Patent ID: 8218395
Filing Date: 2012-07-10
Classification: G01S,G08B,H03D

Abstract:
1. A moving object detecting apparatus, the apparatus comprising: an oscillation unit for oscillating at a certain frequency; a transmitting unit for radiating an ultrasonic wave based on a transmission signal outputted from the oscillation unit into a monitoring space; a receiving unit for receiving a reflective wave as a ultrasonic wave reflected from an object present in the monitoring space to output a reception signal; a phase detection circuit for mixing reference signals each having the same frequency as that of the transmission signal and a different phase from that of the transmission signal with the reception signal and for obtaining a pair of Doppler signals each having an amplitude depending on a phase difference from the reference signal, each of the Doppler signals having a different phase from each other; a rotation angle calculation unit for calculating a rotation angle at which a vector having the origin as a starting point and a numerical value of an amplitude level of the pair of Doppler signals as an ending point in a two-dimensional orthogonal coordinate system rotates with time; a cumulative addition unit for accumulating the rotation angle calculated by the rotational angle calculation unit; and a comparison unit for comparing the accumulated value of the rotation angle accumulated by the cumulative addition unit with a threshold value, wherein a single ultrasonic vibrator is common to the transmitting unit and the receiving unit.