Microwave motion sensor

  • US 9,448,053 B2
  • Filed: 04/19/2013
  • Issued: 09/20/2016
  • Est. Priority Date: 09/20/2010
  • Status: Active Grant
First Claim
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1. A microwave motion sensor, comprising:

  • a transmitting device transmitting a microwave signal to a space under detection;

    a receiving device receiving a reflected microwave signal reflected from the space under detection;

    a signal processing device processing the reflected microwave signal received by the receiving device to judge whether there is a disturbance in the space under detection, wherein the signal processing device generates the microwave signal; and

    a delay path switching device coupled to the signal processing device and the transmitting device, wherein the delay path switching device switches a plurality of transmission paths having different delays and results in different phase shifts to the transmission paths which the microwave signal passes through,wherein,the signal processing device at least comprises a dual-control voltage-controlled oscillator, which generates the microwave signal;

    the signal processing device compares the microwave signal with a reference signal to obtain a first control voltage, which reflects an external disturbance information of the space under detection;

    an oscillation frequency of the dual-control voltage-controlled oscillator is determined by the first control voltage and a second control voltage; and

    wherein, in response to the dual-control voltage-controlled oscillator being affected by the external disturbance information and results in a DC offset to the first control voltage, the signal processing device generates a second voltage variation of the second control voltage according to a first voltage variation of the first control voltage to eliminate the DC offset of the first control voltage by the dual-control voltage-controlled oscillator.

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