Ultrasonic signal travel time determination procedure measures phase difference using quadrature demodulation for partial inversion with clock and phase shifted clock signal

摘要

An ultrasonic signal travel time determination procedure measures the phase difference using quadrature demodulation for partial inversion of the received signal using a clock (8) and phase shifted clock (9) and integration with the remainder determined from signal characteristics. Independent claims are included for ultrasonic flow rate sensors using the procedure.