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:
Aug. 04, 1992
Filed:
May. 22, 1991
Applicant:
Inventors:
Assignee:
Deutsche Thomson-Brandt GmbH, Hanover, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4425 ; 369 4429 ; 369 4432 ; 369 4434 ; 369 54 ;
Abstract
A tracking circuit for guiding a beam of light along data tracks of a recorded medium as compact disks and video disks, in which the recorded medium reflects a light beam onto a photodetector. The photodetector has an output voltage that is applied to a servo through a variable-gain amplifier. A compensation voltage is superimposed over the output voltage from the photodetector during the open state of the circuit to compensate off said voltages. This compensation voltage is varied until the sum of the output voltage from the photodetector and the compensation voltage attains a predetermined value. Thereafter the circuit is closed.