Discrimination between ultrasonic echo signals within the same time window

Ultrasonic interrogation of multi-layer systems often results in echo signals that are at approximately the same time but which originate at different layers. The problem addressed in this paper is to discriminate between such signals in order to identify the signal of interest. ne basic solution approach introduced here is to systematically perturb the field and discriminate between signals based on differences in amplitude variations of the signals. Simulation and experimental results are presented to demonstrate implementation of the approach for a two-layer system.