JPH03228264A - Magnetic disk driver - Google Patents

Abstract

PURPOSE:To increase the information recording capacity by recording the information synchronously with the position detecting signal of a rotary encoder attached to a drive motor of a magnetic disk. CONSTITUTION:A magnetic disk 1 held by a magnetic head 4 is revolved by a spindle motor 2 for recording and reproducing the information. A rotary encoder 3 is attached to the motor 2, and a frequency N-multiple circuit 8 produces a reference clock f1 for data recording from the pulse signal produced from a pulse production circuit 7 synchronously with the revolution of the motor 2. At the same time, the recording data is synchronized with the clock f1 via a recording circuit 9 and recorded to the disk 1. If the motor 2 has a revolving fluctuation, the frequency of the clock f1 also varies synchronously with the revolving fluctuation of the motor 2. Thus the recording position has no fluctuation on the disk 1. Then the recording capacity of information is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk drive device, and more particularly to an improvement in its recording method.

[Conventional technology]

In conventional devices of this type, when recording information, the position where the information is recorded on the disk changes if the rotation of the motor changes.

As a countermeasure for this problem, there are two methods: one is to use a motor with small rotational fluctuations, and the other is to provide a margin in the format for recording information on the disk to absorb the rotational fluctuations.

[Problems to be Solved by the Invention] However, the former method increases the cost of the magnetic disk drive device, and the latter method reduces the amount of information that can be recorded on each magnetic disk.

Furthermore, in devices that use sector servo, information may be overwritten on the servo signal due to motor rotational fluctuations, thereby destroying the servo signal.

The present invention solves the disadvantage of the conventional product described above, which is the reduction in recording capacity due to fluctuations in motor rotation, and thereby provides a large-capacity magnetic disk drive device. In a magnetic disk drive device that records and reproduces information by rotationally driving the magnetic disk, this is achieved by recording information in synchronization with a position detection signal from a rotary encoder attached to a drive motor for the magnetic disk.

[Effect]

For use in controlling the speed of the motor, the position sensing signal of a rotary encoder attached to the motor is synchronized with the rotation of the motor. Then, PLL this signal
A circuit using a phase-locked loop (phase-locked loop) etc. is used to create a standard clock for information recording at an appropriate frequency.

This reference clock is synchronized with the rotation of the motor, so
Even if there is a change in motor rotation, the position where information is recorded on the disk does not change.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The figure is a control block diagram of a magnetic disk drive device according to an embodiment of the present invention.

In this apparatus, a magnetic disk 1 held between magnetic heads 4 is rotationally driven by a spindle motor 2 to record and reproduce information. The magnetic head 4 is attached to a carriage 5 and can be moved to a predetermined position by a stepping motor 6.

A rotary encoder 3 is attached to the spindle motor 2, and m pulses per rotation of the motor are generated in a pulsing circuit 7 in synchronization with the rotation of the motor. PLL this pulse signal (phase lock loop)
A reference clock f for data recording is created using a frequency N-multiplying circuit 8 using, for example.

On the other hand, recording data is synchronized with the reference clock f using the recording circuit 9 and recorded on the magnetic disk 4 through the head amplifier 10.

When there is a rotational fluctuation in the spindle motor 2, the period of the reference clock f1 changes in synchronization with the rotational fluctuation.
The position recorded on the magnetic disk 1 does not change.

The table below shows the results of measuring the amount of variation in the data recording position when data is recorded on a magnetic disk using the same spindle motor for the apparatus of the present invention and the conventional apparatus. The spindle motor used had a steady speed deviation of ±0.4%, an instantaneous speed fluctuation of ±2.0%, and an instantaneous period fluctuation of ±0.05%, and was rotated at 360 rpm.

Table [Effects of the Invention] As explained above, according to the present invention, information is recorded in synchronization with the position detection signal of the rotary encoder attached to the drive motor. The margin for absorbing fluctuations in the information recording position can be reduced. As a result, it is possible to increase the information recording capacity.

[Brief explanation of drawings]

The figure is a control block diagram of a magnetic disk drive device according to an embodiment of the present invention. 1...Magnetic disk, 2...Spindle motor,
3... Rotary encoder, 4... Magnetic head.

Claims (1)

[Claims] In a magnetic disk drive device that records and reproduces information by rotationally driving a magnetic disk held between magnetic heads, recording of information is synchronized with a position detection signal from a rotary encoder attached to a drive motor for the magnetic disk. What is claimed is: 1. A magnetic disk drive device characterized in that: