For the purpose of analysis, two parameters are often extracted from an ultrasound signal: the time of flight (ToF) and the amplitude, shown on an example waveform in Figure . ToF represents the total travel time of the acoustic wave between its emission from the pulsing transducer and its measurement at a receiving transducer. The amplitude is a measure of the intensity of the voltage output from a piezoelectric transducer and is directly proportional to the pressure on the transducer and its area. The wave maximum or span (maximumminimum) are common metrics for the amplitude.