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:
Mar. 11, 1997
Filed:
Nov. 21, 1994
Masashi Arai, Gunma, JP;
Akira Tsukihashi, Gunma, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
An error signal generating circuit for adjusting a position of a sub-beam on an optical disc to a correct one. A timing circuit generates a test signal so that a driver drives a tracking coil. As a result, a difference signal is generated in a difference signal generating circuit and is then compared to a reference value in a comparing circuit. A controlling signal is generated in a controlling circuit in reply to a comparing error so as to be held in a holding circuit. The thus held controlling signal is converted into an analog signal in a D/A converter and is then applied to a VCA to vary the amplifying rate, such that the difference signal becomes zero when a correct tracking operation is being carried out.