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:
Apr. 23, 2002
Filed:
Dec. 17, 1999
Yasushi Toda, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A defined level comparator compares a track error signal with each of a predetermined upper limit level and a predetermined lower limit level so as to generate two comparison signals. A logic unit ANDs two comparison signals so as to obtain a track pull-in enabling signal. A header component removal arithmetic unit removes a header component from the track pull-in enabling signal in accordance with a header area signal. A track polarity inverter outputs a land/groove detection signal in which a polarity of a signal level is inverted every timing at which a signal level of the track pull-in enabling signal is in a track pull-in enabling state. A track polarity correcting and determining unit compares a polarity signal held by a sampling holder with the land/groove detection signal in the header area. The track polarity correcting and determining unit corrects the signal level of the land/groove detection signal to the signal level held by the sampling holder when both signal levels are different from each other.