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:
Sep. 28, 2004
Filed:
Oct. 26, 2000
Mitsuo Kamimura, Kawasaki, JP;
Yoshinari Higashino, Kawasaki, JP;
Kiyoshi Sakuma, Kawasaki, JP;
Yukio Abe, Higashine, JP;
Kunihiro Shimada, Kawasaki, JP;
Atsushi Suzuki, Higashine, JP;
Takeshi Hara, Kawasaki, JP;
Kentaroh Katoh, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
The controller circuit is designed to generate the positioning control signal based on the positional deviation of the head from a target recording track on a recording medium. A feedback control is effected to position the head right on a trajectory corresponding to the target recording track based on the generated positioning control signal. The positioning control signal is subjected to filtering at a notch filter. The cutoff frequency of the notch filter is set depending on the temperature detected at a thermal sensor. Even when the resonant frequency shifts in response to variation in temperature, the cutoff frequency of the notch filter follows the shift of the resonant frequency. A narrower bandwidth of the cutoff frequency still achieves reduction in the amplitude of the frequency component corresponding to the resonant frequency. The resonance or continuous vibration can reliably be prevented in the head. A rapid response can be accomplished in positioning the head right on a trajectory corresponding to the target recording track because of a narrower bandwidth of the cutoff frequency.