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专利名称：Occupancy sensor
发明人：Maclyn C. Cameron, Jr.,Charles C. Hu,Jerome
M. Mix
申请号：US06/872308申请日：19860609公开号：US04661720A公开日：19870428
摘要：An improved apparatus for switching off power to an electric load in the
absence of the detection of movement from the doppler shift of a transmission signal. Anoscillator generates an ultrasonic transmission frequency which is transmitted via atransmission plate coupled to the oscillator. A plurality of receivers detect reflections ofthe ultrasonic sound signal and supply the detected signal to a bandpass filter whichpasses the transmission frequency. A low-pass demodulator will detect any dopplersignal which modulates the transmission signal and will supply it to an amplifier foramplification. The amplified signal is then provided to a narrow band filter which will passonly a narrow band of doppler- shift signals which correspond to the frequencies ofhuman movement. The signal is then supplied to a switching means which, when activated,will discharge a first node. The first node is charged via a resistor and a capacitor coupledto a voltage source. A comparator is coupled to the first node and is also coupled to avoltage reference. The comparator will produce an output signal when the first node hasa higher voltage than the voltage reference, thereby enabling a control means which willsupply current to the electric load. The detected doppler signal discharges the capacitorvoltage thus insuring that an output signal is supplied while movement is detected in the
room to keep the electric load supplied with current.
申请人：THE WATT WATCHER, INC.
代理机构：Townsend and Townsend
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