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:
Feb. 02, 1999
Filed:
Jun. 12, 1996
Toshiro Hattori, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A state variable estimator is operative, in a change-over of a magnetic head, to determine a predicted value of a state variable of a frequency-shaped filter in a follow-up to a track after the change-over based on a current head position of thereof before the change-over, by using a set of calculated coefficients representative of an amplitude and a phase difference relative to the current head position of a sine wave to be calculated by a discrete Fourrier series, as the sine wave represents the state variable of the frequency-shaped filter when the track is followed up, so that a state variable re-setting of control system is achieved to minimize a square error integration of the predicted value and a state variable of a phase compensating filter, as the change-over is a step response of a closed loop control system.