SYSTEMS AND PROCESSING ALGORITHMS FOR ULTRASOUND TIME-OF-FLIGHT DIGITIZER SYSTEMS

摘要

A method and apparatus for tracking variations in distance D calculated from time-of-flight measurements of a sequence of pulses of a pressure wave oscillation from a transmitter to a receiver identifies a state of synchronous operation by obtaining at least two time-of-flight measurements (20, 22) derived from successive pressure wave pulses which satisfy given synchronicity criteria. Successive time-of-flight measurements are then monitored to identify a shifted time-of-flight measurement (26) which varies by at least half of the wave period from a preceding time-of-flight measurements. The distance D calculated from the shifted time-of-flight measurement is then corrected by the product of the shift factor and the pressure wave wavelength.