JP2002170317A - Disk drive device, and method for calculating linear velocity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily detect accurate linear velocity and to utilize the accurate linear velocity in accessing. SOLUTION: First absolute timing information is read at a prescribed position of a disk-shaped recording medium, track jump of the prescribed number of tracks is subsequently conducted, and second absolute timing information is read just after the track jump. Time from first absolute timing information read start timing to second absolute timing information read start timing is also measured. The reproduction required time of one cycle of a track is calculated in the vicinity of the prescribed position by using the respective first and second absolute timing information and the measured time, and the linear velocity of information recorded on the disk-shaped recording medium is further calculated from the reproduction required time for one track cycle and the value of a disk diameter at a corresponding track position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a CD (COMP
(ACT DISC), etc., while the main information is recorded on a spiral track at a constant linear velocity, and the main information is recorded on a disk-shaped recording medium in which absolute time information is continuously recorded in frame units. The present invention relates to a disk drive device that performs recording and reproduction, and a linear velocity calculation method.

[0002]

2. Description of the Related Art As a so-called CD-format disk, for example, a CD-DA (Compact Disc-Digital Audio) is used.
O), CD-ROM, CD-R (CD-RECORDABLE), CD
-Discs belonging to the so-called CD family, such as RW (CD-REWRITABLE) and CD-TEXT, have been developed.
And it is widespread. In this CD format, a spiral track is formed from the inner side to the outer side, and information is recorded in a track shape at a constant linear velocity. And the linear velocity is set to 1.2 to 1.4 m / s in the standard.

In the case of a CD, TOC information is recorded in a lead-in area on the innermost peripheral side of the disk. In the TOC, information such as a start address of each program (music or the like) is managed in order to manage a program area in which a program such as music is recorded. The position (address) on the disk is shown in the form of minutes / seconds / frames as absolute time information continuous from the beginning of the program area. The absolute time information serving as an address is added to each sub-coding frame.

[0004] In general, a unit of music or the like recorded on a CD is often called a "track". However, in order to distinguish it from a recording track spirally formed on a disk, a "program" is used in this specification. Shall be called. Also, the number of a song or the like is generally called a “track number”, which is called a “program number”.

[0005] When playing back a CD, the playback device first sets the TOC
Read information. Thus, the start address of each program can be grasped. When a certain program is reproduced, an optical head (optical pickup) is made to access the start address of the program which is grasped from the TOC information, and after the access is completed, the main information such as music is read.

[0006]

When a certain position on the disk is accessed, a track jump of the optical head is performed. The number of tracks to be jumped is determined by the number of tracks to be jumped. It can be roughly calculated from the difference between the address (absolute time information) and the address as the access target position. Here, "roughly" means that the range of the linear velocity is defined as described above in a CD as a standard. This is because the speed is different. For example, some disks have a linear velocity of 1.2 m / s, and some disks have a linear velocity of 1.4 m / s. If the linear velocity differs, the amount of data (the number of sub-coding frames) recorded in one round of the track differs. If the linear velocity is constant, the amount of data recorded in one round of the track is constant. Therefore, the number of jump tracks is calculated from the address difference (= the number of sub-coding frames to the target position) to the access target position. Can be calculated. However, since the linear velocity is not constant, the number of jump tracks until reaching the access target position cannot be calculated accurately.

As a result, at the time of access, after a track jump of the number of jump tracks roughly calculated is performed, an address is read out at a landing point, a difference from a target address is calculated, and correction of the number of minute tracks is performed again. In many cases, it was necessary to perform a typical track jump. This leads to a longer access time, and there is a problem that the problem of shortening the access time, that is, the problem of promptly starting reproduction at the time of access cannot be realized.

In order to solve such a problem, it is necessary to accurately determine the linear velocity of the loaded disk. In other words, if the linear velocity can be determined, the number of jump tracks for access can be accurately calculated, so that a quick access operation can be realized. Here, in order to determine the linear velocity, the difference between the absolute time information actually read before and after the track jump and the absolute time at the linear velocity assumed in advance, as disclosed in Japanese Patent Laid-Open No. 50676/1985. A method is known in which the assumed linear velocity is corrected based on the difference between the information and the actual linear velocity. However, in this method, an error may occur due to factors such as a delay in servo performance and data reading time. There is also a method of calculating the linear velocity by detecting the rotational angular velocity of the disk as disclosed in Japanese Patent Publication No. Hei 8-21193. In this case, however, it is necessary to provide an angular velocity detecting device, which complicates the configuration and increases the manufacturing cost. Invite.

[0009]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to make it possible to easily and accurately determine the linear velocity of a disk, thereby shortening the access time.

For this reason, in the present invention, main information is recorded on a spiral track at a constant linear velocity, and the main information is provided in units of frames (for example, sub-coding frames) to which absolute time information is continuously added. As a disk drive device for a recorded disk-shaped recording medium, a head means for reading information from the disk-shaped recording medium, a decoding means for decoding the absolute time information from the information read by the head means, and the head means Access means for executing access to a read position from the disk-shaped recording medium by the track jump of the above, and reproduction means. The reproducing means includes: first absolute time information read at a predetermined position on the disk-shaped recording medium; second absolute time information read immediately after a predetermined number of track jumps from the predetermined position; Using the measured time from the start of reading of the first absolute time information to the start of reading of the second absolute time information, the reproduction time of one round of the track near the predetermined position is calculated. The calculating means may further calculate the linear velocity of the information recorded on the disk-shaped recording medium from the reproduction time required for one round of the track and the value of the diameter of the track position.

In the linear velocity calculating method according to the present invention, a first reading procedure for reading the absolute time information at a predetermined position on the disk-shaped recording medium and a track jump of a predetermined number of tracks immediately after the first reading procedure are performed. A track jump procedure to be performed, a second read procedure for reading absolute time information immediately after the track jump procedure, and a time from a start timing of the first read procedure to a start timing of the second read procedure. Using the measurement procedure, the respective absolute time information read in the first and second read procedures, and the time measured in the measurement procedure, the time required to reproduce one round of the track near the predetermined position using the time measured in the measurement procedure Is calculated, and the linear velocity of the information recorded on the disk-shaped recording medium is calculated from the reproduction time required for one round of the track and the diameter of the track position. And calculation procedure, so that it is performed.

In the case of the present invention as described above, the linear velocity of the disk-shaped recording medium can be accurately and easily determined irrespective of the fluctuation of the required track jump time due to the servo performance. Therefore, at the time of access, the number of jump tracks can be calculated based on an accurate linear velocity.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a disk drive device and a linear velocity calculating method according to the present invention will be described. An example in which the disk drive device of the embodiment is a CD playback device will be described. The description will be made in the following order. 1. 1. Configuration of disk drive device 2. Subcode and TOC Linear velocity judgment operation

1. FIG. 1 shows a configuration of a disk drive device. in this case,
The disc 90 is a CD-DA. CD-R, C
Of course, it is possible to make it possible to reproduce other discs in CD format such as D-RW and CD-ROM.

The disk 90 is loaded on the turntable 7 and is rotated at a constant linear velocity (CLV) by the spindle motor 1 during a reproducing operation. Then, pit data on the disk 90 is read by the optical pickup 1.

In the pickup 1, a laser diode 4 as a laser light source, a photodetector 5 for detecting reflected light, an objective lens 2 as an output end of the laser light,
An optical system (not shown) for irradiating the laser beam to the disk recording surface via the objective lens 2 and guiding the reflected light to the photodetector 5 is formed. A monitor detector 22 that receives a part of the output light from the laser diode 4
Is also provided.

The objective lens 2 is held by a biaxial mechanism 3 so as to be movable in a tracking direction and a focusing direction. The entire pickup 1 can be moved in the disk radial direction by a thread mechanism 8. The laser diode 4 in the pickup 1 is driven to emit laser light by a drive signal (drive current) from a laser driver 18.

The reflected light information from the disk 90 is detected by the photodetector 5, converted into an electric signal corresponding to the amount of received light, and supplied to the RF amplifier 9. The RF amplifier 9 includes a current-voltage conversion circuit, a matrix operation / amplification circuit, and the like corresponding to output currents from a plurality of light receiving elements as the photodetector 5, and generates necessary signals by matrix operation processing. For example, it generates an RF signal as reproduction data, a focus error signal FE for servo control, a tracking error signal TE, and the like. The reproduction RF signal output from the RF amplifier 9 is supplied to a binarization circuit 11, and the focus error signal FE and the tracking error signal TE are supplied to a servo processor 14.

The reproduced RF signal obtained by the RF amplifier 9 is 2
The binarized data is converted into a so-called EFM signal (8-14 modulated signal) by the binarization circuit 11 and supplied to the decoder 12. The decoder 12 performs processing such as EFM demodulation, CIRC error correction, and deinterleaving to obtain reproduction data, for example, digital audio data such as music. The decoder 12 also performs a subcode extraction process on the data read from the disk 90, and supplies the TOC and address information as the subcode (Q data) to the system controller 10. Further, the decoder 12
Generates a reproduction clock synchronized with the EFM signal by PLL processing, and executes the decoding processing based on the reproduction clock. The rotation speed information of the spindle motor 6 is obtained from the reproduction clock, and the reference speed By comparing with the information, the spindle error signal SPE
Can be generated and output.

The reproduced data decoded into digital audio data by the decoder 12 is converted into an analog audio signal by, for example, a D / A converter 13 and output from a terminal 20. For example, the data is output to a part such as a power amplifier or a speaker and reproduced and output. In addition,
Although not shown, an interface means for outputting digital audio data to an external device may of course be provided.

APC circuit (Auto Power Control) 19
Is a circuit unit for controlling the output of the laser so as to be constant irrespective of the temperature while monitoring the laser output power by the output of the monitoring detector 22. The target value of the laser output is given from the system controller 10, and the laser driver 18 is controlled so that the laser output level becomes the target value.

The servo processor 14 includes a focus error signal FE and a tracking error signal TE from the RF amplifier 9 and a spindle error signal S from the decoder 12.
Various servo drive signals of focus, tracking, thread, and spindle are generated from the PE and the like, and the servo operation is executed. That is, a focus drive signal FD and a tracking drive signal TD are generated according to the focus error signal FE and the tracking error signal TE, and supplied to the two-axis driver 16. The two-axis driver 16 drives the focus coil and the tracking coil of the two-axis mechanism 3 in the pickup 1. As a result, a tracking servo loop and a focus servo loop are formed by the pickup 1, the RF amplifier 9, the servo processor 14, the two-axis driver 16, and the two-axis mechanism 3.

In response to a track jump command from the system controller 10, the tracking servo loop is turned off and a jump drive signal is output to the biaxial driver 16 to execute a track jump operation.

The servo processor 14 further sends a spindle error signal S to the spindle motor driver 17.
A spindle drive signal generated according to the PE is supplied. The spindle motor driver 17 applies, for example, a three-phase drive signal to the spindle motor 6 according to the spindle drive signal, and executes the CLV rotation of the spindle motor 6. In addition, the servo processor 14 generates a spindle drive signal in response to a spindle kick / brake control signal from the system controller 10, and causes the spindle motor driver 17 to execute operations such as starting, stopping, accelerating, and decelerating the spindle motor 6.

The servo processor 14 generates a thread drive signal based on, for example, a thread error signal obtained as a low-frequency component of the tracking error signal TE and an access execution control from the system controller 10 and supplies the thread drive signal to the thread driver 15. I do. The thread driver 15 drives the thread mechanism 8 according to a thread drive signal. Although not shown, the thread mechanism 8 includes
A mechanism including a main shaft for holding the pickup 1, a thread motor, a transmission gear, and the like is provided.
, The required sliding movement of the pickup 1 is performed.

The various operations of the servo system and the reproduction system as described above are controlled by a system controller 10 formed by a microcomputer. The system controller 10 performs various processes for executing a reproduction operation, an access operation, and the like based on a user operation from an operation unit (not shown).

2. Subcode and TOC Here, according to FIGS. 6 to 10, the area structure of the disc,
The subcode and TOC data will be described. FIG.
Indicates the area structure of the disk 90. Disc 9
The inner side (lead-in area) of 0 is a TOC recording area AT in which TOC data is recorded. Here, T
OC data is repeatedly recorded.

The disk 90 has a diameter of 120 mm, and the area from 50 mm to a maximum of 116 mm as a diameter position is a program recording area APG in which a program such as music is recorded. And program recording area APG
The outer peripheral side is a so-called lead-out area.

In such an area configuration, the recording tracks are formed spirally continuously from the inner peripheral side to the outer peripheral side. And the start position of the program recording area APG,
That is, the track at the diameter position of 50 mm is used as the starting point of the absolute time information as the physical address.

The TOC and subcode recorded in the lead-in area on the CD format disk are as follows. The minimum unit of data recorded on a CD disk is one frame. One block is composed of 98 frames.

FIG. 7 shows the structure of one frame. 1
The frame is composed of 588 bits. The first 24 bits are used as synchronization data, and the following 14 bits are used as a subcode data area. After that, data and parity are allocated.

One frame is composed of 98 frames, and the subcode data extracted from the 98 frames are collected to form one block of subcode data (subcoding frame) as shown in FIG. ) Is formed. Seventy-five sub-coding frames correspond to one second as a reproduction time.

The sub-coding frame 98 is formed.
First and second frames at the beginning of the frame (frame 98
The subcode data from (n + 1, frame 98n + 2) is a synchronization pattern. Then, from the third frame to the 98th frame (frame 98n + 3 to frame 98)
n + 98), each of which has 96 bits of channel data,
That is, subcode data of P, Q, R, S, T, U, V, W is formed.

Of these, P for managing access, etc.
Channel and Q channel are used. However, the P channel only indicates a pause portion between tracks, and the finer control is performed on the Q channel (Q1 to Q1).
Q96). The 96-bit Q channel data is configured as shown in FIG.

First, the four bits Q1 to Q4 are used as control data, and are used for discrimination of the number of audio channels, emphasis, CD-ROM, and whether or not digital copying is possible.

Next, the four bits Q5 to Q8 are ADR, which indicates the mode of the sub-Q data. Specifically, the mode (sub-Q data content) is expressed by the four bits of ADR as follows. 0000: Mode 0: Basically, sub-Q data is all zero (used in CD-RW) 0001: Mode 1: Normal mode 0010: Mode 2: Indicates the catalog number of the disc 0011: Mode 3 ..ISRC (International St
andard Recording Code) 0100: Mode 4 ... Used for CD-V 0101: Mode 5 ... CD-R, CD-RW, CD
-Used in multi-session systems such as EXTRA

The 72 bits Q9 to Q80 following the ADR are used as sub-Q data, and the remaining Q81 to Q96 are CR bits.
C.

The address (absolute address, relative address) is expressed by the sub-Q data when the mode 1 is indicated by ADR. ADR = mode 1
9 will be described with reference to FIG. 9, and the TOC structure composed of the sub-Q data will be described with reference to FIG. In the lead-in area (TOC recording area AT) of the disc, the sub-Q data recorded there is the TOC information. In other words, Q read from the lead-in area
The sub-Q data of 72 bits of Q9 to Q80 in the channel data has information as shown in FIG. Note that FIG. 9A shows a case where the structure (Q1 to Q96) shown in FIG.
The sub Q data portion (Q9 to Q88) of the bit is shown in detail. The sub-Q data has 8-bit data and expresses TOC information.

In the case of FIG. 9A, first, a program number TNO (often called a "track number" in many cases) is recorded in 8 bits Q9 to Q16.
In the lead-in area, the program number is fixed to “00”. Then POIN with 8 bits of Q17 to Q24
T (point) is marked. Q25-Q32, Q33-
The eight bits Q40 and Q41 to Q48 indicate MIN (minute), SEC (second), and FRAME (frame) as absolute addresses. Q49-Q56 is "00000000
0 ". Furthermore, Q57 to Q64, Q65 to Q7
2, PMIN, PSE with 8 bits for each of Q73 to Q80
C and PFRAME are recorded.
The meaning of EC and PFRAME is determined by the value of POINT.

In the sub-Q data in the lead-in area as shown in FIG. 9A, the point (POINT)
The following information is defined by the value of. First, POI
When the value of NT is set to “01” to “99” by the BCD code (binary-coded decimal code), the POIN
The value of T means the program number, in this case PMI
In N, PSEC, and PFRAME, the program start point (absolute time address) of the program number is recorded as minutes (PMIN), seconds (PSEC), and frames (PFRAME). Also, POINT
Is "A0", the program number of the first program in the program recording area APG is recorded in PMIN, and CD-DA (digital audio), CD-I, CD-ROM (XA specification) is determined by the value of PSEC.
Such specifications are distinguished. Further, when the value of POINT is “A1”, the program recording area A is stored in PMIN.
The program number of the last program of the PG is recorded. When the value of POINT is “A2”, PMIN, P
The start point of the lead-out area is set to the absolute time address (minute (PMIN), second (P
SEC), frame (PFRAME)).

The TOC is composed of the sub-Q data shown in FIG. 9A as described above. For example, in the case of a disc in which six programs (six songs) are recorded in the program recording area APG, such TOC is used. TOC by sub-Q data
Means that data is recorded as shown in FIG.

Because of the TOC, the track numbers TNO are all "00" as shown in the figure. Block NO.
Indicates the number of one unit of sub-Q data read as 98-frame block data (sub-coding frame) as described above. Each TOC data has the same contents written over three blocks. As shown in the drawing, there are provided cases where the POINT is "01" to "06" corresponding to the six programs (music and the like). In each case, PMIN, PSEC, PFRAME
, Start points of the first program # 1 to the sixth program # 6 are shown.

When POINT is "A0", PM
IN indicates “01” as the first program number. The disc is identified by the value of PSEC.

When the value of POINT is "A1", P
The program number of the last program (in this case, “06”) is recorded in MIN. Further, the value of POINT is set to the position of “A2”, and PMIN, PSEC, PFRAME
Indicates the start point of the lead-out area. After block n + 27, the contents of blocks n to n + 26 are repeatedly recorded.

In this example, the number of recorded programs is six and the value of POINT is "A0" or "A".
This only shows the case where blocks “1” and “A2” exist. Actually, the value of POINT is “A3”
Subsequent blocks may be provided, and the number of programs naturally differs depending on the disk. Therefore, TO
One unit as C data is not fixed to 27 blocks as shown in FIG.

In the program recording area APG and the lead-out area in which songs and the like are recorded as the programs # 1 to #n, the sub-Q data recorded therein has the information shown in FIG. 9B. FIG. 9 (b)
8 in the structure (Q1 to Q96) of FIG. 8B in the program recording area APG and the lead-out area.
FIG. 7 shows the 2-bit sub Q data portion (Q9 to Q88) in detail.

In the case of FIG. 9B, first, 8 of Q9 to Q16
The program number TNO is recorded in bits. That is, in each of the programs # 1 to #n, "01" by the BCD code is used.
~ 99. In the lead-out area, the track number is "AA". Then Q
The index (X) is recorded by 8 bits of 17 to Q24. The index is information that can further subdivide each program.

Q25 to Q32, Q33 to Q40, Q41
Each of 8 bits from Q48 to Q48, MIN (minute), SEC (second), FR as elapsed time (relative address) in the program
AME (frame) is shown. Q49-Q56 is "0
000000 ". Q57-Q64, Q65-
8 bits of Q72, Q73 to Q80 are AMIN, AS
EC and AFRAME, which are minutes (AMIN) and seconds (ASE) as absolute addresses (absolute time information).
C), frame (AFRAME). The absolute time information is an address continuously added from the beginning of the program recording area APG to the lead-out area.

3. Linear velocity discriminating operation The disk drive device of this example is designed so that the loaded disk 9
The linear velocity of recording data can be accurately and easily determined for 0 (CD). The operation for determining the linear velocity will be described below.

The operation principle for determining the linear velocity is as follows. As described above, the linear velocity of a CD is 1.2 according to the standard.
Ｍ1.4 m / s.
The track at which the program recording area APG starts is located at a diameter of 50 mm. The track at the position of the diameter 50 mm, that is, one round section of the first track of the program recording area APG has 9.817 subcoding frames when the linear velocity is 1.2 m / s. One cycle of reproduction requires 130.9 ms (50π = 130.9 [ms] × 1.2 [m
/ S]). When the linear velocity is 1.4 m / s, one round of the track has 8.415 subcoding frames, and it takes 112.2 ms to reproduce one round of the track (50π = 11.2 [ms]). × 1.4 [m / s]).

The absolute time information included in the Q channel of the above-described sub-code is obtained by setting the sub-coding frame at the beginning of the program recording area APG (the beginning of the track having a diameter of 50 mm) as 00:00:00, and thereafter toward the outer periphery. .., 00, 00, 01, 02,..., And so on, for each sub-coding frame that continues spirally.

The track pitch of the CD is 1.6 μm.
m, which is very small with respect to the diameter of the disk, so that the circumferences of two adjacent tracks can be considered almost the same. In addition, the difference between the rotational angular velocities when two adjacent tracks are reproduced at a constant linear velocity can be neglected. FIG. 4 schematically shows a part of two adjacent tracks TKa and TKb. From the above, the point P on the two adjacent tracks on the same radius shown in FIG.
By reading the absolute time information T1, T2 of 1, P2,
The reproduction time of the signal recorded on one round of the disc is T2-
It can be obtained from T1. However, in reality two points P
Since the absolute time information T1 and T2 cannot be read out at the same time, and the absolute time information is given in units of sub-coding frames and the absolute time read out in sub-codes is in units of 1/75 seconds, In this example, the following processing is executed.

FIG. 2 shows the processing procedure of the system controller 10 for determining the linear velocity. The linear velocity determining process will be described with reference to the flowchart of FIG. 2 and FIGS.

The tracks TKa and TKb in FIG. 4 include sub-coding frames Frame (n), Frame (n + 1),.
ame (m-2), Frame (m-1), Frame (m), Frame (m + 1)..., but in this example, first, for example, absolutely from the sub-coding frame Frame (n) Read time information. In this case, the track TKa is located in the program recording area AP.
The first track of G, that is, the track at the position of 50 mm in diameter may be set (however, it is not necessary to be the first track). The reason why the sub-coding frame is set to Frame (n) is that the frame is not necessarily the sub-coding frame at the head of the track.

As a processing procedure, first, step F in FIG.
As 100, the system controller 10 instructs the servo processor 14 to move the pickup 3 to the innermost track of the program recording area APG. Then, in step F101, the completion of the movement is monitored. When the movement is completed, in step F102, the system controller 10 starts counting the internal timer, and in step F103, the sub-coding frame Frame (n) included in the innermost track. Is performed. At this time, the subcode is extracted by the decoder 12, and the system controller 10 sends the absolute time information (AMIN, ASE).
C, AFRAME).

Subsequently, in step F104, the system controller 10 causes the pickup 3 to execute a track jump of one track toward the outer periphery. That is, as shown in FIG. 4, a one-track jump TJ to the track TKb is executed from the point of time when the reproduction scanning of the sub-coding frame Frame (n) is completed (point P1). The time required for the track jump operation includes the time required for the pickup 3 to move between tracks, the time required for stabilizing the tracking servo after landing on the target track, and the PLL in the decoder 12.
Time is required until the circuit is locked, and data can be reproduced when these operations are completed. Now, when reaching the point P4 in FIG. 4, these processes are completed,
It is assumed that data can be reproduced on the track TKb. In this case, the absolute time information that can be read by the system controller 10 is the absolute time information of the sub-coding frame Frame (m) starting at the point P3.

The system controller 10 proceeds to step F1.
As 05, the time TINT until the data reading start time of the sub-coding frame Frame (m) is measured. This is the count value of the timer which has started counting in step F102 up to the data reading start time. Therefore,
The time TINT is the elapsed time from the start of reading of the sub-coding frame Frame (n) to the start of reading of the sub-coding frame Frame (m).

Subsequently, in step F106, the decoder 12 reproduces the sub-coding frame Frame (m).
Time information (AMIN, ASE) extracted by
C, AFRAME).

At this point, the system controller 10
The absolute time information of the sub-coding frame Frame (n),
The absolute time information of the sub-coding frame Frame (m),
This means that the elapsed time TINT from the start of reading the sub-coding frame Frame (n) to the start of reading the sub-coding frame Frame (m) has been captured. Therefore, in step F107, the reproduction time Tp required for one round of the track on the disk 90 is calculated from these values. The reproduction time Tp for one round of the track is a reproduction time from the point P1 in FIG. 4 to the point P2 on the same radius. This is based on the absolute time information of the sub-coding frame Frame (n).
Assuming that absolute time information of me (n) and the sub-coding frame Frame (m) is Atime (m), Tp = Atime (m) −Atime (n) −TINT (Equation 1) The meaning of this expression will be described later.

Next, in step F108, the linear velocity is obtained from the reproduction time Tp for one round of the track calculated by the above equation 1 and the diameter of the track. The linear velocity is calculated from the length of one round of the track to the reproduction time Tp required for one round of the track.
Is obtained by dividing As described above, since the innermost diameter of the program recording area APG is 50 mm, the linear velocity recorded on the disk 90 is 50π / (Atime (m) −Atime (n) −TINT) (Equation 2) ).

With the above processing, the system controller 10 can accurately determine the linear velocity of the loaded disk 90. Also, no special device configuration is required for calculating the linear velocity. Further, as shown in FIG. 2, the processing / operation for calculating the linear velocity is very simple. Since the linear velocity can be accurately determined in this way, when the pickup 3 accesses a certain target track, for example, the head position of the program, the system controller 10 sets the absolute address as the current address. Using the time information and the absolute time information as the destination address, the number of jump tracks can be accurately calculated. As a result, the access time can be reduced.

Here, the fact that the reproduction time Tp required for one round of the track can be calculated by the above equation 1 will be described. It is assumed that the time required for moving between tracks, the PLL pull-in time, the time required for processing the subcode, and the like are set to zero. It is also assumed that the sub-coding frame (Frame (n)) in FIG. 4 is the 00:00:00 frame at the beginning of the program recording area APG. Then, the point P1 is set to a sub-coding frame (Frame) in which the absolute time information is 00:00:00.
(n + 1)). It is further assumed that the linear velocity is 1.2 m / s. Then, at point P2, which has moved from point P1 in the outer circumferential direction of one track, the absolute time information is 00.
It is a point on the sub-coding frame (Frame (m-1)) which is set to 10 minutes at 00 minutes. This means that the linear velocity is 1.
At 2 m / s, one track is 9.81 as described above.
Since it is composed of 7 sub-coding frames,
The sub-coding frame starting from the P1 point (“0
This is because it is in the middle of the tenth subcoding frame (“10”) counting from “1”).

In practice, it is impossible to read data from the middle of a subcoding frame.
The eleventh frame (Frame (m)) is the first readable sub-coding frame, and the starting point of the sub-coding frame (Frame (m)) is P3 from point P2 in FIG.
To the point, 1-0.817 = 0.183 frames, that is, 2.44 ms elapses in time. Therefore, the absolute time information 00:00:01 of the sub-coding frame (Frame (n + 1)), the elapsed time to the beginning of the first sub-coding frame of the outer circumference of one track, 2.44 ms, and the first of the outer circumference of one track, By detecting the absolute time information of 00:00:11 and 11 frames of the sub-coding frame, the recording time of one round of the track 13 is obtained.
0.9 ms can be calculated. That is, one frame is 1 /
Since it is 75 seconds, in this case, {(11-1) / 75} × 1000−2.44 = 13
0.9 ms. Note that “× 1000” is for adjusting the units of seconds and m seconds.

However, considering that a track jump is performed from the point P1, the sub-coding frame (Fra
The absolute time information of me (n + 1) cannot be read. When the track jumps from the point P1, it can be considered that the track jump is performed after the absolute time information of the sub-coding frame (Frame (n)) is read.

Therefore, in the case of this example, the timing at which the reading of the absolute time information of the sub-coding frame (Frame (m)) starts from the timing at which the reading of the absolute time information of the sub-coding frame (Frame (n)) starts. Is measured as the above-mentioned time TINT. This time TINT is equal to the above P
2.44ms elapsed time from point 2 to point P3, 1
The time value is obtained by adding the playback time of the sub-coding frame. Therefore, the sub-coding frame (Frame (n))
{(11-0) / 75} × 1000-TINT from the absolute time information 00 minutes 00 seconds 00 frame of the first sub-coding frame on the outer circumference of one track and the absolute time information 00 minutes 00 seconds 11 frames = 130.
It can be calculated as 9 ms. This equation corresponds to the above equation 1, and it is understood that the playback time (recording time) Tp for one round of the track can be calculated by the above equation 1. And
If the reproduction time Tp is 130.9 ms, the linear velocity 1.2 m / s can be calculated from the above equation 2 as 50π / 130.9 ms = 1.2 m / s.

In an actual device, first, the subcode is 9
Since the CRC check is performed after reading the data of the six frames, the extraction of the absolute time information has a delay of about one frame from the reproduced RF signal as shown in FIG. However, this delay time is constant irrespective of the sub-coding frame, and similarly occurs during the reproduction of the sub-coding frame before and after the track jump, so that it can be canceled. In other words, the time measured as the period from the start of the reproduction of the sub-coding frame (Frame (n)) to the start of the reproduction of the sub-coding frame (Frame (m)) as shown in FIG. TINT is the same as the time TINT shown in FIG. 3B as a period during which the system controller 10 starts taking in the absolute time information.

When performing a track jump, as shown in FIG.
M, a tracking servo stabilization time tS, and a PLL lock time tP with the reproduced RF signal are required, and the total is a jump required time tTJ. This jump required time t
The TJ cannot read data recorded on the disk 90. Then, assuming that a track jump is started from the point P1 in FIG.
If the elapsed time up to the point P3, which is the beginning of the first subcoding frame after the track jump, is smaller than 2.44 ms in the above-described example, the reproduction time Tp for one round of the track is obtained by Equation 1 as described above. be able to. This is, for example, as shown in FIG.
4 shows a case where the track TKb can be reproduced. In other words, the sub-coding frame (Frame
This is the case where the absolute time information of (m)) can be read.

However, when the total time of the time required to move between tracks, the PLL pull-in time, etc., as the required jump time tTJ, exceeds the elapsed time from the track jump to the beginning of the first subcoding frame. There is. For example, as shown in FIG.
After the track jump is started from around one point, the track jump, the servo settling, and the PLL lock are completed, and the data can be reproduced in the point P5. In this case, the subcoding frame is already
Since the position is in the middle of (Frame (m)), the absolute time information cannot be read from the sub-coding frame (Frame (m)). In this case, the next sub-coding frame (Frame (m + 1)) is a sub-coding frame from which absolute time information can be read first immediately after the track jump. In such a case, the time TINT from the read start timing of the subcode before the track jump to the read start timing of the subcode after the track jump is required to reproduce one subcoding frame as shown in FIG. This becomes TINT 'which is longer by the required time TFRAME.

At this time, the reproduction time Tp of the signal recorded on one round of the disk is obtained by the following equation (3). That is, the absolute time information of the sub-coding frame Frame (n) is
(N), assuming that the absolute time information of the sub-coding frame Frame (m + 1) is Atime (m + 1), Tp = Atime (m + 1) −Atime (n) −TINT ′ (Equation 3).

Here, since TINT ′ = TINT + TFRAME and Atime (m + 1) = Atime (m) + TFRAME, the time obtained by the above equation (3) is the same as the result of the above equation (1).

The following equation is obtained when a sub-coding frame that can be reproduced first after a track jump is further delayed by a number, for example, because the required jump time tTJ is prolonged. Tp = Atime (m + a) -Atime (n) -TINT "(Equation 4) Here, TINT" is used for reproducing a sub-coding frame a from the time TINT in the expression 1. The required time is longer than the required time TFRAME × a. Therefore, Tp = Atime (m + a) −Atime (n) − (TINT + TFRAME × a) = (Atime (m) + TFRAME × a) −Atime (n) − (TINT + TFRAME × a) = Atime (m) −Atime (n) -TINT. That is, also in this case, the time obtained by Expression 4 is the same as the result of Expression 1 described above.

Therefore, if the absolute time of the sub-coding frame before and after the track jump and the time from the start of the reproduction of the sub-frame data before the track jump to the start of the reproduction of the sub-coding frame data after the track jump are detected, Regardless of the time required for the track jump, the reproduction time Tp for one round of the track can be obtained. In other words, regardless of the cause of the track jump, the servo performance, etc., the reproduction time T
p can be obtained, and as a result, the linear velocity can be accurately determined irrespective of these.

In the above description, one track jump is performed at the time of the linear velocity discrimination processing. However, a plurality of track jumps may be performed. That is, the track pitch of the CD is 1.6 μm, which is very small as compared with the track diameter.
Is within the range of the track whose diameter and the rotational angular velocity at the time of reproduction can be considered to be almost the same, a plurality of (N) tracks are moved, and the disk 1 is calculated by the following equation 5.
The time Tp of the signal recorded in the circumference can be obtained. Tp = Atime (m) −Atime (n) −TINT) / N Equation 5

In this case, the linear velocity is obtained by the following equation (6). 50Nπ / (Atime (m) −Atime (n) −TINT) Expression 6 That is, the linear velocity can be determined in the same manner even when a plurality of track jumps are performed.

Although the embodiment has been described above, the configuration of the disk drive device, the processing example, and the like are not limited to the above example, and various modifications can be considered. FIG. 1 shows an example of a reproducing apparatus as a disk drive apparatus, but the present invention is naturally applicable to a recording apparatus and a recording / reproducing apparatus. Also, a CD-type disk has been described as an example of the disk-shaped recording medium. However, the present invention can be applied to any disk drive device that records data by the CLV method and has a spiral track. For example, the present invention can be applied to a reproducing apparatus and a recording apparatus for a magneto-optical disc / optical disc known as an MD (mini disc).

[0076]

As can be seen from the above description, according to the present invention, the linear velocity of the recording data of the loaded disk-shaped recording medium can be easily and accurately determined. Therefore, when accessing the head position or the like of the target program, the number of jump tracks can be accurately calculated by using the information on the linear velocity that is accurately determined. Therefore, an accurate track jump to a track to be accessed can be performed, and the access time can be shortened. further,
There is no need to arrange special components for determining the linear velocity, and there is an advantage that a high-performance disk drive device can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a flowchart of a linear velocity determination process according to the embodiment.

FIG. 3 is an explanatory diagram of a read signal and a timing at the time of a linear velocity determination operation according to the embodiment.

FIG. 4 is an explanatory diagram of an operation example for determining a linear velocity according to the embodiment;

FIG. 5 is an explanatory diagram of an operation example for determining a linear velocity according to the embodiment;

FIG. 6 is an explanatory diagram of a disk structure.

FIG. 7 is an explanatory diagram of a frame structure of a CD.

FIG. 8 is an explanatory diagram of a sub-coding frame.

FIG. 9 is an explanatory diagram of subcode data.

FIG. 10 is an explanatory diagram of TOC data.

[Explanation of symbols]

1 pickup, 2 objective lens, 2 biaxial mechanism, 4
Laser diode, 5 photo detector, 6 spindle motor, 8 thread mechanism, 9 RF amplifier, 1
0 System controller, 12 decoder, 13 D
/ A converter, 14 servo processors, 90 disks

Claims (3)

[Claims] 1. A disk-shaped recording medium in which main information is recorded on a spiral track at a constant linear velocity and the main information is recorded in frame units to which absolute time information is continuously added. A drive unit for reading information from the disk-shaped recording medium; a decoding unit for decoding the absolute time information from the information read by the head unit; Access means for executing access to the read position; first absolute time information read at a predetermined position on the disc-shaped recording medium; and second absolute time information read immediately after a predetermined number of track jumps from the predetermined position. From the start of reading the first absolute time information and the second absolute time information By using the measurement time to start, the disk drive apparatus characterized by comprising a calculating means for calculating a one track playback time required in the predetermined position near. 2. The method according to claim 1, wherein the calculating means calculates a linear velocity of information recorded on the disk-shaped recording medium from a reproduction time required for one round of the track and a value of a diameter of the track position. Item 2. The disk drive device according to item 1. 3. A disk-shaped recording medium in which main information is recorded on a spiral track at a constant linear velocity, and wherein the main information is continuously recorded in frame units to which absolute time information is added. As a linear velocity calculating method for calculating the linear velocity of the recorded information, a first reading procedure for reading out absolute time information at a predetermined position on a disk-shaped recording medium; A track jump procedure for performing a track jump; a second read procedure for reading absolute time information immediately after the track jump procedure; and a time from a start timing of the first read procedure to a start timing of the second read procedure. Measuring procedure, measuring the absolute time information read in the first and second reading procedures, and the time measured in the measuring procedure Then, the time required for reproduction of one round of the track in the vicinity of the predetermined position is calculated. A linear velocity calculation method, comprising: calculating a linear velocity;