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:
Jan. 31, 2006
Filed:
Sep. 19, 2000
Akira Mashimo, Tokorozawa, JP;
Keishi Ueno, Hanno, JP;
Akira Mashimo, Tokorozawa, JP;
Keishi Ueno, Hanno, JP;
Teac Corporation, , JP;
Abstract
A wobble signal detection circuit is provided for an optical disk apparatus which detects a wobble signal by focusing a light beam into a spot on a pregroove on an optical disk during recording of data onto and reproduction of data from the optical disk, and includes a photodetector which detects first and second lights from first and second portions of the spot, respectively, and outputs first and second detection signals corresponding to respective power levels of the first and second detection lights. The wobble signal detection circuit includes: a sample-and-hold circuit sampling and holding the first and second detection signals output from said photodetector during the recording of the data onto the optical disk; lowpass filter means for reducing noise components of the respective first and second detection signals; and subtraction means for calculating a difference between the first and second detection signals respectively output from said lowpass filter means so as to obtain the wobble signal.