Patent ID: 6945935

Claim:
Apparatus for physiological monitoring of a remote subject including: a base station having a transmission means for transmitting a reference signal; and at least one physiological monitoring probe connectable to said subject, said physiological monitoring probe or probes having: receiver means for receiving said reference signal; monitoring means for monitoring said subject and generating a condition signal containing information related to a condition or conditions of said subject; intermediate signal means for generating an intermediate signal derived by combining said condition signal with a fixed or varying frequency sub-carrier signal before modulating said reference signal; modulation means for modulating said reference signal with said intermediate signal to produce a modulated reference signal containing said information contained in said condition signal; and passive retransmission means for passively retransmitting said modulated reference signal to said base station; wherein said base station has means for receiving said modulated reference signal, and means for demodulating said modulated reference signal to obtain said information related to one or more conditions of said subject so that at least one condition of said subject is available to be monitored at said base station, and said base station includes means for varying the frequency or phase of the reference signal so that said reference signal is a spread spectrum reference signal.