Digital information signal transmitting/receiving method and system
US5719943A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 1995 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Mar 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/937
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A digital information signal transmitting/receiving method and system having a transmitter for transmitting an encrypted digital information signal and a plurality of receivers for receiving the encrypted digital information signal from the transmitter. The transmitter simultaneously distributes a plurality of identification codes associated with the receivers at a time ahead of the digital information signal. The receivers detect whether a particular identification code assigned to the receiver was included within a received plurality of identification codes. When the particular identification code has been detected as having been received the received encrypted digital information signal is decrypted into the original digital information. In order to request that a particular identification code be included so as to allow access to a program, either one of the receivers or the recorders each generate an information request signal. The transmitter is responsive to the information request signals to add to the digital information signal at a time ahead of the digital information signal, identification signals for identifying the receivers or the recorders which generated the inform…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.