A method for identification of overlapping single echoes: application to NDE tests

A method is proposed for identifying single echoes in a multiple echo which is the sum of overlapping similar echoes. The final aim is to give for each single echo two pertinent items of information: the weighting factor and the time-delay estimate. The model developed is based on the computation of the complex envelope which is derived from the analytic signal associated with the received signal. The model uses information regarding both amplitude and phase variations with regards to time. Experimental signals obtained during NDE tests of a metallic block with artificial defects are used to verify the theoretical model. The results show good agreement with theory