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:
Mar. 11, 2014
Filed:
Mar. 27, 2012
Jiangang Liang, San Jose, CA (US);
Siri S. Weerasooriya, Campbell, CA (US);
Yilin Cai, Fremont, CA (US);
Jiangang Liang, San Jose, CA (US);
Siri S. Weerasooriya, Campbell, CA (US);
Yilin Cai, Fremont, CA (US);
Western Digital Technologies, Inc., Irvine, CA (US);
Abstract
A disk drive is disclosed comprising head actuated over a disk comprising a reference pattern. The head is positioned at a first radial location, a first phase error is measured in response to the reference pattern at the first radial location, and a first repeatable runout (RRO) of the first phase error is measured. The head is positioned at a second radial location, a second phase error is measured in response to the reference pattern at the second radial location, and a second repeatable runout (RRO) of the second phase error is measured. The first and second RROs are processed to estimate an offset rrepresenting a difference between an axial rotation of the disk and an axial rotation of the reference pattern.