Patent ID: 9448053
Filing Date: 2016-09-20
CPC Classification: A61B,G01B,G01S,G08B

Claim Text:
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.