Memory select system for an STV decoder
US4460922A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 18, 1981 |
| Grant date | Jul 17, 1984 |
| Priority date | — |
| Expiry date | Nov 18, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/1675
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.