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. 15, 1994
Filed:
Feb. 10, 1993
Applicant:
Inventors:
Richard Westerfer, Blue Bell, PA (US);
Henry S Landgraf, Haddon Township, Camden County, NJ (US);
Assignee:
General Instrument Corporation, Hatboro, PA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04N / ;
U.S. Cl.
CPC ...
380 15 ; 380 20 ;
Abstract
In order to defeat pirate descramblers that detect the occurrence of a vertical blanking interval from a gap in timing data provided on the sound carrier of a scrambled television signal, diversionary pulse information is inserted into the sound carrier during the vertical blanking interval. A pirate descrambler that looks for a gap in data transmitted on the sound carrier will then detect a 'false' second gap, and incorrectly phase lock its horizontal oscillator to random video instead of to horizontal timing information that is recoverable during the vertical blanking interval.