Proximity surveillance object state installation having transmitter/receiving transmitting transponder object placed and having parameter detector/processing circuit and coder/decoder processing signals/oscillating circuit passing

摘要

The surveillance installation has an electromagnetic transmitter receiver (11) transmitting from an antenna (12) and a processing circuit (13). A transponder (2) placed on the protected object has an oscillating circuit (21,22) receiving the transmitted power. The transmitter has an environmental parameter detector (25) with a processing circuit (24) and a coder/decoder (23) receiving processed signals to inject in the oscillating circuit.