Burst frequency shift keying data communication system
First Claim
1. In a burst-mode frequency shift keying communications system utilizing one way transmission of digital data from a plurality of RF transmitter stations to common receiving means;
- a plurality of RF transmitter stations each capable of generating short burst transmissions in the form of a plurality of bit elements with signal level transitions between different logic levels with the bit element signal level transition leading edges being an imbedded clock sensed by receiver means, and with the short burst transmissions being of short time duration relative to repetition time periods between short burst transmissions from an RF transmitter station;
common receiving means for receiving burst-mode frequency shift keying modulated RF signals transmitted through an RF signal transmission media from said RF transmitter stations to said common receiving means;
gating means for short burst transmissions for each of said RF transmitter stations;
for each transmitter station repetition period gate activating means for activating said gating means associated with said corresponding RF transmitter stations for short burst transmissions;
digital signal demodulating means in said common receiving means; and
signal imbedded clock detecting means in said common receiving means with said digital signal demodulating means activated by said signal imbedded clock.
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Accused Products
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 12MHz, a frequency at the lower end of the passband of a coax system with FSK modulation at an equivalent switching rate of 20KHz and modulation index of 5 accepting a RF channel loading of up to 700 simultaneous users.
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Citations
15 Claims
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1. In a burst-mode frequency shift keying communications system utilizing one way transmission of digital data from a plurality of RF transmitter stations to common receiving means;
- a plurality of RF transmitter stations each capable of generating short burst transmissions in the form of a plurality of bit elements with signal level transitions between different logic levels with the bit element signal level transition leading edges being an imbedded clock sensed by receiver means, and with the short burst transmissions being of short time duration relative to repetition time periods between short burst transmissions from an RF transmitter station;
common receiving means for receiving burst-mode frequency shift keying modulated RF signals transmitted through an RF signal transmission media from said RF transmitter stations to said common receiving means;
gating means for short burst transmissions for each of said RF transmitter stations;
for each transmitter station repetition period gate activating means for activating said gating means associated with said corresponding RF transmitter stations for short burst transmissions;
digital signal demodulating means in said common receiving means; and
signal imbedded clock detecting means in said common receiving means with said digital signal demodulating means activated by said signal imbedded clock. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- a plurality of RF transmitter stations each capable of generating short burst transmissions in the form of a plurality of bit elements with signal level transitions between different logic levels with the bit element signal level transition leading edges being an imbedded clock sensed by receiver means, and with the short burst transmissions being of short time duration relative to repetition time periods between short burst transmissions from an RF transmitter station;
Specification