JP2790570B2 - Disk recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk recording / reproducing apparatus using a method of accessing a desired track by performing a coarse access and a fine access when accessing a track on a recording medium. It is.

[0002]

2. Description of the Related Art Generally, an access operation to a disk-shaped recording medium having concentric or spiral tracks first moves to a vicinity of a target track by coarse access, and then accesses the target track by fine access. The method has been done. The control of the coarse access operation is designed based on the general characteristics of the device. For example, as shown in FIG. 3, only the distance between the start track 21 and the target track 22 is always given to the control means 24 for controlling a control target 25 such as a driving means for driving an optical head (not shown). Have been. That is, the start track 21 and the target track 22 are calculated by the subtractor 23, and the difference between them, that is, the distance represented by the number, is calculated by the control unit 24.
Is input to The control means 24 controls the control target 25 based on the distance.

[0003]

However, even when the coarse access operation is controlled as designed on average, errors occur in each coarse access operation due to differences in directions and places. . Therefore, there is a problem that this error must be processed in the subsequent fine access operation.

An object of the present invention is to improve the accuracy and access time of the coarse access operation by correcting the coarse access operation to eliminate the error and updating the correction value based on the reached track. It is an object of the present invention to provide a disk recording / reproducing apparatus capable of performing the above.

[0005]

According to the present invention, there is provided a disk recording / reproducing apparatus for coarsely accessing a disk-shaped recording medium having radially formed concentric or spiral tracks. In a disk recording / reproducing apparatus that accesses a desired track by performing fine access after performing the above, the correction value of the access distance corresponds to the value of the start track and the value of the target track.
Storage means that is attached and stored; reference means for reading a corresponding correction value from the input start track and target track values from the storage means; and a read correction value and a coarser value than the start track and target track values. Calculating means for calculating the output value of the access, calculating a new correction value based on the difference between the value of the track reached by the output value and the value of the target track, and storing the new correction value in the storage means And registration means.

In the above-mentioned calculating means, it is preferable that the new correction value is calculated by the following equation: correction value + (target track−arrival track) × coefficient (where 0 <coefficient ≦ 1).

[0007]

With the above arrangement, the corresponding correction value stored in the storage means is output from the values of the start track and the target track at the time of coarse access, and coarse access is performed based on the value corrected by this correction value. It is. Furthermore, from the difference between the track reached by coarse access and the target track,
A new correction value is calculated by the calculation means and stored in the storage means by the registration means. At this time, a new correction value is stored in place of the previous correction value. Therefore, when the same start track and target track values are input next, coarse access is performed based on the values corrected by the new correction values. Then, a new correction value is calculated and stored from the difference between the reached track and the target track. Similarly, the correction value is updated each time coarse access is performed, and the reached track converges on the target track.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the disc recording / reproducing apparatus of the present invention calculates a group _{Y.sub.j based} on the value of the target track 2 and a group _{X.sub.i based} on the value of the start track 1. And a group X operation means 4. Here, the group is a group of a plurality of tracks. For example, when the start track is divided into groups of 10 tracks from 0 track, 4 tracks are group X ₀ and 18 tracks are group X ₁ .

The group X operation means 4 and the group Y
The output from the calculation means 5 is input to a table reference means 6 which is a reference means. Table reference unit 6 reads the correction value of the corresponding (X _i, Y _j) in the correction table 9 is X _i, the storage means from the Y _j input.

The read correction value is input to an arithmetic circuit 8 which is arithmetic means described later. On the other hand, target track 2
And the value of the start track 1 are input to the arithmetic circuit 8, and the arithmetic circuit 8 corrects the access distance (the number of seeks) to the target track by the correction value, and then outputs the result to the control means 11.

The control means 11 controls the control target 12 so as to move in accordance with the obtained number of seeks, and inputs the value of the actually reached track 3 to the arithmetic circuit 8. The arithmetic circuit 8 calculates a difference (error) from the target track 2 from the input value of the arrival track 3 and calculates a new correction value from the error by the following equation. New correction value = correction value + (target track−arrival track) × (1 / n) (where 1 ≦ n) The obtained new correction value is input to the table registration means 7.

The table registration means 7 writes a new correction value into the corresponding (X _i, Y _j ) of the correction table 9. When the power of the apparatus is turned off, all the correction values in the correction table 9 are deleted.
Next, when the coarse access operation is performed for the first time, there is no data to be corrected, so that the correction values of the correction table 9 are all initialized by the table initializing means 10 when the apparatus is powered on.

The arithmetic circuit 8 receives the values of the start track 1 and the target track 2 and outputs the difference between them. The subtracter 14 outputs the difference between the values, and adds the output of the subtracter 14 and the correction value from the table reference means 6. Adder 15, a subtractor 16 to which the value of the reaching track 3 and the value of the target track 2 are input and subtracted, and a coefficient (1 / n) added to the output from the subtractor 16.
And an adder 1 for adding the output from the 1 / n circuit 13 to the correction value from the table reference means 6
7.

In the above configuration, the coarse access operation is performed as shown in FIG.
This will be described below with reference to FIG.

First, a group X is calculated by the group X calculating means 4 from the value of the start track 1 (S).
1). On the other hand, the group Y is calculated by the group Y calculating means 5 from the value of the target track 2 (S2).

The table reference means 6 reads out the corresponding correction value in the correction table 9 in accordance with the value of the calculated X _i and Y _j (S3).

In the arithmetic circuit 8, the correction value obtained in S3 is added to the difference between the value of the target track 2 and the value of the start track 1, that is, the access distance (the number of tracks) to obtain a corrected access distance ( S4).

The control means 12 controls the controlled object 12 so as to perform a seek based on the corrected access distance (S5).

The arithmetic circuit 8 calculates the difference between the value of the track 3 reached as a result of the seek and the value of the target track 2 by a coefficient 1
/ N is multiplied, and the result is added to the correction value obtained in S4 to calculate a new correction value (S6).

The table registration means 7 registers a new correction value in the corresponding (X _i , Y _j ) of the correction table 9 (S7).

By repeating the above steps, the correction value is updated, and the value of the reaching track 3 converges to the value of the target track 2.

If the value of n is small, that is, if 1 / n is large, the value converges to the value of the reached track 3 more quickly.
If 1 / n is small, the error is also multiplied by 1 / n, so that when the arrival track is affected by disturbance or servo deviation, the influence can be further reduced. Therefore, the value of n may be set to an appropriate value depending on whether the correction value is focused on the convergence rate or whether the correction value is strong against disturbance.

Next, the above operation will be described using specific values. For example, in the case of rough access from track 0 to track 1000, it is assumed that the disk recording / reproducing apparatus has a characteristic of accessing the specified distance by 10% less than the specified distance, and n is 2. .

In the first access, since the correction value = the initial value, that is, 0 tracks, a seek distance of 1000 tracks is specified for the target track value of 1000, and the reached track value is 900. Then, the difference between the target track and the reached track, 100 lines are multiplied by a factor of 1/2, and then added to the correction value, and the new correction value becomes 50 lines.

In the second access, since the correction value is 50, a seek distance of 1050 is specified for the target track value of 1000. As a result, the value of the reaching track becomes 945, and the difference between the target track and the reaching track, 5
The calculation is performed on five lines, and the new correction value becomes 77 lines.

Similarly, in the third access, a seek distance of 1077 is specified, and the value of the reached track is 970. The new correction value is 92.

As described above, by repeatedly performing the coarse access, the correction value is updated so that the value of the target track and the value of the reached track become closer.

Therefore, when performing coarse access in the disk recording / reproducing apparatus of the present invention, the access distance to the target track is corrected by the correction value. Further, since this correction value is updated by repeating coarse access, the device has a function of learning a correction value for the influence of a temperature change or the like accompanying use of the device.

By performing such coarse access repeatedly, the coarse access is corrected and learned so as to converge on the target track. Further, even when an abnormal error occurs due to a disturbance or the like, the effect can be suppressed by the coefficient n.

[0031]

As described above, according to the disk recording / reproducing apparatus of the present invention, the correction value for the access distance is
Storage means value and associated with the value of the target track is stored, and reference means for reading from the storage means a correction value corresponding the value of the start track and the target track is input, the correction value and the start read Calculating means for calculating a coarse access output value from the value of the track and the target track, and calculating a new correction value based on the difference between the value of the track reached by the output value and the value of the target track; A registration unit for storing the correction value in the storage unit.

In the calculating means, a new correction value is calculated by an equation represented by a new correction value = correction value + (target track−arrival track) × coefficient (where 0 <coefficient ≦ 1). Is done.

Therefore, the accuracy of the access to the target track is improved by the correction value when performing the coarse access. Further, since the correction value is updated so as to be closer to the target track by repeating the coarse access, the accuracy is further improved. As a result, more precise correction corresponding to the difference in direction, location, and the like can be performed, and an effect that a stable coarse access operation can be performed is achieved. Further, by setting an appropriate coefficient value in the calculation of the correction value, the effect that even if an abnormal error occurs due to disturbance or the like can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a disk recording / reproducing apparatus according to the present invention.

FIG. 2 is a flowchart illustrating a coarse access performed in the disk recording / reproducing apparatus of the present invention.

FIG. 3 is a block diagram showing a configuration of a main part of a conventional disk recording / reproducing apparatus.

[Explanation of symbols]

 Reference Signs List 1 start track 2 target track 3 arrival track 6 table reference means (reference means) 7 table registration means (registration means) 8 arithmetic circuit (calculation means) 9 correction table (storage means)

Claims (2)

(57) [Claims] A disk recording / reproducing apparatus for accessing a desired track by performing a coarse access and then a fine access to a disk-shaped recording medium on which concentric or spiral tracks are formed in a radial direction. Access distance correction value is the start track value and target
Storage means stored in association with the value of the track, a reference means for the correction value read from the storage means from the corresponding values of the start track and the target track entered, the read correction values and the start track and the target Calculating means for calculating an output value of the coarse access from the value of the track, and calculating a new correction value based on a difference between a value of the track reached by the output value and a value of the target track; A disk recording / reproducing apparatus, comprising: a registration unit for storing in a storage unit. 2. The arithmetic means according to claim 1, wherein a new correction value = correction value + (target track−arrival track) × coefficient (where,
2. The disk recording / reproducing apparatus according to claim 1, wherein a new correction value is calculated by an equation represented by 0 <coefficient ≦ 1).