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. 26, 1991
Filed:
Jun. 21, 1988
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A recording medium drive apparatus has a first detector for detecting tracking information and a second detector for detecting focusing information when magnetization information and pit information recorded on an optical disc are reproduced and detected. This apparatus also comprises a preamplifier having the function of selecting by a control signal either a mode for adding and amplifying output signals of the first and second detectors by utilizing a predetermined gain or a mode for subtracting and amplifying those output signals by utilizing another predetermined gain, of unconditionally selecting the polarities of the added and subtracted amplification signals by means of the control signal, and of selectively outputting signals V.sub.i (i=1, 2, 3, 4).