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Browse Prior Art Database

Non-Contact Asperity Detection for Glide Height Testing

IP.com Disclosure Number: IPCOM000113097D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Calcagno, PA: AUTHOR [+3]

Abstract

The following describes a method used to achieve a constant output from a piezo electric crystal mounted on a glide height test head; over an asperity at a given height; at any radius on the disk; while the disk achieves a constant revolution per minute; and the head flying in a non-contact detection mode above the asperity peaks.

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

Non-Contact Asperity Detection for Glide Height Testing

      The following describes a method used to achieve a constant
output from a piezo electric crystal mounted on a glide height test
head; over an asperity at a given height; at any radius on the disk;
while the disk achieves a constant revolution per minute; and the
head flying in a non-contact detection mode above the asperity peaks.

      The process described utilizes one RPM for the spinning media
at a rate in which the air bearing resonance of the asperity causes a
modulated signal from the glide head.  The glide head must be skewed
at the inner and outer diameters in order to create a consistent
output from a nominal asperity at both linear velocities.  This inner
and outer skew is used to create a linear path for the glide head to
traverse across the media.  One obtains a constant detection level
from the inner to the outer diameter by producing one skew angle and
offset from the radial centerline of the media using the two angles
given.  This then provides a linear path from the inner to outer
diameters.