UHF_MOTION_DETECTOR

Published:2009/7/9 22:16:00 Author:May | From:SeekIC

The UHF motion detector operates on the Doppler radar principle. Q1 is an oscillator that creates a adiated signal. An object in the radiated field reflects some of this energy back to the detector. If the ect is moving, the reflected signal will have a different frequency because of Doppler shift.Q1 is an oscillator coupled to a small (8-cm) antenna. This antenna also receives the reflected signal. D1 acts as a mixer and produces a beat note of frequency that is equal to the difference in reflected nd radiated signal. Q2 amplifies this signal and couples it to comparator/detector IC1A and IC1B. The utput can continue on to an alarm, relay, lamp,etc.



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