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Offtrack Read with Auto Gain Control Hold for Thermal Disturbance Recovery

IP.com Disclosure Number: IPCOM000117428D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Asano, H: AUTHOR [+4]

Abstract

This article describes Auto Gain Control (AGC) circuit gain-hold (AGC HOLD) mode selection during offtrack read operation for error recovery from thermal disturbance on HDD system with Magneto Resistive (MR) head.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Offtrack Read with Auto Gain Control Hold for Thermal Disturbance
Recovery

      This article describes Auto Gain Control (AGC) circuit
gain-hold (AGC HOLD) mode selection during offtrack read operation
for error recovery from thermal disturbance on HDD system with
Magneto Resistive (MR) head.

      When read operation is unsuccessful at nominal read position on
target track, offtrack read operation starts to avoid thermal
disturbance spot by disk asperity, within track.

      During offtrack read operation, gain hold mode is selected on
the around error region to protect read-back signal quality from
sudden AGC response against extra peak generation by disk thermal
asperity that can distort signal further more for detection channel
circuit in the following of AGC.

      This AGC HOLD enhances offtrack read effect on error recovery
from thermal disturbance.  The Figure shows an example of offtrack
read sequence.