| 摘要 |
Method and device for intrusion detection with UHF barrier. A transmitter 1 produces an unmodulated directive UHF beam towards a remote monitoring receiver 2, tasked with detecting and signalling any significant variation in the UHF signal received. The signal received by a sensor 8 in the monitor receiver is modulated, on or off, in this receiver by means of a switching member of the analog AND gate type 10 which is controlled at the rate of a local oscillator 11 of the receiver. The chopped signal obtained is conventionally applied to a signalling control arrangement 12 via an amplifier arrangement 14. <IMAGE>
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