The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 31, 2004
Filed:
Apr. 27, 2001
ShuangQuan Min, Singapore, SG;
KianKeon Ooi, Singapore, SG;
YangQuan Chen, Singapore, SG;
Ricky Wei Watt Yeo, Singapore, SG;
WeiSung Lee, Singapore, SG;
BengWee Quak, Singapore, SG;
Seagate Technology LLC, Scotts Valley, CA (US);
Abstract
Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo burst closures, D(n ), is read over a plurality of tracks, and a maximum servo burst closure D(n ) is identified from the plurality of read servo bursts. A magnitude of the cage frequency at a servo sector n is calculated based on a difference between the read magnitudes of the servo burst closures at servo sectors n and n , and a phase of the cage frequency is calculated based on the magnitude of the written-in cage frequency at servo sector n . The profile, in the form of cage frequency, maximum servo burst closure magnitude, and initial phase, is stored in a memory or table for each of a plurality of radial zones of tracks. The profile is combined with a position error signal and applied to the controller in a feed forward scheme to adjust the position of the head based on the written-in runout.