JPS62250567A - Medium eccentricity correcting device - Google Patents

Abstract

PURPOSE:To decrease the position deviation as the entire data string by detecting servo information recorded on a track of a medium and dividing the difference of servo information of the outer and inner circumferential sides by the sum so as to correct the position deviation. CONSTITUTION:The titled device is so constituted that the servo information recorded on the track of the medium 1 is detected and the difference of the servo information for the outer and inner circumferential sides is divided by the sum to correct the position deviation. Thus, the magnetic head is not merely arranged to the frontmost position of the data, but the position deviation as the entire data string is reduced. That is, let a peak hold value of an A pattern 22a quantized by an A/D conversion circuit 21 be 'A' and a value of a peak hold value of a B pattern 22b quantized by the circuit 21 be 'B', then the head position deviation DELTAS is calculated as DELTAS=K(A-B)/(A+B). The head actuator control parameter is calculated to move the head actuator 14, then a head 12 is moved and the S/N is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a media eccentricity correction device used in a sector servo type floppy disk drive (FDD) device or the like.

Prior Art FIG. 4 is a front view of a general floppy disk (media). In FIG. 4, ``■'' is a medium, and this medium 1 has a hole 2 in the center and a large number of magnetically recordable and reproducible tracks 3 between the hole 2 and the outer periphery. The drive device inserts a conical stopper into this hole 2 and inserts the media 1.
is rotating.

By the way, when the stopper is inserted into the hole 2, an error 6 occurs when installing it at the center, so an error 7 on the track occurs. Since these errors 6.7 are usually about 15 microns, they affect media with a normal track pitch of 132 microns, and unless some countermeasure is taken, reading errors will occur.

FIG. 5 is a front view showing a correction method of a conventional media eccentricity correction device. In current sector servo type FDD devices, the head position deviation is corrected based on the servo position deviation information of the currently passed sector, so media IK recording and playback are performed with the trajectory shown in Figure 5. Become.

Problems to be Solved by the Invention However, in the above-mentioned conventional media eccentricity correction device,
As shown in FIG. 5, there is a positional deviation Δr from the center of the media between each sector due to the eccentricity of the media.

If the initial positional deviation of the data area is ΔS, then the positional deviation ΔS1 of the final part of the data area is ΔSI=ΔS, +Δr.Because of the positional deviation Δr from the center, the area of the shaded part () is large. As a result, the SZN ratio of the readout amplifier deteriorates, and the probability of error occurrence increases. Further, there is a problem in that the larger the eccentricity of the media, the larger the positional deviation Δr from the center, which further deteriorates the S/N ratio.

Means for Solving the Problems In order to solve the above problems, the present invention detects the servo information recorded on the track of the media and divides the difference in the servo information on the outer circumference side and the inner circumference side by the sum. It is configured to correct positional deviation.

Effect of the Invention With the above-described structure, the present invention does not simply align the magnetic head with the front row of data, but also reduces the amount of misalignment of the data row as a whole.

Embodiment FIG. 1 is a block diagram of a media eccentricity correction device according to the present invention, and FIG. 2 is an explanatory diagram of the operation of the same embodiment.

In Figures 1 and 2, 1 is the servo format 22
a, 22b and data 23 can be recorded on tracks; 11 is a spindle motor for rotating the medium 1; 12 is a magnetic head for recording and reproducing information on the medium 1; 13 is a carriage for supporting the magnetic head 12; This is a head actuator that moves this carriage 13 onto a desired track. 17 is a bit pattern detection circuit that converts an analog signal detected by the magnetic head 12 into a pulse signal, and 18 is a servo detection circuit that detects servo formats 22a and 22b from the bit pattern.

19 is a preamplifier circuit that amplifies the signal from the magnetic head 12 as an analog signal; 20 is a servo format based on the signal from the servo detection circuit 18; 22 is a peak hold circuit that detects the peak values of a and 22b; 21 is a peak hold circuit 20 This is an A/D conversion circuit that converts the signal into a digital value. Reference numeral 16 denotes a control means. This control means 16 reads the data 23 recorded on the medium 1 from the signal of the A/D conversion circuit 21, and reads the data 23 recorded on the medium 1 from the signal of the servo detection circuit 18. Chieta circuit 14
Through this, the head 12 can be moved slightly.

Next, the operation of this embodiment will be explained.

1 and 2, the output (+i
+to,,, l,-/n%1lth&8FhihB/
A, w IEI FI6L15, the carriage 13 is moved via the head actuator circuit 14, and the magnetic head 12 is moved onto a desired track on the medium l. The magnetic head 12 detects signals on tracks from the medium 1 being rotated by the spindle motor 11 . The output of the magnetic head 12 is sent to the bit pattern detection circuit 1.
7 becomes a pulse waveform, in which the servo format)
22 a.

22b only is detected by the servo detection circuit 18 and the control means 1
Output to 6.

On the other hand, the preamplifier circuit 19 input from the magnetic head 12
The output of is obtained by inputting the signal from the servo detection circuit 18.
The peak hold of only the servo formats 22a and 22b is performed, and the control means 1 is processed via the A/D conversion circuit 21.
6. After predetermined calculation, the control means 16 controls D/
The magnetic head 12 is slightly moved on the track via the A conversion circuit 15 and the head actuator circuit 14 to correct the eccentricity of the medium.

Next, a method of controlling the control means 16 will be explained. In FIG. 2, the peak hold value of the A pattern 22a is quantized by the A/D conversion circuit 21 as "A", and the value of the B pattern 22a is quantized by the A/D conversion circuit 21.
When the value obtained by quantizing the peak hold value of 2b by the A/D conversion circuit 21 is rBJ, the head position deviation amount ΔS
is calculated as

In addition, the position control of the step motor 11 is 196TPi (
For media with 196 tracks per inch, the track pitch is 132 microns, so the output current of the human phase is: B-phase output current IFH. However, Xn is a position control parameter obtained by dividing one track into 132, and IK is a current constant that varies depending on the motor. Since 1 degree of Xn corresponds to 1 micron, 0<Xn<132. Parameter X during head position control. becomes. However, C is a variable that differs depending on the number of phases, and α is a correction value associated with motor hysteresis.

Head position control is performed using the method described above.

In the servo system, the eccentricity of the medium is recorded in the storage means (RAM) of the control means 16 in the form of one period or several periods of the medium.

In actual control, becomes. β is a constant that varies depending on the phase and motor.

The first term in parentheses is the media eccentricity of the next sector on the RAM, and the second term is the media eccentricity of the current sector on the RAM. is the added value of

The head actuator control parameters are calculated based on the value of Xn+1, and the bed actuator 14 is
move. In this embodiment, the head 12 moves as shown in FIG. 2, the area of the shaded area in FIG. 2 decreases, and the S/N ratio improves. That is, by controlling the head position so that the value of ΔSo+ΔS1 is minimized, the area of the shaded portion can be reduced.

Furthermore, in the second embodiment, reading of the eccentricity of the media and calculation of the actuator control parameters are performed in the same manner as in the first embodiment, and the variation amounts of the actuator control parameters are xn+, -x.

is output in several stages. In this case, the head follows a trajectory as shown in FIG. The shaded area in FIG. 3 is reduced, and the S/N ratio is improved compared to the first embodiment.

Furthermore, as a third embodiment, in the second embodiment,
By interpolating between n+1 and Xn using a sine wave or the like, it is possible to further reduce the deviation between the actual data area and the head position trajectory.
/N ratio can be improved.

Effects of the Invention As is clear from the above embodiment, the present invention detects the servo information recorded on the track of the media, and corrects the positional deviation by dividing the difference between the servo information on the outer circumference side and the inner circumference side by the sum. This configuration has the effect that the amount of positional deviation of the data string as a whole can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a media eccentricity correction device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the same embodiment, FIG. The figure is a front view of a general media, and FIG. 5 is an explanatory diagram of the operation of a conventional example. 1... Media, 11... Spindle motor, 12
...°Magnetic head, 13... Carriage, 14...
Head actuator circuit, 15...D/A conversion circuit, 16...Control means, 17...Hit haturn detection circuit, 18...Servo detection circuit, 19...Preamplifier circuit, 20...Peak Hold circuit, 21...A
/D conversion circuit. Name of agent: Patent attorney Satoshi Nakao and 1 other person No. 1
Figure M2 Figure

Claims (1)

[Claims] A medium on which servo information provided on the outer circumferential side and an inner circumferential side of the track center line and data provided with the track center line as the center are magnetically recorded, and the medium is rotated. a servo detection circuit that inputs the signal of this magnetic head and detects the servo information; and a servo detection circuit that inputs the signal of the magnetic head and detects the servo information. A peak hold circuit holds the maximum value of this input signal only when the signal of this peak hold circuit is input, and the head position deviation amount S
, S={(A-B)/(A+B)}×K However, A: Voltage value of servo information on the outer circumference side B: Voltage value of servo information on the inner circumference side K: Calculated using the proportionality constant, and the above A media eccentricity correction device comprising a control means for correcting the position of a magnetic head.