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:
Apr. 07, 1998
Filed:
Feb. 15, 1995
U.S. Philips Corporation, New York, NY (US);
Abstract
An information system including a record carrier and a playback apparatus. Information has been recorded on the record carrier in the form of variations of a first physical parameter. The playback apparatus scans the record carrier by means of a transducer which is responsive to the variations of the first physical parameter. An information recovering circuit recovers the information from a detection signal received from the transducer. The record carrier also exhibits second variations of a second physical parameter, which differs from the first physical parameter, but which second variations are of a type that are detectable by the transducer. A detection circuit detects the presence of the second variations or a predetermined property thereof (e.g., that they exhibit a predetermined variation pattern) on the basis of the detection signal received from the transducer. A circuit responsive to the detection circuit enables the information recovering circuit, when the presence of the second variations or a predetermined property of the second variations is detected, causing it to recover the information.