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. 06, 1998
Filed:
Jul. 07, 1997
Tomoaki Nakamura, Ohta, JP;
Terumitsu Okamoto, Ohta, JP;
NEC Corporation, , JP;
Abstract
After application of power or insertion of a medium, a frequency bandpass digital filter extracts the first-order component, which has one period per revolution of the medium, and the second-order component, which has two periods per revolution of the medium, from the carriage operation amount for one revolution of the medium, this being written into a carriage operation amount compensation table. Then, a position error averaging section calculates the average value of a tracking error signal, and a compensation table updating judgment section monitors this position error average value. If the position error average exceeds a prescribed threshold value for a number of consecutive sectors, the second-order component only is updated in the carriage operation amount compensation table. An actuator driving section controls the carriage in accordance with a corrected operation amount obtained by adding the operation amount obtained at the carriage operation amount calculation section and the compensation amount of the carriage compensation table. The results in stable position control of the head, without the influence of ambient temperature changes on the off-track amount.