Browse Prior Art Database

Servo-Burst Pattern Read by Write Element

IP.com Disclosure Number: IPCOM000116483D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Nakamura, T: AUTHOR [+3]

Abstract

Disclosed is methodology to improve the linearity of the Position Error Signal (PES) in the Hard Disk Drive (HDD) which uses the Magneto Resistive/Inductive (MRI) head. The linearity of PES can be improved by reading the servo-burst signal with the Inductive element, not with the Magneto Resistive (MR) element.

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Servo-Burst Pattern Read by Write Element

      Disclosed is methodology to improve the linearity of the
Position Error Signal (PES) in the Hard Disk Drive (HDD) which uses
the Magneto Resistive/Inductive (MRI) head.  The linearity of PES can
be improved by reading the servo-burst signal with the Inductive
element, not with the Magneto Resistive (MR) element.

      The MRI head has MR element which is used for read operation
and the Inductive element which is used for write operation.  It is
normally designed that the width of the MR element becomes a half of
the track width to prevent noise from adjacent tracks, because it is
used for read operation.  It is also designed so the width of the
Inductive head is wider than half of the track width to write data
into the disk with enough width.

      In case that the PES is calculated with 4 servo-burst patterns
shown in the Figure, if the width of the MR element is narrower than
a half of the track width due to a tolerance, the area in which the
input signal amplitude at each burst pattern does not change will
appear around a quarter of a track width apart from the track center.
Such area degrades the linearity of the PES characteristic.

      On the other hand, the asymmetry of sensitivity in the MR
element will also degrade the linearity of the PES characteristic.

      This disclosure provides an economical method to improve the
linearity of the PES characteristic by reading only the servo-burst
pa...