US 5,491,839 AGranted

System for short range transmission of a plurality of signals simultaneously over the air using high frequency carriers

AssigneeL. S. Research, Inc.

InventorLarry Schotz

Life of this patent

Estimating the term…

Loading patent…

Abstract

A transmitter/receiver system for the simultaneous transmission and reception of plural audio signals over the air for a short range using carrier signals of frequencies over 900 MHz. A combined signal having a plurality of carrier signals, each modulated by a different audio signal, is transmitted. The receiver, separated from the transmitter by a distance of 10 to 300 feet, receives the combined signal and the listener then selects one of the frequency modulated carrier signals in the combined signal at the receiver with a selector switch. One of a set of combined signals is selected at the transmitter, allowing for a choice of different frequencies for transmission, to avoid interference with other systems in the vicinity. Moreover, where predetermined, e.g., fault, conditions occur in the transmitter and/or receiver, muting circuits within the receiver are activated for the duration of the predetermined, e.g., fault, condition to silence the audio output signal to the listener and thereby prevent the thumping and hissing that a listener usually experiences during power transients and unlocked signal conditions.

Claims38

Dependent claims

A system for transmitting and receiving plural electrical signals, each of said plural electrical signals representing respective electrical input signals provided from at least respective first and second high fidelity audio sources to said system, said system comprising:

(a) transmitter means comprising:
(1) input means for receiving said plural electrical signals;
(2) selectable sinusoidal carrier signal producing means for selectably providing at least a first group of sinusoidal carrier signals from plural groups of plural sinusoidal carrier signals, each of said groups comprising at least a first carrier signal and a second carrier signal, said first carrier signal of each of said groups being associated with said first audio source, said second carrier signal of each of said groups being associated with said second audio source, each of said sinusoidal carrier signals of each of said group being preselected and different from the others of said groups and at a frequency of at least 900 MHz, said selectable sinusoidal carrier signal producing means comprising a set of frequency synthesizer means, one respective frequency synthesizer means for each of said electrical input signals, said frequency synthesizer means generating said different sinusoidal carrier signals of said frequency of at least 900 MHz;
(3) modulating means for modulating each of said carrier signals of said first group with a respective one of said plural electrical signals to produce a plurality of modulated carrier signals;
(4) combining means for combining said modulated carrier signals into a combined signal;
(5) antenna means for radiating said combined signal over the air;
and
(b) receiver means for receiving said combined signal.

5 more elements

Dependencies are inferred from the claim text.