Burst frequency shift keying data communication system
US3944742A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 1, 1974 |
| Grant date | Mar 16, 1976 |
| Priority date | — |
| Expiry date | Apr 1, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/173
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A communications system for transmission of low density digital data from a plurality of transmitters to a common receiver. It is a burst-mode frequency shift keying (FSK) communication system useable with a master antenna television (MATV) system that minimizes mutual interference between outputs of a large number of transmitters individually located with TV sets. The transmitters are combined with converters for transmission of programs through the system to individual TV sets as controlled by the users, and with information such as TV channel in use, room number identification, and specialized information such as completion of maid service, fire, and burglary alarms transmitted back through the system. In one system the transmitters use a carrier frequency of 12MH.sub.z, a frequency at the lower end of the passband of a coax system with FSK modulation at an equivalent switching rate of 20KH.sub.z and modulation index of 5 accepting a RF channel loading of up to 700 simultaneous users.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.