JPH07182676A - Apparatus for correcting eccentricity of disc medium - Google Patents

Abstract

PURPOSE:To eliminate influences of outer disturbances when an eccentricity is detected and to correctly correct the eccentricity by adding an operating circuit and a storing circuit for storing an eccentricity correction value. CONSTITUTION:A first memory circuit 6 stores the output of eccentricity data from an up-down counter 5, and an operating circuit 7 operates and generates an eccentricity correction value from the content of the first memory circuit 6 by approximating a sine wave of the same cycle as the rotation of a disc medium 1. A second memory circuit 8 is a circuit for storing the eccentricity correction value generated at the operating circuit 7. A control circuit 12 controls the up-down counter 5, the operating circuit 7 and a D/A converter circuit 9 upon receipt of a signal 18 of rotary position data from a rotary position data-generating circuit 11. An eccentricity correction signal of the sine wave of the same cycle as the rotation of the disc medium 1 is output based on the eccentricity correction value stored in the second memory circuit 8 to a head 2 thereby to correct the eccentricity. Accordingly, influences of outer disturbances when the eccentricity is detected are eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording / reproducing information on / from a disk medium having an information track by a head and for correcting the eccentricity of the disk medium.

[0002]

2. Description of the Related Art In recent years, in tracking control of a head of a disk medium, eccentricity correction for canceling the eccentricity caused by the eccentricity of the disk medium itself or the center deviation when the disk medium is installed in a rotating system has come to be performed. .

A conventional eccentricity correction device for a disk medium will be described below.

FIG. 3 is a block diagram showing the structure of a conventional disk medium eccentricity correction device. In FIG. 3, reference numeral 1 is a disk medium, and 2 is a head for reading information from an information track of the disk medium 1 and detecting a track error signal. A spindle motor 3 rotates the disk medium 1. A waveform shaping circuit 4 shapes the track error signal from the head 2 into a rectangular wave. An up / down counter 5 counts the number of lines crossing the information track.
A storage circuit 19 stores the output of the up / down counter 5. A D / A conversion circuit 20 converts the digital output of the storage circuit 19 into an analog output. 10 is a driver, D / A
The head 2 is driven by the output signal of the conversion circuit 20. Reference numeral 11 denotes a rotational position information generation circuit, which outputs information on the rotational position of the disk medium 1. A control circuit 21 receives the rotational position information signal from the rotational position information generating circuit 11 and controls the up / down counter 5, the storage circuit 19, and the D / A conversion circuit 20.

The operation of the eccentricity correction device for a disk medium having the above-described structure will be described below with reference to FIG. 4 showing the waveform of each part of FIG. When the eccentric displacement amount of the disk medium 1 is in the state shown by the curve 22 shown in FIG. 4A, the track error signal 23 shown in FIG. 4B is output unless the track servo control is applied. This is shaped into a rectangular wave by the waveform shaping circuit 4, and the track error shaping signal 24 shown in FIG. 4 (c) is obtained. This track error shaping signal 24
Since the eccentricity can be quantified by counting up and down with the up / down counter 5, the content of the up / down counter 5 is referenced from the rotation position information generation circuit 11 to the rotation position information signal 26 (Fig. 4 (e)). Then, the control circuit 21 can obtain the eccentricity information for one round of the disk.

Next, from the up-down counter 5 to the memory circuit
The operation of storing in 19 is stopped, the contents of the storage circuit 19 are sequentially read out for one rotation of the disk with reference to the rotational position information signal 26, and converted into analog by the D / A conversion circuit 20. A D / A converted signal 25 shown in FIG. 4 (d) is obtained. Driver with this D / A conversion signal 25
The eccentricity is corrected by driving the head 2 at 10.

[0007]

However, in the above-mentioned conventional configuration, when there is a disturbance such as external vibration when detecting the eccentricity state, the eccentricity information is stored in a state including the disturbance. Therefore, if the eccentricity correction is performed based on the eccentricity information including the disturbance, the eccentricity correction cannot be performed accurately.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an eccentricity correction device for a disk medium which eliminates the influence of disturbance at the time of detecting an eccentricity state.

[0009]

To achieve this object, an eccentricity correction device of the present invention provides a waveform shaping circuit for shaping a track error signal into a rectangular wave and a track error signal shaped by the waveform shaping circuit. An up / down counter that counts and outputs eccentricity information, a rotation position information generation circuit that outputs a rotation position information signal indicating a rotation position of the disk medium, and a rotation position information signal of the rotation position information generation circuit as a reference. An eccentricity information storage circuit that stores the contents of the up / down counter at a plurality of points around the circumference of the disk medium, and the eccentricity information stored in the eccentricity information storage circuit is approximated to a sine wave having the same cycle as the rotation cycle of the disk medium. And an eccentricity correction value storage circuit for storing the eccentricity correction value calculated by the arithmetic circuit. Sequentially analog conversion on the basis of the said rotation position information signal from the eccentricity correction value stored in the D / A
A conversion circuit, a driver for driving the head by the output signal of the D / A conversion circuit, and an operation of the up / down counter, the arithmetic circuit, and the D / A conversion circuit based on the rotation position information from the rotation position information generation circuit. A control circuit for controlling is provided, and the detected eccentricity information is approximated by a sine wave having the same cycle as the rotation cycle of the disk medium, and the eccentricity is corrected by this sine wave.

[0010]

According to the present invention, the eccentricity component of the disk medium has almost no component due to the deviation of the information track from the true circle, and most of the component due to the deviation between the center of the information track and the center of rotation of the disk medium. Can be approximated, so
With this configuration, even when there is a disturbance such as vibration from the outside when detecting the eccentricity state, the eccentricity state is detected by approximating the eccentricity state with a sine wave having the same cycle as the rotation cycle of the disk medium. Eccentricity correction that is not affected by disturbance can be performed.

[0011]

1 is a block diagram showing the configuration of an eccentricity correction device for a disk medium according to an embodiment of the present invention. Figure 1
In the above, reference numeral 6 denotes a first storage circuit, which stores the eccentricity information output of the up / down counter 5, and is referred to as an eccentricity information storage circuit. The arithmetic circuit 7 performs an arithmetic operation from the contents of the first storage circuit 6 and generates an eccentricity correction value (digital data) by approximating a sine wave having the same cycle as the rotation of the disk medium 1.
A second storage circuit 8 stores an eccentricity correction value approximated to the sine wave generated by the arithmetic circuit 7, and is referred to as an eccentricity correction value storage circuit. The control circuit 12 receives the rotational position information signal 18 from the rotational position information generation circuit 11 and controls the up / down counter 5, the arithmetic circuit 7, and the D / A conversion circuit 9. The same components as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

The operation of the eccentricity correction device for a disk medium configured as described above will be described below.
When the eccentric displacement amount of the disk medium 1 is in the state shown by the curve 13 shown in FIG. 2A, the track error signal 14 shown in FIG. 2B is output unless the track servo control is applied. This is shaped into a rectangular wave by the waveform shaping circuit 4 and is shown in FIG.
By counting with the track error shaping signal 15 shown in (c), the eccentricity state can be quantified as the up / down counter output 16 shown in FIG. 2 (d). With reference to the rotational position information signal 18 from the rotational position generation circuit 11 shown in FIG.
By storing in the (eccentricity information storage circuit), the eccentricity information for one rotation can be obtained.

Next, the operation of storing data from the up / down counter 5 in the first storage circuit 6 is stopped, and the first storage circuit 6 is stopped.
The arithmetic circuit 7 approximates the eccentricity information of a plurality of points of the disk medium 1 stored in the above with a sine wave having the same cycle as the rotation cycle of the disk medium 1 by using an approximation method such as the least square method. The resulting eccentricity correction value is stored in the second storage circuit 8 (eccentricity correction value storage circuit). The eccentricity correction signal is obtained by sequentially reading the contents of the second storage circuit 8 for one rotation of the disk medium 1 with the rotational position information signal 18 as a reference and converting the contents into an analog signal by the D / A conversion circuit 9. A D / A converted signal 17 shown in 2 (e) is obtained. This D
The eccentricity correction is performed by driving the head 2 with the driver 10 by the / A conversion signal 17.

When the track error shaping signal 15 is counted by the up / down counter 5, the track error shaping signal 15 may always be counted up or down, and based on the data, the arithmetic circuit 7 may approximate a sine wave. However, a reproduction signal from the head 2 (Japanese Patent Laid-Open No. 57-924
42) and track sum signal (JP-A-63-281006)
The eccentricity information may be fetched by detecting the direction crossing the information track based on the above, and controlling the count-up and count-down of the up / down counter 5.

[0015]

As described above, in the disk medium eccentricity correction apparatus of the present invention, most of the eccentricity components of the disk medium are due to the deviation from the true circle of the information track.
Since it can be approximated by a sine wave, by approximating the eccentricity information by a sine wave having the same cycle as the rotation cycle of the disk medium, it is possible to eliminate the influence of disturbance when the eccentricity information is detected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an eccentricity correction device for a disk medium according to an embodiment of the present invention.

FIG. 2 is a waveform diagram of each part of the eccentricity correction device for a disk medium in FIG.

FIG. 3 is a block diagram showing a configuration of an eccentricity correction device for a disk medium in a conventional example.

FIG. 4 is a waveform diagram of each part of the eccentricity correction device for a disk medium in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disk medium, 2 ... Head, 3 ... Spindle motor, 4 ... Waveform shaping circuit, 5 ... Up-down counter, 6 ... 1st memory circuit (eccentricity information memory circuit), 7 ... Arithmetic circuit, 8 ... 2nd Memory circuit (eccentricity correction value memory circuit),
9 ... D / A conversion circuit, 10 ... Driver, 11 ... Rotation position information generation circuit, 12 ... Control circuit, 13 ... Eccentric displacement amount,
14 ... Track error signal, 15 ... Track error shaping signal, 16 ... Up / down counter output, 17 ... D / A
Conversion signal, 18 ... Rotation position information signal.

Claims (1)

[Claims] 1. An apparatus for recording / reproducing information on / from a disk medium having an information track by a head, wherein a waveform shaping circuit for shaping a track error signal and a signal shaped by the waveform shaping circuit are counted to obtain eccentricity information. An up / down counter for outputting, a rotation position information generating circuit for outputting a rotation position information signal indicating a rotation position of the disk medium, and a plurality of one rotations of the disk medium with reference to the rotation position information signal of the rotation position information generating circuit. The eccentricity information storage circuit that stores the output of the up / down counter at the point of (4) The calculation circuit to be generated, the eccentricity correction value storage circuit that stores the eccentricity correction value calculated by the calculation circuit, and the eccentricity correction value storage circuit A D / A conversion circuit that sequentially performs analog conversion based on the stored eccentricity correction value based on the rotational position information, a driver that drives the head by the output signal of the D / A conversion circuit, and a rotation from the rotational position information generation circuit. An eccentricity correction device for a disk medium, comprising: an up / down counter, a control circuit for controlling the operation of the arithmetic circuit, and a D / A conversion circuit based on position information.