Browse Prior Art Database

Write Date Circuits with Sample Sector Servo

IP.com Disclosure Number: IPCOM000122468D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Narisawa, S: AUTHOR

Abstract

Described herein is a technique for improving data quality on a Disk Drive with the use of a sample sector servo. The advantage of this technique is to simplify spindle motor drive circuits and to gain synchronized data with motor rotation speed.

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Write Date Circuits with Sample Sector Servo

      Described herein is a technique for improving data
quality on a Disk Drive with the use of a sample sector servo. The
advantage of this technique is to simplify spindle motor drive
circuits and to gain synchronized data with motor rotation speed.

      The technique uses a sample sector servo system for
synchronizing the clock from the sector servo with the clock of the
write data string. Normally, the disk drive has a sector servo as
shown in Fig.  1, especially on the low-end disk drive units.  This
servo pattern is used to pick up track information and clock
information which synchronize disk surface rotation.

      This technique employs the circuits shown in Fig. 2. The
portion encircled with a dotted line is a normal PLL (Phase-Locked

Loop

) circuit except for a write switch, as shown in the center of
Fig. 2. The write switch is closed in case of normal read operation,
and the circuits generate synchronized clock with disk surface
rotations. In case of write operation, this switch is closed until
the desired ID portions are located, and then the write switch is
opened at this time.  Disk surface rotation speed can not vary within
some units of millisecond because of mechanical operations,
therefore, when the write switch is open, this PLL circuit still
generates the synchronized clock with disk surface rotation. Then,
the write data string is modulated with this clock and written on the
disk surface. T...