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. 02, 2007
Filed:
Feb. 23, 2004
Shintaro Takehara, Yokohama, JP;
Shintaro Takehara, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A tracking error detection device for an optical disk apparatus comprises a detecting unit which includes at least two detectors and detects a reflected light from a series of pits formed on an optical disk, a phase comparing unit which detects a phase difference of outputs of the at least two detectors, and a low-pass filter which smoothes an output of the phase comparing unit, a cut-off frequency of the low-pass filter being higher than a frequency at which a spectrum of a modulation code recorded in the optical disk becomes −10 dB and lower than a frequency at which the spectrum of the modulation code recorded in the optical disk becomes −5 dB.