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. 16, 1991
Filed:
Sep. 28, 1988
Heinz-Jorg Schroder, Villingen-Schwenningen, DE;
Deutsche Thomson-Brandt GmbH, Villingen-Schwenningen, DE;
Abstract
A tracking circuit for an optical scanner to return a light beam to a data storage track of a disk that was scanned by the light beam, after the light beam was deflected away as a result of an outside random shock or vibration. A difference amplifier generates a tracking error by taking the difference between two photovoltages. A directional logic circuit in the form of a D flip-flop determines which direction the light beam was deflected away from the data storage track that was scanned by the light beam. The light beam may skip storage tracks when it is deflected away from the track that was being scanned. The number of storage tracks that were skipped by the light beam, in this manner, are counted by an up-and-down counter, and this counter emits a control signal which is dependent on the state of the counter for deflecting the light beam back to the data storage track that was scanned. The counter output is applied to a control amplifier through a pulse shaper. The output of the difference amplifier in the form of the tracking error is applied to the control amplifier through a controllable switch that has a control input from the counter.