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:
Mar. 09, 2004
Filed:
May. 29, 2002
Eiji Ueda, Yawata, JP;
Yasumori Hino, Ikoma, JP;
Takashi Inoue, Osaka, JP;
Hideki Ohyama, Tamana-gun, JP;
Kiyokazu Hashimoto, Matsubara, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A tracking error signal detector includes: a photodetector ( ) for detecting reflected light from an optical recording medium having a servo area provided with a first wobble mark and a second wobble mark; an amplifier ( ) for producing a summation signal of the reflected light; a sampling portion ( ) for sampling the summation signal; a first arithmetic portion ( ) for calculating an extremum of the summation signal in the vicinity of reproduction timing for each of the first and second wobble marks from the sampling values so as to produce first and second extremums; and a second arithmetic portion ( ) for producing a tracking error signal that corresponds to a difference between the first and second extremum. The tracking error signal detector can produce a high-accuracy tracking error signal even if sampling is performed with an asynchronous clock relative to the summation signal.