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:
Jun. 03, 2003
Filed:
Jan. 12, 2001
YangQuan Chen, Singapore, SG;
MingZhong Ding, Singapore, SG;
LinCheng Xiu, Singapore, SG;
KianKeong Ooi, Singapore, SG;
LeeLing Tan, Singapore, SG;
Seagate Technology LLC, Scotts Valley, CA (US);
Abstract
A repetitive learning compensator for a servo system of a disc drive includes a memory buffer having a length N/m where N is the number of servo sectors in a track, m is a parsing factor greater than 1 and N/m is an integer. A down sampler supplies servo signals containing error signals to the repetitive learning compensator at a frequency of f /m, where f is a sampling frequency based on N and a fundamental frequency f of the spindle motor. An up sampler supplies filtered signals from the repetitive learning compensator to the actuator assembly at the sampling frequency f . One aspect of the disclosure includes tuning the repetitive learning compensator with a phase advance represented by N and a cutoff frequency f , where N and f are selected as a pair to provide the greatest transfer function amplitude at the harmonic frequencies for the repetitive learning compensator.