of the disk, the data signal output from the signal processing means is input to the memory means while gradually increasing the data signal speed. The output pitch switching means is input to the memory means based on the address signal. A disk reproducing apparatus characterized in that a data signal speed outputted from said memory means is varied so as to be less than a data signal speed. At the time of high-speed reproduction, the rotation control means controls the reference clock switching means so that the angular velocity becomes substantially constant if the address signal is within a predetermined address, and performs rotation control for gradually switching the reference clock to perform high-speed reproduction. At the same time, the output pitch switching means switches, based on the address signal, a data signal speed output from the memory means so as to be less than a data signal speed input to the memory means, and outputs an address signal in a region having a predetermined address or more. In this case, the rotation is controlled so that the linear velocity becomes constant, and the data signal speed outputted from the memory means is set to a constant value lower than the data signal speed inputted to the memory means for high-speed reproduction. Item 3. The disk reproducing device according to Item 1.

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