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:
Jul. 17, 1984
Filed:
Nov. 18, 1981
James W Ensinger, Roselle, IL (US);
Melvin C Hendrickson, Elmhurst, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
A subscription television system includes means broadcasting a scrambled television signal encoded with p-bit program and subscriber authorization codes and m-bit memory write and read codes. Each subscriber is provided with a decoder having (2.sup.m) p-bit memory locations, the decoder being operable for storing a broadcast p-bit subscriber authorization code in a memory location defined by the broadcast m-bit memory write code for updating the decode authorization status of the subscriber and being operable for comparing a broadcast program code with a subscriber authorization code stored in a memory location defined by the broadcast m-bit memory read code for developing a decode authorization signal to effect unscrambling of the broadcast television signal.