BANDPASS ADC SAMPLING FOR FLUID VELOCITY DETERMINATION

摘要

A method of calculating a time difference is disclosed. The method includes receiving a first ultrasonic signal (r21) having a first frequency from a first transducer (UT2) at a first time and receiving a second ultrasonic signal (r12) having the first frequency from a second ultrasonic transducer (UT2) at a second time. The first ultrasonic signal and the second ultrasonic signal are sampled at a second frequency (302). The first sampled ultrasonic frequency is interpolated (306). The difference in travel time between the first and second ultrasonic signals is calculated in response to the interpolated first sampled ultrasonic signal and the sampled second ultrasonic signal (equation [43]).