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:
Jun. 06, 2000
Filed:
Jan. 27, 1998
Kevin T Chang, Neshanic Station, NJ (US);
Alfred W Stufflet, Norristown, PA (US);
General Instrument Corporation, Horsham, PA (US);
Abstract
A signal such as an analog scrambled television signal in a cable television network has first scrambling mode data which is compatible with a first decoder population, but not a second decoder population. The scrambled television signal is processed to determine the scrambling mode without recovering the first scrambling mode data. Second scrambling mode data which is compatible with the second decoder population is then provided in the scrambled television signal, for example, in the vertical blanking interval or on an audio subcarrier. During processing to determine the scrambling mode, the television signal is delayed, e.g., by digitizing it and temporarily storing it in memory. The delay compensates for the time required to determine the scrambling mode. The television signal is recovered in the analog domain prior to inserting the second scrambling mode data. The system is compatible with various scrambling modes, including sync suppression and inversion of the active video as well as with dynamic scrambling mode changes.