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:
Dec. 29, 1987
Filed:
Oct. 29, 1985
John R Thompson, La Quinta, CA (US);
Curtis J Hunting, Altadena, CA (US);
Ronald K Masson, Topanga, CA (US);
Craig E Trivelpiece, Irvine, CA (US);
Payview Limited, , HK;
Abstract
A multimode scrambling system for video signal transmission systems is described. The system provides for baseband video scrambling controlled by a central originating computer facility. The scrambling of each field of a video changes on a per field basis. The video signal is scrambled in several modes including vertical interval scrambling, alternate line inversion, bogus sync pulse generation, video compression and video offset techniques. A scrambling sequence is sent by a unique algorithm, sent during the vertical interval to each system decoder. The algorithm is reordered for each of a plurality of fields of the video signal and the reordering position is identified by a unique synchronization pulse transmitted during the vertical interval of the video signal. Additional security measures are provided to inhibit a subscriber from avoiding a transmitted disable command, or an attempt to invade the subscriber decoder mechanical packaging security.