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:
Jun. 10, 2008
Filed:
Nov. 05, 2004
Takashige Hiratsuka, Saijo, JP;
Takashige Hiratsuka, Saijo, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The address signal position detection apparatus comprises a photodetector, a first and second adders which generate, from the output signals from the photodetector, two signal sequences whose phases change from each other according to a tracking error of a light spot, a phase difference detection circuit for detecting the phase difference from the two signal sequences, and a phase difference signal processing unit which generates an address signal position using the phase difference signal detected by the phase difference detection circuit, and detects an address signal position by providing threshold values with respect to the detected phase difference, thereby enabling a stable detection of the address signal position even when a DC symmetry in a difference signal of a reproduced signal is imperfect in an optical disk using the land/groove recoding method.