Radio frequency communication systems
First Claim
1. A radio frequency communication system comprising a transmitter, a receiver, a radiating transmission line having a distal end connected to the receiver and having a proximal end connected to the transmitter, a unidirectional repeater in the radiating transmission line for repeating signals in a single direction only, and a mobile station adjacent the radiating transmission line, the mobile station including a mobile receiver to receive signals radiated from the transmission line and a mobile transmitter for transmitting signals to the transmission line, and a direct link line connecting the receiver with the transmitter whereby the link line provides a return path for demodulated signals in the audio frequency range.
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Accused Products
Abstract
A radio communication system suitable for use in tunnels and mines uses a leaky radiating transmission line connected between a transmitter and a receiver to transmit radio frequency signals to a local receiver. Unidirectional repeaters are located in the transmission line and a return path is provided by a normal wire carrying demodulated signals from the receiver to the transmitter.
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Citations
5 Claims
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1. A radio frequency communication system comprising a transmitter, a receiver, a radiating transmission line having a distal end connected to the receiver and having a proximal end connected to the transmitter, a unidirectional repeater in the radiating transmission line for repeating signals in a single direction only, and a mobile station adjacent the radiating transmission line, the mobile station including a mobile receiver to receive signals radiated from the transmission line and a mobile transmitter for transmitting signals to the transmission line, and a direct link line connecting the receiver with the transmitter whereby the link line provides a return path for demodulated signals in the audio frequency range.
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2. A radio frequency communication system According to claim 1, the mobile transmitter operating at a different frequency to a frequency of the said transmitter.
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3. A radio frequency communication system as claimed in claim 1, and including a branch line from the said transmission line, a separate local receiver terminating the branch line and a separate link line connecting the said local receiver with the transmitter.
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4. A radio frequency communication system as claimed in claim 1 and including a plurality of branch transmission lines extending from the said transmission line, a respective local receiver for terminating each of said branch transmission lines and a common link line connecting all of the local receivers with the receiver of the said transmission line.
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5. A radio frequency communication system as claimed in claim 1, and including a plurality of branch transmission lines extending from the said transmission line, a respective local receiver for terminating each of said branch transmission lines and a common link line connecting all of the local receivers with the said transmitter of the system.
Specification