| 摘要 |
The invention relates to an ultrasonic monitoring device for determining the movement direction and/or the movement speed of an object, comprising an ultrasonic transmitter and an ultrasonic receiver, wherein, during the operation of the ultrasonic monitoring device, the ultrasonic transmitter emits an ultrasonic signal, the emitted ultrasonic signal is reflected at an object and the ultrasonic receiver receives the reflected ultrasonic signal, characterized by a clock generator for generating a first clock signal and a second clock signal, wherein the first clock signal and the second clock signal have a predetermined phase difference, a first demodulator for demodulating the received ultrasonic signal, wherein the first demodulator is activated or deactivated depending on the state of the first clock signal and outputs a first output signal, a second demodulator for demodulating the received ultrasonic signal, wherein the second demodulator is activated or deactivated depending on the state of the second clock signal and outputs a second output signal, and an evaluation unit for determining the movement direction and/or the movement speed of the object on the basis of the first output signal and the second output signal. |
