Patent ID: 8700344
Filing Date: 2014-04-15
Classification: G01F

Abstract:
1. A method of measuring a mean time of flight for an ultrasonic signal to travel a given distance in a fluid under zero flow conditions, independent of the rate of flow, if any, of said fluid during said measurement, comprising: Driving a periodic input signal through first and second ultrasonic transducers simultaneously to generate first and second transmitted ultrasonic signals, respectively; While driving said transducers with said input signal, receiving with said first transducer said second transmitted signal, and receiving with said second transducer said first transmitted signal, and measuring a phase relationship between said first received signal and said second received signal, said phase relationship defining a difference signal; Computing said time of flight by dividing the distance between said transducers by the time elapsed between a selected number of cycles of said difference signal, said selected number of cycles corresponding to a frequency of said input signal and the distance between said transducers.