Patent ID: 7637171
Filing Date: 2009-12-29
Classification: G01F

Abstract:
1. An ultrasonic flow sensor, comprising at least one ultrasonic converter for ultrasonic signals selected from the group consisting of an ultrasonic converter for transmitting ultrasonic signals an ultrasonic converter for receiving ultrasonic signals, and an ultrasonic converter for transmitting and receiving ultrasonic signals; an excitation unit connected with said ultrasonic converter; an evaluation unit ascertaining a phase shift of a received ultrasonic signal relative to a parameter selected from the group consisting of a reference signal and a reference value, said evaluating unit including a plurality of quadrature demodulators which operate with different demodulation frequencies and each ascertain phase information about the ultrasonic signal that was received, and which includes a vernier unit that ascertains based on associated phase angles, a phase shift to be determined or a quantity proportional thereto.