Pulse-echo B/A measurement using variable amplitude excitation

A pulse-echo technique for B/A measurement that requires only one transducer operating at the fundamental frequency is demonstrated. The medium is excited with a progressively increasing amplitude level, and the B/A is computed from the deviation from linearity in the transducer-output voltage. An approximate 3-D formulation has been developed which predicts the behavior of finite-amplitude waves in nonlinear media. This formulation provides the basis for the B/A computation. This theory is presented and illustrated by a number of simulations. Experiments at 3.5 MHz are described and demonstrated by preliminary results from single echoes from a perfect reflector and multiple echoes in B-mode