Patent Number:
8,792,202
Title:
Disk drive adjusting rotation speed of disk to compensate for blind area when measuring frequency response of servo control system
Abstract:
A disk drive is disclosed comprising a head and a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors. The disk drive further comprises control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. The disk is rotated at a first speed and the servo sectors are read at a first servo sample frequency to generate first servo samples. The disk is rotated at a second speed different from the first speed and the servo sectors are read at a second servo sample frequency to generate second servo samples. The second servo samples are processed to measure a frequency response of the servo control system proximate the first servo sample frequency.
Inventors:
Wan; Jie (Singapore, SG), Xu; Xiaotian (Singapore, SG), Cao; Shuyu (Singapore, SG), Tan; Jern Khang (Muar, MY), Guo; Guoxiao (Irvine, CA), Xi; Wei (Mission Viejo, CA)
Assignee:
Western Digital Technologies, Inc.
International Classification:
G11B 5/596 (20060101); G11B 20/20 (20060101)
Expiration Date:
7/29/12018