JPH10308071A - Recording medium, signal reproducing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a device to detect early the position of the circumference direction and a servo frame number without reducing the recording region of a recording medium by providing position information of the circumference direction in a gray code region in which the gray code corresponding to track position information in a servo region for each servo frames obtained by dividing a recording track is recorded. SOLUTION: Position information of the circumference direction SCI and track position information TR1 are recorded in a gray code region GE of plural servo frames SF1, SF2,... constituted by each track of a disk. The position information of the circumference direction SCI is information relating to a block position and information indicating a block number or the like in which the position information of the circumference direction is recorded. A disk reproducing device can recognize a block number positioned at present by detection of the position information of the circumference direction and further can shorten an access time to the objective servo frames SF1, SF2,....

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording medium having a data recording area divided for each servo frame, and a signal reproducing apparatus and method for reproducing a recording medium having a data recording area divided for each servo frame. About.

[0002]

2. Description of the Related Art Data recorded on a disk of a recording medium such as a magnetic disk or an optical disk is accessed with reference to an address written for each data, for example, a track number and a sector number. For example, a disc reproducing apparatus for reproducing the above-mentioned optical disc makes an on-track on a target track of a rotating disc and accesses a sector in which desired data is written while checking a sector number.

[0003] As shown in FIG. 8, the optical disk has a sector composed of a data portion DP and a header portion HP, and information such as a sector number is recorded in the header portion HP. The track number is written as a gray code in a servo area in a servo frame which is a unit of servo processing.

As shown in FIG. 9, in a servo area SE in which a gray code is recorded, burst patterns BP _A , BP _B , and so on adopting a so-called embedded servo system.
BP _C and BP _D are recorded.

[0005] The above-described gray code usually records track position information which is a track number as described above. The gray code can be read even when the servo is unstable or not applied, so that the disc reproducing apparatus can quickly access the target track and always set the track position. You can figure out.

The above burst patterns BP _A , BP _B , BP
_C and BP _D are signals for tracking error detection, and the tracking servo uses the burst pattern BP
_A, BP _B, BP _C, while detecting the BP _D performed. Burst signal _{BP A, BP B, BP C} , BP D are recorded from a single frequency, for example, the signal read head so that the signal amplitude reproduced from the BP _A and BP _B are the same has traveled Sometimes it's just on track.

The servo area SE is recorded on each track, and a track number is detected and tracking servo is performed with reference to a gray code and a burst pattern recorded in the servo area, and the on-track is recorded. After that, the target sector is detected.

[0008] The detection of the target sector is performed by referring to the header information of the data. That is, the sector number recorded in the header information is read, and the target sector is determined and detected.

As described above, data in a desired sector is accessed by detecting the track number and the sector number.

In recent years, in order to increase the recording density on a disk, a so-called data format without header information, in which header information for recording a sector number has been removed, has been adopted. In the data format without header information, since there is no header information, it is not possible to recognize the servo frame position where the sector exists and the sector position in the servo frame. That is, it is impossible to determine whether the servo frame and the sector in which the data is recorded are the target servo frame and the sector only by reading the data.

For example, in the case of an optical disk employing the above-mentioned data format without header information, as means for accessing a target sector position, means for detecting a servo area and means for detecting a servo area, There is a means for detecting and performing the frame number recorded in the.

In the means for detecting a servo area and accessing a target sector position, for example, as shown in FIGS. 10A and 10B, each time a servo area SE of each servo frame SF appears, A counter to be counted up is prepared, the arrival of the target servo frame position is detected based on the value of the counter, and then the sector number is compared with the sector number information obtained in advance to access the target sector. I do.

As shown in FIG. 11, the counter 200 counts servo area pulses detected for each servo area and outputs information on the servo frame position obtained by counting.

In order to detect a target servo frame by counting with the counter 200,
It is necessary to determine a reference servo frame, that is, clear the counter 200 in the reference frame.

As a method for initializing the counter 200, there is a means for utilizing an index pulse generated in synchronization with the rotation of the disk as shown in FIGS. 12 (a) and 12 (b). Here, the index pulse is a pulse signal recorded in a servo area of a servo frame used as a reference on the disk.

As shown in FIG. 13, the counter 200
The absolute position of the servo frame SF can be known by clearing the head position of the servo frame using the index pulse and counting the number of servo frames based on this position.

The servo area S of the servo frame SF
There is also a means for detecting the servo frame position information recorded in E and accessing the target sector position.
The target servo frame SF is accessed by detecting the servo frame number recorded in E, and then the target sector is accessed by comparing it with sector number information obtained in advance. In this means, the servo frame position information is read at the same time as the track on which the target sector is recorded is on-track.

[0018]

In the means for detecting the servo area SE and accessing a target sector position, the counter 2 is required to wait for generation of an index pulse which appears once in one rotation while rotating the optical disk.
00 cannot be cleared. In other words, even if the target track is on-track, there is an average waiting time of 1/2 turn. This degrades the access time.

In the means for detecting the servo frame position information recorded in the servo area SE of the servo frame SF and accessing the target sector position, the servo frame position information is newly recorded in the servo area. The longer the servo information area, the smaller the area of the recording surface that can be used to record data,
The recording capacity of the optical disk is reduced. The servo area SE exists around 100 in one round, and its ratio to the total area of the optical disk is close to 10%, which is not negligible.

Therefore, the present invention has been made in view of the above circumstances, and it is an object of the present invention to detect a circumferential position and a servo frame number at an early stage without reducing a data recording area of a recording medium. It is an object of the present invention to provide a recording medium and a signal reproducing apparatus and method which enable the recording medium.

[0021]

In order to solve the above-mentioned problems, a recording medium according to the present invention has a servo area in which a servo pattern signal is recorded for each servo frame obtained by dividing a recording track. The circumferential position information is provided in a gray code area where a gray code corresponding to the track position information in the servo area is recorded.

In order to solve the above-mentioned problems, a signal reproducing apparatus according to the present invention includes a tracking error detecting means for performing a tracking error signal, and an on-track based on a tracking error signal detected by the tracking error detecting means. After that, a circumferential direction information discriminating means for discriminating circumferential position information recorded in the gray code area is provided. With this configuration, the signal reproducing device determines whether information recorded in the gray code area is circumferential position information after on-track.

In order to solve the above-mentioned problems, the signal reproducing method according to the present invention includes a tracking error detecting step for detecting a tracking error signal by a tracking error detecting means, and a tracking error detected in the tracking error detecting step. A circumferential position information determining step of determining circumferential position information recorded in the gray code area after performing on-track based on the signal.

[0024]

Embodiments of the present invention will be described below.

As an embodiment of the recording medium according to the present invention, a disk which is a disc-shaped recording medium is assumed. This disk has a substrate diameter of 3.5 inches, and records information signals by magnetizing a signal recording surface formed on the substrate. This disc is configured to be removable from the playback device.

In this disc, in order to detect a block having a plurality of servo frames, information on the above-described block position is added to the gray code which is usually track position information recorded in the gray code area in the servo area. Circumferential position information is recorded.

In the disk, as shown in FIG. 1, each track is composed of a plurality of servo frames SF ₁ , SF ₂ ,. In this disk, tracking servo is performed for each servo frame, and data such as servo frame position information recorded in the servo frame is reproduced.

As shown in FIG. 2, the disk has a plurality of tracks TR ₁ , TR ₂ ,.
_m-1 and TR _m are formed, and servo frames SF ₁ , SF ₂ ,..., SF ₈ ,.
.., SF _n are formed. For example, disk 1 has 9
6 servo frames. In the disk 1, one block is formed in a radial direction from a plurality of servo frames.

For example, the disk 1 forms one block BL with 12 servo frames. Therefore, in this case, the disk 1 is composed of eight blocks BL each having 12 servo frames as blocks. The disk 1 records circumferential position information, which is information on block positions, in a gray code area GE.

As shown in FIG. 1, the servo frame SF ₁ includes a data area DE in which normal data is recorded,
Servo area SE in which various data for servo is recorded
It is composed of The servo frame SF ₂ that next to each other in the servo frame SF ₁ is recorded, records the data by the same data format as the servo frames SF _1.

An automatic gain control signal (AGC) and a servo timing mark (STM) are recorded in the servo area SE. In the servo area SE, a burst pattern B for tracking servo is used.
_{P A, BP B, BP C} , are provided a tracking servo information area TE that records BP _D.

The above-mentioned auto gain control signal, servo timing mark, gray code area GE and tracking servo information area TE are provided on a recording track in the servo area SE in a time-division manner. The auto gain control signal is a signal for synchronizing bits, and is used for an AG of a disc reproducing apparatus for reproducing the data.
This is a signal for clamping the C amplifier. The servo timing mark is a bit synchronization signal for detecting various data recorded in the gray code area GE and the tracking error information area TE after the time axis.

In the gray code area, GE records circumferential position information SCI and track position information TRI.

As described above, the circumferential position information SCI is information on a block position, and is information indicating a block number or the like in which the circumferential position information SCI is recorded. The track position information is information indicating a track number or the like in which the track position information TRI is recorded.

For example, the gray code area GE in which the circumferential position information SCI and the track position information are recorded is a coded data area composed of binary 16 bits as shown in FIG. The gray code area GE is an area in which only the gray code that is the track position information TRI is normally recorded.

The disk 1 according to the embodiment has track position information TR normally recorded in the gray code area GE.
Along with I, circumferential position information SCI is recorded. For example, the circumferential position information SCI is encoded with 3 bits,
The track position information TRI is encoded with 12 bits.

The track position information TRI indicates an absolute track number in which one bit differs between adjacent tracks. Even if the reproducing head for reproducing the data recorded on the disk 1 crosses the track position information TRI for two tracks, the value reproduced from the reproducing head is the track number of one of these two tracks. Is shown. Further, for example, even when the head crosses the track position information TRI for three tracks in the high-speed seek mode, the value reproduced from the reproducing head is a track number at most two tracks away from the center track. Is shown.

As described above, the circumferential position information SCI indicates a block number in which the circumferential position information SCI is recorded. The disc reproducing apparatus that reproduces the disc 1 can know the block number of the current position by detecting the circumferential position information SCI.
The access time to the target servo frame can be reduced.

For example, in consideration of the fact that the disc 1 is composed of 8 blocks and that the same block position information is used within the same block, the 3-bit encoded circumferential position information SCI is ( (000) b to (111) b. That is, the block numbers to all of the servo frame of the first block BL ₁ assigns a (000) b, a block number to every servo frame in the second block BL ₂ (00
1) Allocate b, and assign (111) b as the block number to the servo frame in the eighth block.

It should be noted that, in the gray code area GE, an area for recording the circumferential position information SCI is secured, for example, in the above-described case, the three bits are used for the track position information TRI in the gray code area GE which has been conventionally performed. That is, it may be performed to such an extent that the area of the gray code can be secured.
In other words, in other words, provided that the track position information is recorded in the gray code area GE, the circumferential position information SCI is stored in the other unused gray code areas GE.
Is recorded, and the circumferential position information SCI is recorded for all the servo frames SF in the reserved area. If this condition is satisfied, the circumferential position information SCI and the track position information TRI can be read from all the servo frames SF.

As described above, the circumferential position information SCI including the block number coded in each block,
The disc player can know the block number of the current position.

The circumferential position information SCI may be simply recorded in the gray code area GE of at least one servo frame in the same block. For example, only the earliest servo frame in the block records the circumferential position information SCI in the gray code area GE. As described above, when the circumferential position information SCI is recorded in the gray code area GE of at least one servo frame in the same block, for example, in order to identify the circumferential position information SCI, One bit is set to the identification flag FL. For example, as shown in FIGS. 3A and 3B, the most significant bit of the gray code area GE is used for the identification flag FL. Then, the identification flag FL
Represents the circumferential position information SC in the gray code area GE.
When I is recorded, the identification flag FL is set to, for example, 1. When the circumferential position information SCI is not recorded in the gray code area GE and the track position information TRI is recorded, the identification flag FL is set to 0. To

By recording the identification flag FL in the gray code area GE in this way, the disc reproducing apparatus can check whether the circumferential position information SCI is recorded in the gray code area GE only by checking the identification flag FL. Can be identified.

As described above, when the circumferential position information SCI is recorded in the gray code area GE only in the earliest servo frame in the block, the identification in the earliest servo frame in the block is performed. Since only the flag FL becomes 1, the disc reproducing apparatus can know the boundary between blocks and the position of the earliest servo frame in the block. Even when the circumferential position information SCI is recorded in all the servo frames of the disk 1, the disk reproducing apparatus changes the lower bits of the circumferential position information SCI from 0 to 1 and from 1 to 0. By detecting the fact, it is also possible to know the boundary of the block and the position of the earliest servo frame in the block. Thus, in the block, the first servo frame SF
Is used for identifying the block in the same way as when the circumferential position information SCI is recorded in all the gray code areas GE in the block BL described above.

[0045] The servo area SE of the gray code area GE are provided, as shown in FIGS. 1 and 3, tracking servo information burst patterns _{BP A, BP B, BP C} , the BP _D are recorded An area TE is provided.
The tracking servo information area TE is a data area provided for detecting a tracking error signal, and includes burst patterns BP _A , B P recorded in this area.
Tracking servo is performed based on a tracking error signal obtained by reproduction of P _B , _B P _C , and _B P _D.

The above burst patterns BP _A , BP _B , BP
_C, BP _D is a pattern signal, each of which is a single frequency recording. Burst patterns BP _A , BP _B , BP _C , BP _D
Have different widths T each along the track center axis.
_P: is formed by (T _P track pitch), C layer burst pattern BP _C, the track central axis (odd track center axis of the track), D layer burst pattern BP _D are track center axis (track of the even track Center axis), A-layer burst pattern BP _A and B-layer burst pattern BP
_B is formed by being displaced a C layer burst pattern BP _C and D layer burst pattern BP _D in the radial direction by T _P / 2. That is, each burst pattern BP _A , BP _B , BP
_C, BP _D are the various radially to form the desired solid printing with a width T _P to 1 track pitch T _P intervals.

The burst patterns BP _A , BP _B , BP
For _C, BP _D is formed at 2T _P position in the radial direction,
If the 2T _P and 360 °, burst patterns BP _A,
BP _B, BP _C, BP _D phase a variety 0 °, 180 °,
90 ° and -90 °.

For example, the burst patterns BP _A , B
P _B, BP _C, by BP _D, the servo signals U _A, U _B,
U _C, when obtaining the U _D, the equation (1) and (2) to obtain the track position signal U _X and U _Y.

[0049] _{U X = k (U A -U} B) / (U A + U B) ··· (1) U Y = k (U C -U D) / (U C + U D) ··· (2 ) here, the value K is the ratio of the width T _W and the track pitch T _P of the reproducing head (T _W / T _P).

The track position signals U _X and U _Y change periodically with a period of 2T _P (= 360 °) in a state where they differ from each other by 90 ° as a position function in the radial direction R of the disk 1.
The position in the radial direction is defined as an area RA ₂ where U _Y > 0 near the center axis of the track of the even address, an area RA ₄ where U _Y <0 near the center axis of the track of the odd address, and the center axis of the track. dividing the region RA ₃ of 0 <U _X in the region between the central axis of the region RA ₁ and track 0> U _X between.

Here, in the areas RA ₁ and RA ₃ , the position signal U _Y is linear, and in the areas RA ₂ and RA ₃ , the position signal is linear. When the reproduction head is roughly positioned within the range of one track, the final positioning can be performed in the entire area in the radial direction R by using the narrow range track position signal.

By providing the tracking servo information area TE in which the information for detecting the tracking error signal is recorded, the disk reproducing apparatus can control the tracking servo based on the burst pattern recorded in the tracking servo information area TE. After performing on-track on the target track, the circumferential position information SCI in the gray code area GE can be detected.

As described above, the disc 1 records the circumferential position information SCI in the gray code area GE,
This enables early detection of a block number and detection of a servo frame position by a disk reproducing device.

That is, when the disk reproducing apparatus reproduces the disk formed as in the present embodiment, a maximum of 45
During the rotation, it is possible to know the positional relationship between the servo frame that is currently located and the servo frame having the sector where the desired data is recorded.

The disk 1 has a gray code area G
By providing an identification flag in E, the gray code area GE
Can be identified.

Since the disc 1 records the circumferential position information SCI in the gray code area GE,
The servo area SE is not lengthened. Therefore, the recording capacity of the disk 1 does not decrease by recording the circumferential position information SCI.

As shown in FIG. 4, the data area DE of the disk 1 includes a voltage control signal (VCO), a sector mark (SM), data, and an error correction code (EC).
C) is time-divisionally recorded to form a sector. This sector has a so-called data format without header information. In FIG. 4, ISG indicates a gap between each sector.

The above-mentioned data is main data, for example, compression-coded image data. The error correction code is a code for correcting an error in a bit by the disc reproducing apparatus when the error occurs in the bit. The voltage control signal is a bit synchronization signal for reading data by the disk reproducing device.

The sector mark is recorded in each sector, and the disk reproducing apparatus reads a pulse signal by reproducing the sector mark. Then, the disc reproducing apparatus can determine whether the sector currently located is the target sector by counting the pulse signals.

Therefore, the disc reproducing apparatus positions the reproducing head at the target servo frame based on the circumferential position information SCI recorded in the gray code area GE of the servo area SE, By counting the sector marks recorded in one sector, the sector can be located at a desired sector.

The data area of the disk 1 is not limited to the data format without header information, but may be configured to have header information.

Further, servo frame position information SFI can be recorded in place of the track position information TRI.
In this case, as shown in FIG.
Is used to determine whether the information recorded in the gray code area GE is the track position information TRI or the servo frame position information SFI. For example, when the track position information TRI is recorded in the gray code area GE, the identification flag FL is set to 1, for example, and when the servo frame position information SFI is recorded instead of the track position information RTRI, The identification flag FL is set to 0.

As described above, instead of the track position information TRI, the servo frame position information S is stored in the gray code area GE.
By recording the FI, the disc 1 enables the disc reproducing apparatus to detect the servo frame number early.

The recording medium according to the present invention is not limited to the disk assumed in the above-described embodiment, but can be applied to a hard disk provided in a reproducing apparatus.

Next, embodiments of the signal reproducing apparatus and method according to the present invention will be described. In the present embodiment, a signal reproducing apparatus and method according to the present invention are described as follows. A gray code area in which a recording track is divided for each servo frame and a gray code corresponding to track position information is recorded in a servo area in the servo frame. This is a disc reproducing apparatus configured to reproduce a disc which is a disc-shaped recording medium having the following.

As shown in FIG. 6, the disc reproducing apparatus includes a tracking error detecting circuit 66, a DSP circuit 63, and a tracking error detecting circuit for detecting circumferential position information, which is a block number recorded on the disc. Is configured. Then, the disc reproducing apparatus 1 is configured to convert the block number obtained by detecting the circumferential position information into a servo frame number. In addition, disk 1
00 is, for example, a disk assumed in the above embodiment.

The above-mentioned disc reproducing apparatus 50
A floating reproducing head 51 for irradiating light on the signal recording surface of No. 00 and reading an information signal based on the reflected light; a signal amplifying circuit 52 for amplifying and outputting a reproduced signal output from the reproducing head 51; A digital signal processing circuit 53 for digitizing and outputting the reproduced signal amplified by the signal amplifying circuit 52, and a PLL circuit 54 for synchronizing the digital signal output from the digital signal processing circuit 53 with a clock and outputting the digital signal to a subsequent circuit. , An encoder / decoder 55 synchronized with a PLL circuit 54 for decoding digital signals, etc., and an ECC circuit 56 for error-correcting digital signals decoded and output from the encoder / decoder 55.
And a RAM 57 for temporarily storing the digital signal output from the ECC circuit 56, and a host computer 65 for controlling the output of the digital signal recorded in the RAM 57 and the like.
And

The disc reproducing apparatus 50 includes a rectifying circuit 59 for rectifying and outputting the reproduced signal output from the signal amplifying circuit 52, and a PLL circuit for outputting the reproduced signal output from the rectifying circuit 59 in synchronization with a clock. 60, a servo timing mark (STM) detection circuit 61 for detecting a servo timing mark included in the signal output from the PLL circuit 60 and outputting a synchronization signal, and a synchronization signal output from the servo timing mark detection circuit 61. A gray code area detection circuit 62 for reading information in the gray code area of the disk in synchronization with the gray code area detection circuit 6
A digital operation processing (DSP) circuit 63 for performing processing such as discrimination processing on information in the gray code area detected by step 2;
A frame number counter 64 for calculating a servo frame number based on the servo frame position information output from the digital arithmetic processing circuit 63;
Flash memory 6 for recording the processing results by 3
5, a tracking error detection circuit 66 for detecting a tracking error signal based on the signal output from the rectification circuit 59, and a signal output from the digital operation processing circuit 63, for example, a track seek signal and the like. A mixing circuit 67 for sending the output tracking error signal to the reproducing head 51 and a spindle motor 68 for rotating the disk 100 are provided.

Hereinafter, a circuit for detecting the position information in the circumferential direction in the disk reproducing apparatus 50 and converting the information to the servo frame number will be described in more detail.

The servo timing mark detection circuit 61
A bit synchronization signal is generated from the input signal based on a servo timing mark signal recorded in a servo area of the disk 100.

The gray code detection circuit 62 detects a gray code area in the servo frame based on the bit synchronization signal from the servo timing mark detection circuit 61.
The gray code area detection circuit 62 notifies the digital arithmetic processing circuit 63 that a gray code area has been detected.

The digital operation processing circuit 63 performs a discrimination process on the information recorded in the gray code area in response to the detection by the gray code area detection circuit 62. The procedure of the determination process is performed according to a flowchart as shown in FIG.

First, as shown in step S1, the digital arithmetic processing circuit 63 reads track position information of the gray code area. Subsequently, as shown in step S2, the digital arithmetic processing circuit 63 determines whether the track is the target track based on the track position information read from the gray code area.

If it is determined in step S2 that the track is the target track based on the track position information, the digital arithmetic processing circuit 63 determines in step S3 that the gray code area GE in which the track position information has been recorded.
It is determined whether or not the identification flag in is “1”.

The identification flag is provided in the gray code area for identifying the circumferential position information as described in the above embodiment, and when the value is 1, the gray code area is set. Is a flag for identification indicating that the circumferential position information is recorded in the.

If it is determined in step S3 that the identification flag is 1, that is, the circumferential position information is recorded as described above, the digital arithmetic processing circuit 63
Proceed to step S4.

If it is determined in step S2 that the track is not a target track, or if it is determined in step S3 that the identification flag is not 1, the digital arithmetic processing circuit 63 returns to the next input of the gray code area information. Is read, and the processing of steps S1 and S3 is performed.

In step S4, the digital arithmetic processing circuit 63 decodes the circumferential position information recorded in the gray code area where the identification flag is 1, and obtains a block number. After obtaining the block number, the digital operation processing circuit 62 performs conversion to the servo frame number based on the obtained block number.

For example, the conversion into the servo frame number based on the block number is performed based on the relationship between the block number indicating the absolute address on the disk 100 and the servo frame on which the block number is recorded.

After converting the block number into the servo frame number in step S5, the digital arithmetic processing circuit 63 loads the servo frame number counter 64 with the servo frame number as shown in step S6.

The digital operation processing circuit 63 obtains the servo frame number by converting the block number and the block number according to the procedure described above.

Based on the servo frame number thus obtained, the digital arithmetic processing circuit 63 detects the servo frame number at which the reproducing head 51 is currently located by the servo frame number counter 64.

That is, the servo frame number counter 6
4 counts servo frames based on the servo frame number sent from the digital arithmetic processing circuit 63. For example, when the servo frame has only the track position information recorded in the gray code area, the servo frame number counter 64 increments the already obtained servo frame number by +1 and the reproducing head 51 is currently positioned. The servo frame number in which the track position information is recorded is detected. Then, the servo frame number detected by the servo frame number counter 64 is sent to the digital arithmetic processing circuit 63.

The disc reproducing apparatus 50 can know the servo frame number of the current position by the digital processing circuit 50. Disc playback device 50
Can know the relationship between the current position and the position of the servo frame in which the target data is recorded by knowing the servo frame number where the current position is. For example,
The position of the servo frame where the target data is recorded can be obtained from the address information.

Therefore, for example, when the recording track is divided into eight blocks, the disc reproducing device 50
Can know the block number and the servo frame number that are currently located while rotating the disk 100 by a maximum of 45 °, and can know the relative position with the servo frame in which the target data is recorded. Then, after accessing the servo frame in which the target data is recorded, the disk reproducing device 50 counts the sector mark recorded in the data area, so that the sector in which the target data is recorded is recorded. Can be accessed.

In the disk reproducing apparatus 50, the tracking error detection circuit 66 detects a burst pattern recorded in the servo area of the disk 50 to detect a tracking error signal, and based on the detected tracking error signal. The reproducing head 51 is operated to perform tracking servo. Then, the disk reproducing device 50
After performing tracking servo and performing on-track, the above-described circumferential position information is detected.

[0087]

The recording medium according to the present invention has a servo area in which a servo pattern signal for each servo frame obtained by dividing a recording track is recorded, and a gray level corresponding to track position information in this servo area. By having the circumferential position information in the gray code area where the code is recorded, early detection of the circumferential position is possible without reducing the data recording area.

The recording medium converts the position information in the circumferential direction into a servo frame number, thereby enabling early detection of the servo frame number. In addition, the access time to the sector can be reduced.

Further, the signal reproducing apparatus according to the present invention comprises: a tracking error detecting means for detecting a tracking error signal; and an on-track based on the tracking error signal detected by the tracking error detecting means.
By including circumferential position information determining means for determining circumferential position information recorded in the gray code area,
After the on-track, the information in the gray code area can be determined to obtain the circumferential position information.

Therefore, the signal reproducing apparatus can detect the circumferential position information recorded in the gray code area, and thus determines the servo frame number based on the detected circumferential position information. In addition, the access time to the servo frame and the sector in which the target data is recorded can be reduced.

In the signal reproducing method according to the present invention, a tracking error detecting step of detecting a tracking error signal by the tracking error detecting means, and a grayscale after the on-track based on the tracking error signal detected in the tracking error detecting step. Having a circumferential position information discriminating step of discriminating circumferential position information recorded in the code area, after on-tracking, discriminating information in the gray code area, and determining the circumferential position information. Obtainable.

Therefore, in the signal reproducing method, since the circumferential position information recorded in the gray code area can be detected, the servo frame number is obtained based on the detected circumferential position information. In addition, the access time to the servo frame and the sector in which the target data is recorded can be reduced.

[Brief description of the drawings]

FIG. 1 is a data configuration diagram showing details of a block of a disc which is an embodiment of a recording medium according to the present invention.

FIG. 2 is a configuration diagram of a data recording area of the disk, which includes a plurality of block servos.

FIG. 3 shows a servo area in the servo frame.
FIG. 5 is a configuration diagram of a gray code area in which an identification flag, circumferential position information, and track position information are recorded.

FIG. 4 is a diagram showing a data structure of a sector constituting a data area of the disk, wherein the sector has a header-less data format.

FIG. 5 shows a servo area in the servo frame,
FIG. 4 is a configuration diagram of a gray code area in which servo frame position information is recorded instead of track position information.

FIG. 6 is a circuit configuration diagram showing a disk reproducing apparatus which is an embodiment of the signal reproducing apparatus and method according to the present invention.

FIG. 7 is a flowchart showing a discrimination procedure when a digital arithmetic processing circuit included in the disc reproducing apparatus discriminates servo frame position information.

FIG. 8 is a data configuration diagram in which sectors forming a data area have a data format with header information.

FIG. 9 is a diagram showing a conventional servo frame, and is a data configuration diagram of a servo frame in which only track position information is recorded in a gray code area.

FIG. 10 is a data configuration diagram used to describe the count of a servo area in a servo frame.

FIG. 11 is a circuit diagram showing a counter for counting a servo area in a servo frame.

FIG. 12 is a data configuration diagram used for describing reading of an index pulse and counting of servo frames.

FIG. 13 is a circuit diagram of a counter that counts a servo area and detects a servo frame position using an index pulse as a clear signal.

[Explanation of symbols]

1 disk, 50 disk reproducing device, 63 digital operation processing circuit, 66 tracking error detection circuit, BL block, FL identification flag, GE gray code area, SCI circumferential position information

Claims (8)

[Claims] 1. A gray code area having a servo area in which a servo pattern signal is recorded for each servo frame obtained by dividing a recording track, and in which a gray code corresponding to track position information in the servo area is recorded. A recording medium having circumferential position information therein. 2. The recording medium according to claim 1, wherein said circumferential position information is recorded in said gray code area together with said track position information. 3. The recording medium according to claim 1, wherein identification information for identifying said circumferential position information is recorded in said gray code area. 4. A signal reproducing apparatus for reproducing a recording medium in which a recording track is divided for each servo frame and a gray area corresponding to track position information is recorded in a servo area in the servo frame. A tracking error detection unit for performing a tracking error signal; and performing on-track based on the tracking error signal detected by the tracking error detection unit, and then determining circumferential position information recorded in the gray code area. A signal reproducing device comprising: circumferential position information discriminating means. 5. The signal reproducing apparatus according to claim 4, wherein said tracking error detecting means detects said tracking error signal based on a servo pattern signal recorded in a servo area in said servo frame. . 6. The signal reproducing apparatus according to claim 4, wherein a servo frame number is obtained based on the circumferential position information determined by the circumferential position information determining means. 7. A system according to claim 1, further comprising a sector position judging unit for judging a position of the sector, wherein a sector on which desired data is recorded is accessed based on the judgment information obtained by said sector position judging unit. 5. The signal reproducing device according to 4. 8. A signal reproducing method for reproducing a recording medium having a gray code area in which a recording track is divided for each servo frame and a gray code corresponding to track position information is recorded in a servo area in the servo frame. A tracking error detection step of detecting a tracking error signal by a tracking error detection means; and a circumferential direction recorded in the gray code area after on-tracking based on the tracking error signal detected in the tracking error detection step. A circumferential direction position information determining step of determining the position information.