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:
Oct. 20, 2009
Filed:
Dec. 04, 2007
Applicant:
Akihiro Yamazaki, Kawasaki, JP;
Inventor:
Akihiro Yamazaki, Kawasaki, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 21/02 (2006.01);
U.S. Cl.
CPC ...
Abstract
A harmonic wave obtaining unit performs a fast Fourier transform (FFT) operation on repeatable run out (RRO) correction data in the time domain and transforms the RRO correction data into a higher harmonic signal data in the frequency domain. A selective-output unit outputs wavelength and amplitude of a first-order harmonic wave and of a third-order harmonic wave of the higher harmonic signal data to a hard disk controller via a formatting unit. A hard disk controller calculates a head-gap between a magnetic head and a magnetic disk in a storage device at the time of reading user data as well as servo data.