Seagate Technology Incorporated

LinCheng Xiu

KianKeong Ooi

MingZhong Ding

YangQuan Chen

LeeLing Tan

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.

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Singapore, Singapore

LinCheng Xiu