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:
Feb. 14, 2006
Filed:
Jul. 17, 2002
Kouichi Urita, Saijo, JP;
Youichi Ogura, Saijo, JP;
Shinichiro Sato, Saijo, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disc playback apparatus that performs appropriate waveform equalization according to a difference in characteristics of reproduced signals between land parts and groove parts in an optical disc to which high-density recording is performed using a land/groove recording method. The optical disc playback apparatus includes a reproduction device, an A/D conversion circuit for sampling a reproduced signal to be converted into a multi-bit digital signal, a filter for subjecting the multi-bit digital signal to digital equalization, a filter coefficient learning device for adaptively controlling filter coefficients for the filter corresponding to the land part and the groove part to minimize an equalization error, and a switch signal generation device for generating a signal for switching between land and groove, thereby changing the filter coefficient adaptively to the land or the groove.