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:
Feb. 22, 1994
Filed:
Oct. 13, 1992
Anthonius L Dekker, Zurich, CH;
Antonius H Akkermans, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A device for scanning a record carrier having essentially parallel tracks produces detection signals (AS, . . . , FS) which depend on the location of the scanning point relative to the tracks and from which are derived a tracking error signal (RE) and a track position signal (TP). A comparator (7) detects whether the track position signal intersects a first threshold (D1), and a comparator (6) detects whether the tracking error signal is located within an amplitude window established by a second positive threshold (D2) and a third negative threshold (D3). A signal processor (8) derives a track loss signal from the results of the detections performed by the comparators (6, 7), which track loss signal signifies that the scanning point no longer follows the track. The track loss signal is not produced unless an intersection of the first threshold by the track position signal is detected and, furthermore, the tracking error signal is outside of the amplitude window during a specific time window around such intersection. In this way, momentary disturbances of the detection signals caused by narrow interruptions of the tracks, due to record carrier errors, do not result in erroneous track loss signals.