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:
Mar. 17, 1987
Filed:
Jun. 20, 1984
Gerald O Crowther, Sutton, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
In a television receiver for a transmission system in which the video signal is scrambled to allow only for its authorized reception, a video signal processor (8) is provided in which the scrambled video signal is de-scrambled. A low rate control data signal present at an output (11) of a sound/data signal processor (10) is employed to periodically set (say once every one or two seconds) a master pseudo random pulse generator (12B) producing an output of pseudo random configuration at frame rate which is used to periodically set a video slave pseudo random pulse generator (15) to produce an output of pseudo random configuration at line frequency. This is applied to an input S of the processor (9) and forms the scrambling key for the line-by-line de-scrambling of the video signal. The arrangement has the advantage that the high rate scrambling key is not produced by the first generator (12B) where this generator forms part of a sub-system (13) and so prevents high rate data being present across the sub-system interface.