Intruder detection apparatus for functioning free of disturbance while in close proximity to high-power pulse-moldulated radars

摘要

In the receiver of an outdoor intruder detection apparatus, which receiver is spaced from and receives signals from a microwave transmitter and provides an alarm output upon the occurrence of change in the received signal, eliminator means is provided for eliminating pulses which may be superimposed on the signals from nearby radar. Such eliminator means comprises a wide band amplifier which serves, by way of a monostable to actuate a switch which gates out, in synchronism with the superimposed pulses, the detected signals from an aerial and diode as supplied by way of amplifiers and a delay line to further signal- processing circuitry.