Validation apparatus in a pay television system
US4250524A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 22, 1979 |
| Grant date | Feb 10, 1981 |
| Priority date | — |
| Expiry date | Feb 22, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/163
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A validation apparatus in a pay television system, including a code detector means for successively detecting a sequence of code signals, from an encoded composite TV signal, a key code circuit means having a key code so as to validate the sequence of code signals detected in said code detector means for generating a first, a second and a third control signals in response to said sequence of code signals, a polarity flip-flop means being set by the first control signal, thereby assuming a first state and being reset by the second control signal, thereby assuming a second state and being toggled by the third control signal, thereby changing from the first state to the second state or changing from the second state to the first state, a counter means for generating an output signal when the number of state changes in said flip-flop means reaches a predetermined value, a feature detector means for generating an output signal when the detector means receives said third control signal in a predetermined number of times which is peculiar to said sequence of code signals, and a gating means for generating an output signal so as to generate a valid signal representing that said encoded com…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.