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:
Jul. 15, 2008
Filed:
Mar. 28, 2005
Hiroshi Mitsuda, Osaka, JP;
Hiroshi Mitsuda, Osaka, JP;
Funai Electric Co., Ltd., , JP;
Abstract
The present invention provides an optical disk recording and reproducing apparatus having a circuit configuration whereby it is possible to prevent tracking drive signals from being offset even when the temperature of a tracking actuator drive circuit is increased. The output resistance of a low-pass filteris composed of two serially connected resistors Rand R, the resistance of the former one Rof the serially connected resistors Rand Rbeing arranged to be lower than that of the latter one Rand a connecting point S between the former and latter resistors Rand Rbeing connected to the input side of an A/D port, whereby the potential difference between a tracking output portand the A/D portis reduced as much as possible, and thereby the reference voltage value stored in a reference voltage value storing meansapproaches an exact value as close as possible, which increases the accuracy of comparison results of a comparing meanssubstantially, and therefore a D/A conversion and offset cancel circuitcan output a tracking drive signal without offset.