JP3529017B2 - Disk reader - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] [Technical Field of the Invention The present invention provides a disk reader for reading the digital data from the digital disk digital data is recorded on the spiral track, such as CD-ROM It is about. 2. Description of the Related Art Conventionally, a CD-ROM used as a large-capacity data recording medium has a constant linear velocity (CLV: Cons
(Tant Linear Velocity, hereinafter referred to as CLV) A data signal is recorded by a control method. Therefore, when reading the data signal, it may be used CLV control method, when using the CLV control method, seek
The playback position changes as the optical pickup moves as if
In such a case, it is necessary to wait for a data signal reading operation from the current rotational speed of the CD-ROM disk to the rotational speed corresponding to the track at the movement target position . Because of this waiting time, that is access time, read
Ri there is a problem that the start time is delayed. Therefore, in order to solve this problem, a constant angular velocity (CAV: Constant
A reading method using an Angular Velocity (hereinafter, referred to as CAV) control method may be adopted. [0003] When employing the CAV control method [0005] has the rotational speed of the CD-ROM is constant
Therefore, even when the track to be read is changed as in a seek operation, the reading operation of the CD-ROM can be started immediately.
Therefore, the data reading start time can be shortened. However, in the CAV control method, the rotation speed of the CD-ROM is determined according to the speed at which the outermost track of the CD-ROM is read. As a result, the inner peripheral portion door
When reading a rack , the linear velocity of the track becomes slower, which causes a problem that the reading speed is reduced and the data transfer amount is slowed. Generally, the rotation speed of a CD-ROM disk is
Disk rotation such as spindle motor of disk reader
Maximum rotation of the disc as it is limited by the performance of the mechanism
The number is set to the upper limit within a range where the data reading operation is not adversely affected by the vibration of the disk rotating mechanism . The transfer rate of data read from a CD-ROM disk is determined by the digital signal processing circuit (Digital Signal Processor).
Rocessor, less dependent Ri by <br/> the signal processing capability of the called DSP). That is, the reproduction process child DSP signal data
The maximum reproduction speed and the minimum reproduction speed are determined on the basis of the upper limit and the lower limit of the range in which . In order to shorten the access time from the time when the optical pickup in the disk reader is moved from the current position on the digital disk to the target position on the digital disk to start the data reading operation , a disk rotation mechanism , particularly a disk rotation mechanism , is used.
Improved pindle motor performance and DSP processing power
However, there is a problem that the cost is high. [0006] The present invention has been made to solve the conventional problems as described above, the disc rotation
The DSP reproduces and processes the signal data by making full use of the performance of the mechanism and the processing capability of the DSP.
Control the rotation speed of the digital disk based on the maximum playback speed and the minimum playback speed determined from the possible range
Access time can be reduced
The purpose is to provide a disk reading device
is there. [0007] In order to solve the above-mentioned problems, a disk reader according to the present invention comprises a data body along a spiral track and an amount data indicating the data amount of the data body. And a digital signal processing circuit for performing predetermined decoding processing on signal data output from an optical pickup that optically reads the data of the digital disk, and controlling the entire apparatus. Main control unit
And a control value calculation unit that calculates a reading double speed with respect to a standard reading speed when reading the read target data instructed based on the amount data from the main control unit, and a calculation based on an instruction input from the control value calculation unit. A rotation control circuit for controlling the rotation of the disk rotating mechanism so as to attain the rotation speed, wherein the current rotation speed of the digital disk is set to N ₁ , and the movement target position of the digital disk during the seek operation indicated by the amount data is the disk radius r _2, the di
The linear velocity of the digital disc is taken as v, the control value calculation unit, the reproduction in the movement target position in a case where the rotational speed N ₁ is assumed to have moved to the moving target position as it is held to the speed X ₂ (speed ) Is calculated as X ₂ = (2πr ₂ N ₁ ) / 6
0v, and the maximum reproduction speed determined from the signal processing capability of the digital signal processing circuit is Xma.
x (the speed) and the minimum reproducing speed when the Xmin (speed), the playback speed X ₂ that the calculated, Xmin ≦ X ₂ ≦
To determine whether it is within the range of Xmax, if the determination result is within the range, performs a seek operation while maintaining the current state of the rotational speed N ₁ of the digital disc, the determination result range When the moving target position is outside the current position, the rotation speed of the digital disk corresponding to the maximum reproduction speed Xmax of the digital signal processing circuit at the moving target position is calculated in advance. Is smaller than the current position, the rotation speed of the digital disk corresponding to the minimum reproduction speed Xmin of the digital signal processing circuit at the movement target position is calculated in advance, and in any case, the calculated rotation speed has been reached. as well as reading start operation later, so as to continue the read operation in the read range while maintaining constant the number of revolutions It is characterized in that have been made. [0008] According to this disk reading apparatus, a certain number of times
Number of tracks on the digital disk
Can play back data recorded between pockets
Moves to the target position during seek operation using characteristics
If you can play at the current rotation speed even if
CAV that keeps the reading operation while keeping the rotation speed constant
Since the playback is performed by the control method, the rotation speed during seek
The waiting time for acceleration / deceleration time of
Access time can be greatly reduced. Also,
If the current rotation speed needs to be changed during
Changes as much as possible according to the direction of travel from the current position.
Change to a lower rotation speed, and after reaching that rotation speed,
And playback by the CAV control method is executed.
Change in rotation speed can be further reduced.
You. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described.
The state will be described with reference to the drawings. First,
The following describes a digital disk to be used specifically. Figure
1 indicates the recording state of the signal data on the digital disk 1.
FIG. In FIG.
Indicates that signal data is recorded along a spiral track.
Disc, specifically a CD-ROM
I have. A drive shaft is provided at the center of the disk-shaped disk body 108.
A center hole 109 into which 31 is inserted is formed. Ma
According to the standard, the innermost circumference 1 whose radius RS is 25 mm
01 and the inner circumference 102 near the outer circumference of the disk body 108.
Is a data area 105.
ing. The data body that is actually effective is the data in the standard.
The data body is recorded from the innermost circumference 101 side of the data area 105.
A ring shape up to the outermost periphery 106 of the recorded data area
It is recorded only in the data area 106. Also,
In the following description, the track 1 on which signal data is recorded
04 is represented by a disk radius position r. FIG . 2 shows a disk according to an embodiment of the present invention.
FIG. 3 is a block diagram showing an electrical configuration of the reading device. Ingredient
It is physically a CD-ROM reader. Smell
The optical pickup 2 includes a light receiving element for tracking,
Equipped with light receiving element for focus and data reading
On the recording surface of the digital disk 1.
Signal data recorded along a spiral track
Data is read optically and the read signal data is
Output to SP4. The DSP 4 receives the output from the optical pickup 2.
Performs a predetermined decoding process on the signal data
Data obtained by performing load processing
Output to the output unit 6. The DSP is an optical pickup.
Extract the clock component from the data output from step 2,
The extracted clock component is output to the rotation control circuit 7.
You. As the DSP 4, in this embodiment,
The maximum playback speed is the standard reading speed (150 Kbytes / sec)
16x speed and the minimum playback speed is 8 times of the standard reading speed.
A signal capable of reproducing signal data in the double speed range
1 having a signal processing capability. The main control unit 5 includes a CD-ROM reading device.
And the time information is converted to a control value calculation unit.
6 to the control value calculation unit 6 for reading at the time of seeking.
Specify elephant data. The control value calculation unit 6 is the main control unit 5
When the DSP 4 reads the read target data specified by
The reading double speed is calculated. The rotation control circuit 7 starts from the DSP 4
The rotation speed is calculated based on the input clock component, and
Spindle motor 3 based on the rotational speed of
The rotation of the disk 1 is controlled. The amount data indicating the data amount of the data body recorded on the digital disk 1 such as a CD-ROM is recorded as time information. When the digital disk 1 is set at a predetermined position and signal data can be read, various kinds of information are read from the digital disk 1 rotating at a predetermined double speed.
Then, the control value calculation unit 6 determines, based on the time information indicating the data recording time, a necessary control signal from the various information output from the DSP 4, that is, each of the two types specified based on the time information given from the main control unit 2. One of the disk radius r make <br/> issue such speed control signal reading by DSP4 between each. When the digital disk 1 is mounted, the data
When the reading operation of the data is started, the main control unit 5
The calculation unit 6 is provided with time information indicating the data to be read. This
Here, the maximum rotation speed Nmax (rpm) of the digital disk 1
Is determined by the performance of the disk rotation mechanism as described above.
However, in this embodiment, it is 5000 (rpm).
Maximum reproduction speed of data signal by DSP4 (Xmax) (times
Speed) and the minimum playback speed (Xmin) (double speed)
It is determined by the signal processing capabilities, but the form of the implementation
As described above, the maximum playback speed Xmin (times)
Speed) is 16 times faster, and the minimum playback speed Xmin (double speed) is 8 times faster.
It is. FIG. 3 shows a change characteristic of the rotation speed (rpm) of the digital disk when the reproduction speed of the data signal with respect to the disk radius r (unit m) is set to be constant. The change in the number of rotations with respect to the disc radius r when the reproduction speed Xmax is kept constant is shown in FIG.
3a, and the change in the number of rotations with respect to the disk radius r when the signal reproduction speed is kept constant at the minimum reproduction speed Xmin becomes the characteristic curve of FIG. A range of S indicated by oblique lines surrounded by the characteristic curves a and b is a range in which the DSP 4 can read the data signal.
FIG. 3 is a characteristic diagram in the range of the number of rotations equal to or less than the maximum number of rotations Nmax. As described above, the DSP 4 operates at the minimum reproduction speed X
When signal processing is performed on data on the digital disk 1 within a range from min (double speed) to the maximum reproduction speed Xmax (double speed), reproduction processing can be performed without causing a delay in data transfer amount due to a decrease in reading speed. For example, in FIG. 3, DSP 4, the disk radius from the disc radius R ₁ while retaining the digital disc 1 at a constant rotation speed n1
It can be reproduced process without causing a delay in the transfer of data due to a decrease in reading speed signal data until R _2. Also, the signal data on the disk radius R ₂ can be without any trouble signal regeneration if the rotational speed of the range of rotational speed n1 to rotation speed n2. According to the present invention, the characteristics as described above, that is, for example, from a disk radius R ₁ at a constant rotation speed n 1,
Focusing on characteristics of the data can be reproduced between to a radius R _2, and holds the rotational speed constant during the seek operation, CAV control scheme rotational speed of the acceleration and deceleration time of the seek operation by other words To reduce the access time by setting the wait state to zero. That is, when data is read by moving the optical pickup 2 from the current position to the movement target position during the seek operation, conventionally, it takes a considerable time for the rotation speed of the spindle motor 3 to reach the rotation speed corresponding to the movement target position. Therefore, a change in the number of revolutions of the spindle motor 3 during the seek operation is suppressed as much as possible to shorten the access time. [0018] Now, in the above-mentioned disk reader, di
The linear velocity of the digital disk 1 is v (m / S), the current rotational speed of the digital disk 1 is N ₁ (rpm), the disk radius of the target position of the digital disk 1 is r ₂ , the target position of the digital disk 1 the playback speed in the X ₂ (double speed)
Then, the current rotational speed N ₁ (r
pm), the reproduction speed X ₂ (double speed) at the movement target position when it is assumed to have moved to the movement target position is obtained by the control value calculation unit 6 calculating based on the following equation. X ₂ = (2πr ₂ N ₁ ) / 60v Thus, the current rotational speed of the disk
It is assumed that the robot has moved to the target position while maintaining N ₁ (rpm).
The playback speed X ₂ (double speed) at the target position in the case
And the playback speed X ₂ that this calculated, Xmin ≦ X ₂ ≦ X
max, the digital disk 1
While maintaining the current rotational speed N ₁ (rpm) as it is,
Perform a work operation. That is, the seek operation is performed by the CAV control method.
Perform the work. As a result, the waiting time after the seek operation
The playback operation can be started at zero. On the other hand, the calculated reproduction speed X ₂ is equal to Xmi
If it is outside the range of n ≦ X ₂ ≦ Xmax is subsequently moved object position is determined which one of the outer circumferential side or the inner circumferential side with respect to the current position. If it is on the outer circumference side, the control value calculation unit 6 determines the DS at the disk radius r of the movement target position.
The rotation speed of the digital disk 1 corresponding to the maximum reproduction speed Xmax of P4 is calculated in advance. On the other hand, when the movement target position is on the inner peripheral side of the current position, the control value calculating unit 6
Calculates the rotation speed of the digital disk 1 corresponding to the minimum reproduction speed Xmin of the DSP 4 at the disk radius r of the movement target position in advance. In any case, the control value calculation unit 6
Instructs the rotation control circuit 7 to control the rotation of the spindle motor 3 at the calculated rotation speed. From the time when the rotation speed is reached, the rotation speed is kept constant, that is, the light is controlled by the CAV control method. The reading of data from the digital disk 1 by the pickup 2 is started. FIG. 4 is a characteristic diagram specifically showing an access operation based on the technical concept described in FIG. In the figure, a section A corresponds to a half of a disk corresponding to a lapse of time of 0 to 20 minutes when the reproducing operation is started from the innermost track.
The section B is a range of a disc radius r corresponding to a lapse of time of 20 to 40 minutes when the reproducing operation is continued from the innermost track of the section A, and the section C is
This is a range of the disc radius r corresponding to a lapse of time of 40 to 60 minutes when the reproducing operation is continued from the innermost track of the section B. The hatched area and the cross hatched area in each section of A, B, and C indicate the CAV in each section.
This is the range that can be reproduced by the control method. As described above, the control value calculation unit 6 determines which section A, B, or C it is based on the read target data specified by the main control unit 5,
The reading double speed when the sections A to C of the determination result are read by the DSP 4 is calculated. In FIG. 4, the maximum reproduction speed (X
max) = 16 (double speed), minimum reproduction speed (Xmin) = 8 (double speed), maximum number of revolutions 5000 (rpm), linear velocity v of the disk
= 1.3 (m / S). As shown in FIG. 4, for example, when a reading operation is performed while rotating the digital disk 1 at a constant rotation speed by the CAV control method in the section B, the position of the disk radius r in the section A When the seek operation is performed, the rotation speed of the digital disk 1 corresponding to the minimum reproduction speed Xmin in the range indicated by the hatched area A, that is, the rotation number corresponding to the underline surrounding the range indicated by the hatched area A is set. When the rotation speed is reached, the reading operation by the CAV control method for keeping the rotation speed constant is performed. On the other hand, when the reading operation is performed while rotating the digital disk 1 at a constant rotation speed by the CAV control method in the section B, the disk in the section C
When the seek operation is performed at the position of the radius r, the rotation speed of the digital disk 1 corresponding to the maximum reproduction speed Xmax in the range indicated by the hatched area C, ie, the rotation corresponding to the upper line surrounding the hatched area of the section C Is set to a certain number, and when the number of revolutions is reached, C is kept constant at that number of revolutions.
A reading operation is performed according to the AV control method. This allows
The change in the rotational speed can be made as small as possible. As described above, according to the disk reading apparatus of the present invention ,
According to this, a digital display is maintained at a constant rotation speed.
Plays data recorded between a specified number of tracks
By using the characteristics that can be
Even when moving to the target position, playback can be performed at the current rotation speed.
Read operation while maintaining the current speed constant
Is performed by the CAV control method that continues
The waiting time for the acceleration / deceleration time of the rotation speed during seeking is zero.
Access time during seek operation can be significantly reduced
it can. Also, change the current rotation speed during seek operation.
If necessary, correspond to the direction of movement from the current position
Change the rotation speed as small as possible
After the number has been reached, the reproduction by the CAV control method is executed again.
Therefore, this suppresses the change in the number of rotations even smaller.
can do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a data recording state of a digital disk. FIG. 2 is a block diagram showing an electrical configuration of the disk reading device according to one embodiment of the present invention. FIG. 3 shows a case where a data signal reproduction speed is set to be constant.
FIG. 9 is a characteristic diagram showing a change in the number of rotations of the disk with respect to the disk radius . FIG. 4 is an example showing a specific example of an access operation according to the present invention, in a section (A) of time 0 to 20 minutes, time 20 to 40;
FIG. 6 is a characteristic diagram showing ranges that can be reproduced by the CAV control method in a section (B) for a minute and a section (C) for a time of 40/60 minutes. [Description of Signs] 1 Digital disk 101 Innermost circumference of data area 102 Outermost circumference of data area based on standard 103 Outermost circumference of data area where data body is recorded 104 Track 105 on which data to be read is recorded Data area 106 Data area 108 in which data body is recorded Disk body 109 Center hole 2 Optical pickup 3 Spindle motor (disk rotating mechanism) 31 Drive shaft 4 Digital signal processing circuit 5 Main control unit 6 Control value calculation unit 7 Rotation control circuit r Disc radius

Claims (1)

(57) [Claim 1] In a disk reading device for reading data from a digital disk on which a data body and amount data indicating the data amount of the data body are recorded along a spiral track, A digital signal processing circuit that performs predetermined decoding processing on signal data output from an optical pickup that optically reads data on the digital disk; a main control unit that controls the entire apparatus; and the amount data from the main control unit. A control value calculating unit that calculates a double reading speed with respect to a standard reading speed at the time of reading the read target data instructed based on the rotation of the disk rotating mechanism so that the rotation speed becomes a rotation speed calculated based on an instruction input from the control value calculating unit. and a rotation control circuit for controlling the current rotational speed of the digital disc N _1, the amount data Ri r ₂ moving discs radius of the target position of the designated said digital disc during the seek operation is, the de
The linear velocity of Ijitaru disk when the v, the control value calculation unit, the reproduction in the movement target position in a case where the rotational speed N ₁ is assumed to have moved to the moving target position as it is held to the speed X ₂ (speed ) Is calculated as X ₂ = (2πr ₂ N ₁ ) /
60v, and the maximum reproduction speed determined from the signal processing capability of the digital signal processing circuit is X
max (speed) and the minimum reproduction speed when the Xmin (speed), the playback speed X ₂ is that the calculated, Xmin ≦ X ₂
Whether to determine the in the range of ≦ Xmax, if the determination result is within the range, performs the current seek operation while maintaining the state of the rotational speed N ₁ of the digital disc, the determination result is When the moving target position is out of the range and the moving target position is on the outer peripheral side of the current position, the maximum reproduction speed Xmax of the digital signal processing circuit at the moving target position is determined.
The rotation speed of the digital disk corresponding to
On the other hand, when the movement target position is on the inner side of the current position, the rotation speed of the digital disk corresponding to the minimum reproduction speed Xmin of the digital signal processing circuit at the movement target position is calculated in advance, and in any case, the rotation speed is calculated. A disk reading device configured to start a reading operation after the rotation speed is reached, and to continue the reading operation within a reading range while keeping the rotation speed constant .