JPH08180496A - Recording method, reproducing method and reproducing device for magneto-optical disk - Google Patents

Abstract

PURPOSE: To obtain a recording method, a reproducing method and a reproducing device for the optical disk of a sample servo system capable of precisely reproducing the data from a magneto-optical disk in a reproducing system. CONSTITUTION: The magneto-optical disk dividing a pattern detecting a threshold value of an N value to several blocks and recording reference patterns periodically arranged making N pieces a unit in a data area at every sector is made to be a recording medium. The threshold value of the N value is detected from a signal obtained from an optical head optically scanning a track provided on the magneto-optical disk by a threshold value detection part 120A, and the data are detected from the signal obtained by the optical head by a data detection part 120B by using the threshold value of the N value. Thus, the data are reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample servo type magneto-optical disk recording method and reproducing method in which concentric or spiral tracks are divided into a plurality of areas each consisting of a servo area and a data area. And a playback device.

[0002]

2. Description of the Related Art Conventionally, recording / recording of various data is performed by scanning a track formed in a concentric circle shape or a spiral shape with a laser beam.
For optical disc systems that perform playback, the optical disc is rotated and driven at a constant linear velocity (CLV) to record / reproduce data, and the optical disc is rotated at a constant angular velocity (CAV). There is known a CAV system which is driven to record / reproduce data. In addition, there is a continuous servo system that performs tracking control using pregrooves that are continuously provided along the track, and sample servo that performs tracking control using servo areas that are discretely provided on the track. The type is known.

Further, as an optical disk, a recordable RAM disk such as a so-called read-only so-called ROM disk, a write-once disk, a magneto-optical (MO) disk, a ROM area and an R area.
A so-called hybrid disc having an AM area is known.

By the way, in a reproducing apparatus for an optical disc using such a magneto-optical disc as a recording medium, variations in optical system, variations in drive due to variations in circuit constant,
It is known that the amplitude and offset of an MO signal obtained by scanning a track of a magneto-optical disk with an optical head fluctuate due to variations in medium reflectivity and Kerr rotation angle. Therefore, the MO caused by the variation of the drive due to the variation of the above optical system and the variation of the circuit constant.
Variations in the signal amplitude and offset have been removed by adjusting the gain for each drive.

[0005]

By adjusting the gain for each drive as described above, the fluctuations in the amplitude and offset of the MO signal due to the fluctuations in the drive due to the fluctuations in the optical system and the circuit constants can be reduced. If it is removed, an adjustment process for the above-mentioned gain adjustment is required, and not only the equipment for that is required, but also the adjustment work takes time. Further, fluctuations in the amplitude and offset of the MO signal due to variations in medium reflectivity and Kerr rotation angle cannot be removed by performing gain adjustment for each drive in advance. In addition, a relatively long amplitude fluctuation or a sudden amplitude fluctuation may occur due to the influence of the defect of the magneto-optical disk or the adhesion of dust, which makes it impossible to determine the threshold value used for reproducing the data.

In view of the above-mentioned conventional circumstances, an object of the present invention is to record and reproduce a sample servo type magneto-optical disk capable of accurately reproducing data from a magneto-optical disk in a reproducing system. And a reproducing apparatus.

[0007]

SUMMARY OF THE INVENTION The present invention is a recording method for a magneto-optical disk in which concentric or spiral tracks are divided into a plurality of areas each consisting of a servo area and a data area. It is characterized in that a pattern whose threshold value can be detected is divided into several blocks and a reference pattern which is periodically arranged with N units as one unit is recorded together with data in each sector in a data area.

Further, the present invention is a reproducing method of a magneto-optical disk in which a track formed in a concentric circle shape or a spiral shape is divided into a plurality of areas each consisting of a servo area and a data area. A reference pattern in which a detectable pattern is divided into several blocks and arranged periodically with N units as one unit is recorded from the data area for each sector together with data, and an N value is obtained based on a reproduction signal of the reference pattern. Is determined and the data is reproduced.

The reproducing method of the magneto-optical disk according to the present invention is characterized by averaging the values for each block and determining the threshold value of the N value.

Further, in the reproducing method of the magneto-optical disk according to the present invention, a combination of a plurality of average values selected from the one having a smaller difference among all the combinations of _m C ₂ of the averaged values AV _m of each block. Is further averaged to determine the threshold value of the N value.

Further, in the reproducing method of the magneto-optical disk according to the present invention, the threshold value of the N value is determined by further averaging the averaged values excluding the maximum value and the minimum value of each block. Characterize.

Further, in the reproducing method of the magneto-optical disk according to the present invention, the threshold value of the N value is obtained by using the value at the position distant by a predetermined number of samples from the maximum position of the edge existing in the window for the reproduction signal of the reference pattern. It is characterized by determining.

Further, in the reproducing method of the magneto-optical disk according to the present invention, the distribution in each block is examined, and a plurality of values selected from blocks having a small distribution range are averaged to obtain the above N.
It is characterized by determining a threshold value.

Further, in the reproducing method of the magneto-optical disk according to the present invention, when the sampled value of the saturated portion exceeds a certain ratio with respect to the amplitude difference of the edge portion of the reproduced signal of the reference pattern, as a defect, It is characterized in that the threshold value of the N value is determined.

Further, in the reproducing method of the magneto-optical disk according to the present invention, a defect is detected by using the amplitude information sampled when the clock phase is near 0 in the phase detecting pattern of the reference pattern as a threshold, and the N value is Is determined.

Further, according to the present invention, a track formed in a concentric circle shape or a spiral shape is divided into a plurality of areas each consisting of a servo area and a data area, and a pattern capable of detecting a threshold value of N value is divided into several blocks. A reproducing apparatus for a magneto-optical disk in which a reference pattern in which N divisions are periodically arranged as one unit is recorded together with data in the data area for each sector, and a track provided in the magneto-optical disk is optically recorded. Data from the signal obtained by the optical head by using a threshold value detecting means for detecting a threshold value of N value from a signal obtained by an optical head for scanning in a selective manner and a threshold value of N value determined by the threshold detecting means. And a data detecting means for detecting a threshold value of N value based on the reproduction signal of the reference pattern by the threshold detecting means. To determine, characterized by reproducing data.

Further, in the reproducing apparatus for the magneto-optical disk according to the present invention, the threshold value detecting means has an averaging processing means for averaging the values of the respective blocks to determine the threshold value of the N value. To do.

Further, in the reproducing apparatus for a magneto-optical disk according to the present invention, the averaging means selects one having a smaller difference between all combinations of _m C ₂ of the averaged value AV _m of each block. It is characterized in that the threshold of the N value is determined by further averaging the combination of the plurality of average values.

Also, in the magneto-optical disk reproducing apparatus according to the present invention, the averaging processing means further averages the averaged values excluding the maximum value and the minimum value of each block to obtain the N value. Is determined.

Further, in the magneto-optical disk reproducing apparatus according to the present invention, the threshold value detecting means uses a value at a position apart from the maximum position of the edge existing in the window by a predetermined number of samples for the reproduction signal of the reference pattern. It is characterized in that the threshold value of the above N value is determined.

In the reproducing apparatus for a magneto-optical disk according to the present invention, the threshold value detecting means examines the distribution in each block, averages a plurality of values selected from blocks having a small distribution range, and sets the N value. Is determined.

Further, in the reproducing apparatus for a magneto-optical disk according to the present invention, the threshold value detecting means exceeds a certain ratio of the sampled value of the saturated portion with respect to the amplitude difference of the edge portion of the reproduction signal of the reference pattern. In this case, the threshold value of the N value is determined as a defect.

Also, in the magneto-optical disk reproducing apparatus according to the present invention, the threshold value detecting means detects a defect by using the amplitude information sampled when the clock phase is near 0 in the phase detecting pattern of the reference pattern as a threshold value. Then, the threshold value of the N value is determined.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the magneto-optical disk used in the embodiment of the recording method, reproducing method and reproducing apparatus of the magneto-optical disk according to the present invention will be described.

This magneto-optical disk has a zone CAV,
Further, it is an optical disk of the sample servo system, and for example, as shown in FIG. 1, one track is divided into 1400 segments (segment 0 to segment 1399), and the segment is classified into an address segment ASEG and a data segment DSEG. To be done.

On each track of the address segment ASEG, position information in the radial direction on the disc, that is, track number and position information in the tangential direction, that is, segment number, are recorded in advance by pits. That is, pits are formed at the time of making a light disc based on the position information. This address segment ASEG exists every 14 segments, and the track 1
There are 100 laps. Then, as shown in FIG. 7, one frame from one address segment ASEG to the next address segment ASEG is one frame, and one frame is 100 frames per track. 13 segments between two consecutive address segments ASEG become the data segment DSEG. Data segment DSEG is 1 per revolution
There are 300 segments. In addition, each segment has 216
It is composed of areas for servo clocks, and includes servo areas ARs for 24 servo clocks and data areas ARd for 192 servo clocks. In the address segment ASEG, the data area ARd includes an address area ARda and a laser control area ARdb.

The case of the MO disk will be described with reference to FIG. Servo areas ARs include (A) of FIG.
As shown in (E), three pits Pa, Pb, and Pc each having a length of 2 servo clocks are prerecorded with their centers separated by a length of 5 servo clocks. A focus sample area ARfs having a length corresponding to the clock is provided.

As described above, by making the pits Pa, Pb, Pc of the servo area ARs each 2 servo clocks long, the portion where the pits are not formed, that is, the mirror portion is reduced, and the ghost that occurs at the time of disk molding. It is possible to make it difficult to generate pits and the like. Furthermore, at the time of access, RF from pits Pb and Pc
Since the signals are stably reproduced, various servo signals such as tracking servo signals can be stably generated based on the RF signals reproduced from the pits Pb and Pc. Further, by separating the centers of the pits Pa, Pb, Pc by a predetermined distance or more, the pits Pa, Pb
Data interference between RF signals reproduced from b and Pc can be made extremely small. In order to reduce the data interference between the pits, it is desirable that the intervals between the pits Pa, Pb, and Pc be separated by 5 servo clocks or more.

The second pit Pb located in the 11 to 12 clock period and the third pit Pc located in the 16 to 17 clock period are respectively displaced from the track center by ± 1/4 track in the radial direction of the disk. Wobble pits placed at the positions, and these pits Pb,
The tracking error information is given by the difference in the amplitude value of the RF signal reproduced from Pc. As will be described later with reference to FIG. 12, the phase information of the servo clock is given by the difference between the amplitude values of both shoulder portions of the RF signals reproduced from these pits Pb and Pc, and this phase information is added. By doing so, clock phase information independent of the tracking state is given.

The first pit Pa at the beginning of the servo area ARs, depending on its position, is an address mark ADM indicating that the segment is the address segment ASEG, and that the segment is the first segment of the sector. It is classified into a first sector mark STM1, a second sector mark STM2 indicating that the next segment is the first segment of a sector, and a segment mark SGM that does not correspond to any of the above.

When the first pit Pa is located in the 3-4 clock period as shown in FIG. 2 (C), it is in the address mark ADM and in the 4-5 clock period as shown in FIG. 2 (D). When located, the first sector mark STM1,
As shown in (E) of FIG. 2, the second sector mark STM2 is formed when it is located in the period of 5 to 6 clocks. The start position of each sector is shown in FIG. The first pit Pa
The information indicated by can be identified by examining the position where the reproduced RF signal takes the maximum amplitude value by the maximum difference detection, that is, the so-called differential detection method, as shown in FIG.

In this way, the address mark ADM or the first pit Pa is formed by the first pit Pa at the beginning of the servo area ARs.
Sector mark STM1 and second sector mark STM
Since the information indicating 2 is given, it is not necessary to record the sector number or track address in sector units.

In the address segment ASEG,
As shown in FIG. 4, 16-bit track addresses [AM], [A] are used as position information in the radial direction of the disc.
2], [A3], [AL] and its parity [P] and the access code ACC, and frame addresses [FM], [F] as position information in the tangential direction.
The frame code FRC composed of L] is gray-coded and recorded in advance in pits.

In the access code ACC, a 16-bit track address is divided into 4 bits, and the access code ACC shown in FIG.
Table conversion based on the gray code table shown in
From M = 15 to 12 bits (MSN) to A2 = 11 to 8 bits (2SN), A3 = 7 to 4 bits (3SN), AL
= 3 to 0 bits (LSN) in this order. At this time, only when the least significant bit of the 4 bits is "1", the value obtained by taking the 1's complement of the next 4 bits is used. This allows
These access codes change only one pattern between adjacent tracks. The parity code is divided into groups according to the bit position of the access code, and each group [15, 11, 7, 3], [1
4, 10, 6, 2], [13, 9, 5, 1], [12,
In 8, 4, 0], the result of taking the parity which becomes 1 when the number of bits having a value of “1” is an even number is recorded.

As described above, only when the least significant bit of the 4 bits is "1", these access codes change only one pattern between adjacent tracks as a value obtained by taking the complement of 1 for the next 4 bits. By avoiding this, in the case where the pit representing the upper 2-bit gray code and the pit representing the lower 2-bit gray code are the shortest distance "0" with respect to the central one-clock area, In the case of "F" in which is the shortest distance and the other is the longest distance, the central 1-clock area pit is formed, so that the central 1-clock area is continuous with the mirror portion in the radial direction. Not only that, it is possible to make the resin flow uniform during the molding of the disk and enable the molding of a high quality disk.

Here, the access code AC is shown in FIG.
A part of C is shown.

In the frame code FRC, the 8-bit frame address representing the information in the tangential direction of the address segment ASEG, that is, the frame number is divided into upper and lower 4 bits, and the upper 4 bits FM.
= 7 to 4 bits (MSN) and lower 4 bits LM = 3 to 0
The bit (MSN) is gray-coded and recorded in the same manner as the above access code. This frame code can record information of 8 bits, but in reality, its value exists only up to the number 0 to 99 of the address segment ASEG.

The focus sample area ARfs of the servo area ARs is a portion serving as a mirror portion, and in the optical disk drive, focus servo and read power APC (Automatic Power).
er Control), RF signal clamping, etc. It is difficult to accurately specify the positions of various sample pulses for these processes, and fluctuations of ± 0.5 servo clock pitch or less are expected. Therefore, even if this fluctuation is added, the level of the RF signal is modulated by the pits. The mirror section has a region for 6 clocks as a space for sampling with an accurate value without being affected by.

The data area ARd of the data segment DSEG is, as shown in FIG. 6, a data area ARd for 176 to 368 data clocks for recording user data and a prewrite area AR for 12 data clocks.
Consisting of _PR and 4 data clocks of the post-write area AR _PO. The number of data clocks changes depending on the zone. The above-mentioned pre-write area AR _PR secures a distance necessary for preheating until the disc reaches a stable temperature for data recording after the drive starts to irradiate the laser when the disc is an MO disc, and at the time of reproduction. It is provided for use as a clamp area that suppresses DC fluctuation due to signal birefringence. Further, the post-write area AR _PO is provided in order to eliminate the unerased portion of the recorded data during overwriting and to secure a distance for avoiding the data interference caused by the edge of the groove Gr provided on the MO disk. Has been. This magneto-optical disk is bulk erased in one direction at the time of shipment. And, for the pre-write area AR _PR, by recording the same polarity data and bulk erasing direction, it is recorded without data to the pre-write area AR _PR is normally recorded by residual heat shortage of media Since the existing data does not change, a stable signal can be reproduced. Also, by recording the same data for four data clocks in the post-write area _ARPO , it is effective to have a stable data string at a constant value for decoding from the subsequent data in Viterbi decoding. is there.

Here, in a recordable optical disk such as a magneto-optical disk, the area for rewriting data is
Since the pits are not formed in advance, the area serving as the mirror portion is wider than the read-only optical disc in which both data and pits are formed in advance as pits. Therefore, as shown in FIG. 6, by providing the groove Gr in the portion corresponding to the data area ARd, it is possible to reduce the mirror portion and reduce the adverse influence on the servo pit in forming the disk. Since the groove Gr is not used for tracking control, accuracy such as depth thereof is not required. In this embodiment, the wavelength of the laser is λ, and λ
The depth is / 8. Further, one data sector has the reference data 6 as shown in FIG. 7 and FIG.
6 bytes and 2048 bytes of user data (D0 to D2
047), ECC 256 bytes (E1,1 to E16,1
6), CRC 8 bytes (CRC1 to CRC8), and user defined data 40 bytes (UD) for a total of 2418
It consists of bytes. FIG. 8 shows a data format of 2352 bytes excluding the 66 bytes of the reference data.

As the reference data, as shown in FIG. 9, the waveform of the reproduced RF signal is 8T for 4 bytes.
A 66-byte specific pattern, which is composed of a pattern and 12-byte 2T pattern as one block, and four blocks, and a 2-byte all-0 pattern as a margin for setting the detected information, is recorded. . The 8T pattern is a ternary level (high H) in data detection by partial response (1, 1) and Viterbi decoding.
• Medium M / Low L) setting, and the 2T pattern is used to correct DC-like pit position shifts due to recording power fluctuations, etc. during reproduction.

In the data area ARd of the data segment DSEG, the data other than the 66 bytes of the reference data is scrambled. Furthermore, the scrambled data is NRZI converted and recorded for each segment.

A recording / reproducing apparatus using a magneto-optical disk of such a format as a recording medium is composed of a control circuit block 100 and a disk drive 200 as shown in FIG. 11, for example. The basic structure of the recording / reproducing apparatus shown in FIG. 11 is the same as that shown in Japanese Patent Application No. 5-24542. In this recording / reproducing apparatus, commands and data are exchanged with the host computer 300 connected via the SCSI interface.

The processing for transmitting and receiving the above command and data is performed by the controller 101 of the control circuit block 100. The controller 101 adds a CRC, an error correction code, etc. to the data from the host computer 300 at the time of recording, and adds the data to the disk drive 200.
Further, at the time of reproduction, the data from the disk drive 200 is error-corrected and the user data portion is transferred to the host computer 300. Further, commands to the servo system and each block of the disk drive 200 are performed by a digital signal processing circuit (DSP) 102 that performs necessary processing for commands from the controller 101.

In this recording / reproducing apparatus, the DSP 10
2 is the optical disk 2 when the optical disk 201 is mounted on the spindle motor 203 by the loading mechanism 202 in response to a request from the host computer 300 or when the automatic spin-up mode is set.
When 01 is loaded, the spindle motor 204 is sent to the spindle driver 204 via the I / O block 103.
Instruct to rotate 03. Then, the spindle driver 204 outputs a spindle on / off signal SPD when the spindle motor 203 reaches a predetermined rotation speed, and notifies the DSP 102 that the rotation is stable. Further, during this period, the DSP 102 causes the pickup driver 1 to pass through the pulse width modulation (PWM) circuit 104.
The pickup 205 is moved by 05 until it comes into contact with the stopper near the outer peripheral edge or the inner peripheral edge of the optical disc 201, and the beam spot is positioned in the recording area, that is, the inner peripheral area or the outer peripheral area outside the zone. When the focus is pulled in the recording area, data may be erased by mistake in the case of a magneto-optical disk with high sensitivity, but outside the recording area, for example, the above-mentioned inner circumference side area or outer circumference side area, etc. By erroneously erasing the data, the focus is drawn in the area where the data is formed in the pit.

Here, the DSP 102 determines whether the optical disk 201 is a read-only optical disk or a recordable magneto-optical disk based on the media information reproduced from the inner peripheral area or the outer peripheral area. be able to. Since the medium information gray-coded in the same format as the address information is recorded in the inner area or the outer area, the address information and the media information can be read and discriminated by the same method. Moreover, since the gray-coded media information is recorded on a plurality of tracks in the inner circumference area or the outer circumference area, the media information can be reliably read even if the position control of the beam spot is incorrect. .

When the spindle motor 203 rotates at a constant speed and the pickup 205 moves, for example, near the outer peripheral end,
The DSP 102 includes a laser diode 207 provided in a pickup 205 with respect to a laser driver 206 via an I / O block 106 and a D / A converter 107.
Set the bias current LDB of the laser diode 20
A command is issued to the servo-system timing generator (STG) 108 that controls the ON / OFF of the No. 7 so that the laser is emitted. The bias current LDB has a high level during recording and has a low level during reproduction. When laser light is emitted from the laser diode 207, laser light enters the photodetector 208 provided in the pickup 205, and the detection output by the photodetector 208 is passed through the current / voltage (IV) conversion & matrix amplifier 209. And is input to the multiplexer 109 as a front APC signal F-APC converted into a voltage by the IV conversion block.

This front APC signal F-APC is digitized by the A / D converter 110 as a signal which is time-divisionally selected by the multiplexer 109 and is I / O.
It is input to the DSP 102 via the block 111. D
SP102 is a digitized front APC signal F
-APC recognizes the light quantity of the laser light and changes the bias current LDB based on the light quantity control data calculated by the built-in digital filter, thereby controlling the light quantity emitted from the laser diode 207 to be constant. .

Next, the DSP 102 has the PWM circuit 104.
By passing a current from the above to the focus driver of the pickup driver 105, the focus actuator of the pickup 205 is driven up and down to enter the focus search state. At this time, the laser light reflected from the magneto-optical disk 201 is detected by the photodetector 208, and the detection output by this photodetector 208 is I-.
The voltage is converted into a voltage by the IV conversion block of the V conversion & matrix amplifier 209 and is input to the multiplexer 109 as the focus error signal FE via the matrix amplifier.

The focus error signal FE is the same as the front APC signal F-APC in the multiplexer 10.
A signal selected in time division by 9 is digitized by the A / D converter 110 and input to the DSP 102 via the I / O block 111. The DSP 102 returns the focus control data obtained by digitally filtering the digitized focus error signal FE from the PWM circuit 104 to the focus driver of the pickup driver 105,
Configure a servo loop for focus control. RF When focus control is stabilized from the detection output by the photodetector 208 from above the pre-write area AR _PR obtained by I-V conversion and matrix amplifier 209
The amplitude of the signal (for the ROM disk) or the MO signal (for the data area of the MO disk) becomes constant to some extent, and after being clamped to an appropriate potential by the selector & clamp 112, the A / D converter 113 performs A / D conversion. To be converted. By performing clamping using the pre-write area AR _PR, obtained stable signal, it is possible to perform an accurate clamping operation.

The A / D converter 113 generates a servo system clock (SPL) via a clock selector 115.
L) The servo clock signal SCK from the circuit 114 and the data clock signal DCK from the data clock generation (DPLL) circuit 117 are selectively supplied. The clock selector 115 outputs the servo clock signal SCK to the reproduction RF signal from the servo area.
Is selected and the data clock signal DCK is selected for the reproduction RF signal from the data area, which is controlled by the servo system timing generator (STG) 108.

The clock during the servo pull-in operation has the frequency of the free running state of the servo system clock generation (SPLL) circuit 114. The timing pulse for clamping is also the servo clock signal SC of this free-run frequency.
A signal obtained by dividing K by a predetermined value is used.

The SPLL circuit 114 includes the A / D converter 11
The pattern of pits is checked by looking at the amplitude difference of the RF signal digitized by 3, and the same pattern as the pit row in the predetermined servo area is searched. Then, when a pattern is found, a window is opened at the timing when the next pattern should appear, that is, in the servo area of the next frame, and it is confirmed again whether the patterns match. If this operation is continuously confirmed a certain number of times, SPL
It is considered that the phase of the servo clock SCK generated by the L circuit 114 is locked to the rotation phase of the optical disc. Here, as shown in FIG. 12, for example, one servo clock is separated from the center point of the reproduced RF signal waveform with respect to the wobble pit Pb sampled at each timing t _b1 , t _b2 , t _c1 , t _c2 of the servo clock SCK. From the sampling data b1 and b2 at the sampling points on both shoulders and the sampling data b1 and b2 at the sampling points on both shoulders that are one servo clock before and after the center point of the reproduced RF signal waveform for the wobble pit Pc, the phase error data = [(b2 -B1) + (c2-c1)]
The phase error between the servo clock SCK and the servo data can be detected by the calculation of / 2. in this way,
The phase information is wobble pits Pb and Pc in the servo area.
It is obtained by taking the amplitude difference between both shoulders. Furthermore, by adding the phase information obtained from both of the two wobble pits, the gain fluctuation caused by the amplitude change due to the tracking position is absorbed.

When the SPLL circuit 114 is locked, the optical disc reproducing apparatus can recognize the scanning position of the pickup 205 in segment units, and thus can also recognize the position of the first pit Pa, and the four positions A shown in FIG. , B, C, D are opened, and the position having the maximum amplitude is searched for among the RF signals sampled at these four positions A, B, C, D. When the result is position A, it is the address mark ADM, and it can be recognized that this segment is the address segment and the beginning of the frame. Therefore, the built-in frame counter (not shown) is cleared to perform frame synchronization. Can be taken. Since one frame is composed of 14 segments, a window is opened every 14 segments and when the address marks can be continuously recognized, it is judged that the frame synchronization is locked.

Since the position where the address is recorded can be recognized when the frame synchronization is applied, the address decoder (A
The DEC) 116 decodes the access code ACC and the frame code FRC. This ADEC116
Then, the 4-bit gray-coded pattern is decoded by checking the coincidence with the gray code table shown in FIG. Here, the above-mentioned ADEC1
16, the reproduction R at each position a, b, c, d shown in FIG.
The F signal is sampled, and the position where the amplitude value is maximum is determined by the maximum difference detection method (differential detection method). Similarly, the reproduced RF signals at the positions e, f, g, and h shown in FIG. 4 are sampled, the position where the amplitude value is maximized is obtained, and decoding is performed by the combination of these and the gray code table. The track address [AM] to [AL], parity [P], frame address [FM], [FL] are decoded by the above method, and the decoding result is stored in the register. DSP10
2 can detect the current position of the pickup 205 by reading the decoding result stored in this register when these data are confirmed. However,
Since it is gray-coded not only in 4 bits but in the whole, we do not simply look for a match, but compare it with a table that is inverted or non-inverted depending on whether the LSB of the upper 4 bits is "1" or "0". To do. Here, the first decoded frame code FRC is loaded into the frame counter, the numerical value obtained by incrementing this frame counter for each frame is compared with the actual reproduced frame code FRC, and they are successively matched. When it is confirmed that the rotation is synchronized. After this, the numerical value obtained by the frame counter is set to the frame code FRC.
As a result, the frame position is not erroneously recognized even if there are some defects or the like.

Further, the DSP 102 calculates the moving speed of the pickup 205 while reading the gray-coded track address at the time of seek, and the PWM circuit 1
The pickup 205 is moved to a target track by controlling the slide motor of the pickup 205 from 04 via the slide driver of the pickup driver 105.

Then, when the pickup 205 arrives at the target track, the tracking operation is started. As described above, the tracking error signal TE is obtained by taking the difference between the amplitude values of the RF signals reproduced from the two wobble pits in the servo area. The DSP 102 forms a servo loop for tracking control by feeding back tracking control data obtained by digitally filtering this value from the PWM circuit 104 to the pickup driver 105.

The head position of the target sector is detected with tracking applied. As described above, the sector mark STM1 and STM2 are provided in the segment at the beginning of each sector and the segment immediately before that, and each sector mark STM
1, STM2 are the four positions A shown in FIG.
Open a window in B, C, D, and set these four positions A,
When the position of the maximum amplitude in the RF signals sampled in B, C, and D is B, it indicates that it is the head segment of the sector, and when it is C, it is 1 at the head of the sector.
Indicates the previous segment. Basically, the segment at the head of the sector is determined by converting the sector address given by the host computer 300 into a physical sector and calculating which segment of which track the sector is. The probability that different types of sector marks will be defective at the same time is 10 ⁻¹⁰ or less empirically, and the probability of occurrence of defective sectors due to this is extremely small.

Further, the data clock generation (DPLL) circuit 117 generates a data clock DCK which is M / N times the frame-synchronized servo clock SCK obtained by the SPLL circuit 114, and generates this data clock DCK as data. System timing generator (DT
G) Apply to 119 and recording / reproducing circuit 120. The data clock DCK generated by the data clock generation (DPLL) circuit 117 is read clock phase compensation (RCPC) based on the phase in the read clock phase compensation area of the reproduction RF signal of the reference data shown in FIG. The phase is compensated by the circuit 121.

The recording / reproducing circuit 120 is supplied with user data to be recorded from the host computer 300 via the controller 101 in the recording operation mode. The recording / reproducing circuit 120 includes a scramble processing circuit having a configuration as shown in FIG. 13, for example.

The scramble processing circuit shown in FIG. 13 adds 7 stages of flip-flops 131 and outputs of the first stage and the last stage of the flip-flop 131 (EXOR).
And then return to the first stage of the flip-flop 131
Adder 132 and a second adder 133 that adds (EXOR) the output of the first adder 132 and the recording data.
It consists of and. This scramble processing circuit clears the flip-flop 131 at each sector start timing to generate a random number of 127 cycles as shown in the scramble table of FIG. 14, for example, by the first adder 1
32 is generated as an output of 32, and the random number is added (EXOR) to the recording data by the second adder 133 to perform scrambling processing according to Y = X ⁷ + X + 1 in sector units.

In the recording / reproducing circuit 120,
The user data thus scrambled is modulated into NRZI series data synchronized with the data clock DCK. At this time, the initial value is set to “0” for each segment. Then, the modulation signal WDAT is supplied to the magnetic head 211 via the magnetic head driver 210. The magnetic head 211 generates a magnetic field according to the modulation signal WDAT, and the magnetic field is generated by the laser diode 20.
The data area ARd of the magneto-optical disk 201, which has been overheated to the Curie temperature by the laser beam emitted from 7.
The NRZI series data is recorded by applying

During recording, the laser diode 2 is moved at the timing when the pickup 205 moves from the servo area to the prewrite area of the data area.
The laser driver 206 is controlled by the servo system timing generator (STG) 108 so as to switch the reproduction driving power from 07 to the recording driving power.
Then, the recording / reproducing circuit 120 causes the recording / reproducing circuit 120 to record the data of a specific polarity in the pre-write area AR _PR at the timing when the pickup 205 passes through the pre-write area AR _PR. ) 119. The data of the specific polarity means the prewrite area AR _PR.
The data has the same polarity as the bulk erase of. Thus, with respect to the pre-write area AR _PR, by recording the same polarity data and bulk erasing direction, even without data to the pre-write area AR _PR is normally recorded is recorded by residual heat shortage of media Since the data that is present does not change, a stable signal can be reproduced.

In the reproduction operation mode, the reproduction MO signal obtained by the IV conversion & matrix amplifier 209 from the detection output of the photo detector 208 is
After being clamped to an appropriate potential by the selector & clamp 112, it is A / D converted by the A / D converter 113 and supplied to the recording / reproducing circuit 120. And
As shown in FIG. 15, the recording / reproducing circuit 210 includes a threshold detecting circuit 120A and a data detecting circuit 120B, and the partial response (1) is applied to the reproducing MO signal digitized by the A / D converter 113. ，
NRZI series data is decoded by Viterbi decoding after performing a digital filter process according to 1). Then, the NRZI series data is segmented into NR
After being converted into Z-series data, it is descrambled in sector units to be converted into reproduction data, and this reproduction data is transferred to the host computer 300 via the controller 101.

Here, in the threshold value detecting section 120A of the recording / reproducing circuit 120, based on the reproduction signal of the reference pattern recorded in the reference area provided at the beginning of the above-mentioned data sector, the ternary level in data detection is set. The thresholds (high H, medium M, low L) are determined as follows.

That is, as described above, 8T for 4 bytes
As a reproduction signal of a 66-byte reference pattern composed of 4 blocks each including a pattern and a 2T pattern of 12 bytes as one block, and an all 0 pattern of 2 bytes as a margin for setting the detected information. On the other hand, for example, the amplitude values of the 8T pattern sampled in each block are averaged as shown in FIG. 16 as sampling points, and for each block,

[0068]

[Equation 1]

Average values AVla, AVlb on the low level side
AVlc, AVld,

[0070]

[Equation 2]

High level average values AVha, AVhb, AV
Find hc and AVhd.

Next, the average values AVla and AVl on the low level side
Subtraction of all combinations of b, AVlc, and AVld is performed, and the absolute value thereof is taken. Since this is a combination of two selected from four, Slab = ABS (AVla-AVlb) Slac = ABS (AVla-AVlc) Slad = ABS (AVla-AVld) Slbc = ABS (AVlb-AVlc) Slbd = ABS (AVlb -AVld) Six kinds of calculations of Slcd = ABS (AVlc-AVld) are performed. Of these six values, the minimum values Slxy, Slxy = min (Slab, Slac, Slad, Slbc, Slbd,
Slcd) (x = a, b, c, dy = a, b, c, d x! = Y
), The block x with the smallest change
And y, and the two average values AVL = (AVlx + A
Let Vly) / 2 be the amplitude value on the low level side.

By the same calculation, the average value A on the high level side
The amplitude value AVH on the high level side is determined from Vha, AVhb, AVhc, and AVhd.

In the above calculation, in order to simplify the processing, four blocks and four samplings in them are performed and two blocks are averaged. What is the value of these numbers? It may be.

Here, the detection of the edge portion is performed as follows. That is, as shown in FIG. 17, a window is opened at sampling points S0 to S4, an amplitude value is extracted, and a difference between two sampling points apart is calculated. Then, the maximum value of the calculated values Eha0 to Eha2 is searched. Here, as shown in FIG. 17, when the maximum value is Eha1, the following four sampling positions of the saturation level are extracted from the position of the sampling point S4 next to the edge portion, and the above averaging operation is performed. In addition, when the maximum value of the amplitude difference of the edge portion is obtained, the polarity is taken into consideration at the rising edge and the falling edge to reduce the false detection. When the 8T pattern is not continuously recorded in a format, the edge portions that should exist before the low level are separated, but even if they are temporally separated, the falling portion that existed most recently at the low level is used as the edge. Shall be used.

Further, the maximum difference value obtained by these is held as it is, and is used for the defect detection of the saturation level sampled thereafter. For example, as shown in FIG. 18, when the edge amplitude value is EHA, it is checked whether or not the difference between the sampled values next to each other exceeds EHA / 2. It recognizes that there is, and performs a process so that it is not used as a sampling value. In addition, the difference between the neighbors is such as HA0-HA1.

The center level of the signal averages the amplitude information when the phase amount is within a certain set value (Center level reference limit) from the 2T pattern for detecting the phase information as shown in FIG. As a result, CEN = ΣSn can be obtained. The center value CEN of the signal thus obtained can be used for data detection. Further, the reliability of the sampled amplitude information can be improved by using it as a threshold for defect detection.

Further, in the threshold value detecting section 120A of the recording / reproducing circuit 120, the values excluding the maximum value and the minimum value of the averaged value for each block are further averaged to determine the three-valued threshold value. You may That is, with respect to the average values AVla, AVlb, AVlc, and AVld on the low level side, the maximum value AVlmax that is AVlmax = max (AVla, AVlb, AVlc, AVld) and AVlmin = min (AVla, AVlb, AVlc, AVld) are obtained. ) And the minimum value AVlmin, the average value is taken as the amplitude value AVL on the low level side. In this case, the amplitude value AVH on the high level side is similarly obtained.

Further, the threshold detection unit 120A of the recording / reproducing circuit 120 examines the distribution within each block and averages a plurality of values selected from blocks having a small distribution range to determine the above three-value threshold. You can also

That is, the maximum value and the minimum value are obtained from a plurality of values sampled at a predetermined position in each block, and the differences WAl, WBl, WCl, WD between the two values.
Compute l for each block.

BAlmax = max (LA0, LA1, LA2, LA3) BAlmin = min (LA0, LA1, LA2, LA3) WAl = BAlmax-BAlmin WAl, WBl, WCl obtained by the above equation
From WD1, select two blocks with smaller values.
In each block, as described above, the average value AV within the block
la to AVld are obtained, and the amplitude value AVL is determined using the average value of the two selected blocks.

The small distribution of each block is WX1, W
If Y1 is set, the amplitude value on the low level side to be obtained is AVL = (AVlx + AVly) / 2. The amplitude value AVH on the high level side is similarly obtained.

Amplitude value AV calculated as described above
Using L, AVH, the threshold values TH, TL, CEN required for decoding by PR (1, 1), that is, partial response class 1, are obtained as follows.

Center value CEN = (AVH + AVL) / 2 Upper threshold value TH = CEN + (AVH−AVL) / 4 Lower threshold value TL = CEN− (AVH−AVL) / 4 Further, amplitude values CENTER, S used for Viterbi decoding.
H and SL can be obtained as follows.

CENTER = (AVH + AVL) / 2 SH = (AVH-AVL) / 2 SL = (AVL-AVH) / 2 Based on the value thus obtained, for example, Japanese Patent Laid-Open No.
The recording is reproduced according to the procedure disclosed in Japanese Patent Publication No. 225638.

[0086]

As described above, in the magneto-optical disk recording method according to the present invention, the concentric or spirally formed tracks are divided into a plurality of regions each consisting of a servo area and a data area. For the disc,
A reference pattern in which a pattern whose N-value threshold can be detected is divided into several blocks and which is periodically arranged with N units as one unit is recorded together with data in each sector in a data area. It becomes possible to reliably reproduce the data by determining the threshold value of the N value.

In the reproducing method and reproducing apparatus for a magneto-optical disk according to the present invention, a magneto-optical disk in which concentric or spiral tracks are divided into a plurality of areas each consisting of a servo area and a data area , A pattern in which the threshold value of the N value can be detected is divided into several blocks, and a reference pattern which is periodically arranged with N units as one unit is reproduced from the data area in which each sector is recorded together with data. By determining the threshold value of the N value based on the signal, it is possible to reliably reproduce the data.

Further, in the reproducing method and reproducing apparatus for the magneto-optical disk according to the present invention, the value of each block is averaged to determine the threshold value of the above N value, so that the defect of the magneto-optical disk or the adhesion of dust etc. Even if a relatively long amplitude fluctuation or a sudden amplitude fluctuation occurs due to the influence, it is possible to reliably determine the threshold value of the N value and reproduce the data.

In the reproducing method and reproducing apparatus for a magneto-optical disk according to the present invention, the averaged value A for each block is
By further averaging a plurality of combinations of average values selected from the ones having a small difference in all combinations of _m C _{2 of} V _m to determine the threshold value of N value, the threshold value of N value is surely determined. Data can be reproduced.

Further, in the reproducing method and reproducing apparatus for the magneto-optical disk according to the present invention, the average value excluding the maximum value and the minimum value of each block is further averaged to obtain the above N.
By determining the value threshold, it is possible to reliably determine the N value threshold and reproduce the data.

Further, in the magneto-optical disk reproducing method and reproducing apparatus according to the present invention, the above-mentioned N is obtained by using the value at the position distant by the predetermined number of samples from the maximum position of the edge existing in the window for the reproduced signal of the reference pattern. By determining the value threshold, it is possible to reliably determine the N value threshold and reproduce the data.

In the reproducing method and reproducing apparatus for a magneto-optical disk according to the present invention, the distribution in each block is examined, and a plurality of values selected from blocks having a small distribution range are averaged to set the threshold value of the N value. decide.

In the reproducing method and reproducing apparatus for the magneto-optical disk according to the present invention, when the sampled value of the saturated portion exceeds a certain ratio with respect to the amplitude difference of the edge portion of the reproduced signal of the reference pattern, By determining the N value threshold value as a defect, the N value threshold value can be reliably determined and the data can be reproduced.

Further, in the reproducing method and reproducing apparatus for a magneto-optical disk according to the present invention, a defect is detected by using the amplitude information sampled when the clock phase is near 0 in the reference pattern phase detection pattern as a threshold, By determining the threshold value of the N value, N
It is possible to reliably determine the threshold value and reproduce the data.

[Brief description of drawings]

FIG. 1 is a diagram showing a segment structure of a magneto-optical disk used in an embodiment of a recording method, a reproducing method and a reproducing apparatus for a magneto-optical disk according to the present invention.

FIG. 2 is a diagram showing a format of a servo area in the magneto-optical disc.

FIG. 3 is a diagram showing a method of detecting a first pit in a servo area of the magneto-optical disk.

FIG. 4 is a diagram showing a format of an access code recorded in an address segment in the magneto-optical disc.

5 is a diagram showing a part of an access code recorded in the address segment shown in FIG.

FIG. 6 is a diagram showing a format of a data segment in the magneto-optical disc.

FIG. 7 is one frame and one in the magneto-optical disk.
It is a figure which shows the structure of a data sector.

FIG. 8 is a diagram showing a data format of a data sector in the magneto-optical disk.

FIG. 9 is a diagram showing a reference pattern recorded in a data sector of the magneto-optical disc.

FIG. 10 is a diagram showing a format of a data sector in the magneto-optical disk.

FIG. 11 is a block diagram showing a configuration of a recording / reproducing apparatus according to the present invention in which the magneto-optical disk is used as a recording medium.

FIG. 12 is a timing chart showing sampling timing for extracting clock information from a reproduction RF signal waveform of wobble pits in the recording / reproducing apparatus.

FIG. 13 is a block diagram showing a configuration of a scramble processing circuit provided in a recording / reproducing circuit in the recording / reproducing apparatus.

FIG. 14 is a diagram showing a scramble table of the scramble processing circuit.

FIG. 15 is a block diagram showing a main configuration of a recording / reproducing circuit in the recording / reproducing apparatus.

FIG. 16 is a diagram showing sampling points of a reproduction signal of a reference pattern in the recording / reproducing apparatus.

FIG. 17 is a diagram for explaining an edge detection method of a reproduction signal of a reference pattern in the recording / reproducing apparatus.

FIG. 18 is a diagram for explaining a defect detection system of a reproduction signal of a reference pattern in the recording / reproducing device.

FIG. 19 is a diagram for explaining a method of detecting a center level of a reproduced signal in the recording / reproducing apparatus.

[Explanation of symbols]

 100 Control Circuit Block 120 Recording / Reproducing Circuit 120A Threshold Detection Unit 120B Data Detection Unit 200 Disk Drive 201 Magneto-Optical Disk

Claims (17)

[Claims] 1. A recording method for a magneto-optical disk in which a concentric or spiral track is divided into a plurality of areas each consisting of a servo area and a data area, and a pattern capable of detecting a threshold value of N value. Is divided into several blocks, and a reference pattern in which N pieces are arranged periodically as one unit is recorded in a data area together with data for each sector, and a recording method for a magneto-optical disk. 2. A reproducing method for a magneto-optical disk in which concentric or spiral tracks are divided into a plurality of areas each consisting of a servo area and a data area, and a pattern capable of detecting a threshold value of N value. Is divided into several blocks, and a reference pattern in which N pieces are arranged periodically as one unit is recorded together with data in each sector, and a threshold value of N value is determined based on a reproduction signal of the reference pattern. Then, a method for reproducing a magneto-optical disk is characterized by reproducing data. 3. The method of reproducing a magneto-optical disk according to claim 2, wherein the value of each block is averaged to determine the threshold value of the N value. 4. The _m C of the averaged value AV _m for each block
4. The method of reproducing a magneto-optical disk according to claim 3, wherein a combination of a plurality of average values selected from one having a smaller difference between all _two combinations is further averaged to determine the threshold value of the N value. 5. The magneto-optical disk according to claim 3, wherein the threshold value of the N value is determined by further averaging the averaged values of the blocks except the maximum value and the minimum value. How to play. 6. The threshold value of the N value is determined by using a value at a position distant by a predetermined number of samples from the maximum position of the edge existing in the window for the reproduction signal of the reference pattern. Reproducing method of magneto-optical disk. 7. The magneto-optical disk according to claim 2, wherein the distribution in each block is examined, and a plurality of values selected from blocks having a small distribution range are averaged to determine the threshold value of the N value. How to play. 8. The threshold value of the N value is determined as a defect when the sampled value of the saturated portion exceeds a certain ratio with respect to the amplitude difference of the edge portion of the reproduction signal of the reference pattern. The method of reproducing a magneto-optical disk according to claim 2. 9. The threshold value of the N value is determined by detecting a defect using the amplitude information sampled when the clock phase is near 0 in the phase detection pattern of the reference pattern as a threshold value. 2. The method for reproducing the magneto-optical disk according to 2. 10. A track formed concentrically or spirally is divided into a plurality of areas each consisting of a servo area and a data area, and a pattern capable of detecting a threshold value of N value is divided into several blocks and N pieces are divided. A reproducing apparatus for a magneto-optical disk in which a reference pattern periodically arranged as one unit is recorded together with data in the data area for each sector, and a track provided in the magneto-optical disk is optically scanned. Data for detecting data from the signal obtained by the optical head by using the threshold value detecting means for detecting the threshold value of N value from the signal obtained by the optical head and the threshold value of N value decided by the threshold detecting means. A threshold value of the N value is determined based on the reproduction signal of the reference pattern by the threshold value detection means, A reproducing device for a magneto-optical disk characterized by reproducing data. 11. The reproducing apparatus for a magneto-optical disk according to claim 10, wherein the threshold value detecting means has an averaging processing means for averaging the values of the respective blocks to determine the threshold value of the N value. . 12. The averaging means further averages a combination of a plurality of average values selected from the ones having a smaller difference among all _m C ₂ combinations of the averaged values AV _m of each block. 12. The magneto-optical disk reproducing apparatus according to claim 11, wherein the threshold value of the N value is determined. 13. The averaging means determines the threshold value of the N value by further averaging the averaged values excluding the maximum value and the minimum value of each block. 11. A reproducing device for a magneto-optical disk according to item 11. 14. The threshold value detecting means determines the threshold value of the N value by using a value at a position distant by a predetermined number of samples from a maximum position of an edge existing in a window for a reproduction signal of the reference pattern. The magneto-optical disk reproducing apparatus according to claim 10. 15. The threshold value detecting means examines a distribution in each block, and averages a plurality of values selected from blocks having a small distribution range to determine the threshold value of the N value. 10. A reproducing device for a magneto-optical disc according to 10. 16. The threshold value detecting means detects the threshold value of the N value as a defect when the sampled value of the saturated portion exceeds a certain ratio with respect to the amplitude difference of the edge portion of the reproduction signal of the reference pattern. 11. The reproducing apparatus for a magneto-optical disk according to claim 10, which is determined. 17. The threshold value detecting means detects a defect by using amplitude information sampled when a clock phase is near 0 in the phase detection pattern of the reference pattern as a threshold value, and determines the N value threshold value. The reproducing apparatus for a magneto-optical disk according to claim 10, wherein.