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:
Sep. 12, 1995
Filed:
Aug. 06, 1993
Dieter Baas, Kehl-Auenheim, DE;
Deutsche Thomson-Brandt GmbH, Villingen-Schwenningen, DE;
Abstract
A disc playback apparatus includes a system for scanning a disc and storing in memory, an address associated with every point on the disc where the scanning device mistracks. A modified regulating signal is calculated for guiding the scanning device back onto the desired data track, from the value of the regulating signal generated by the tracking regulation circuit prior to track loss. The modified regulating signal is also stored in the memory, and during every subsequent reading of the disc, upon encountering track areas associated with stored addresses, the tracking regulation circuit is provided a corresponding modified regulating signal in order to maintain the scanning device near the desired data track. In further scans of the disc successive modified track regulating signals are iteratively generated and tested for tracking response until a substantially optimum modified signal is generated. The optimum modified regulating signal is then stored in memory associated with the address of respective disc defects. The optimum regulating signal is determinable by monitoring the polarity of the tracking signal after application of the modified signal. The first occurrence of a polarity change is an indication that the respective iteration of generating a modified signal has produced the desired signal.