DEPTH RESOLUTION BY MEANS OF ULTRASONIC SIGNALS PROCESSING TECHNIQUES

SUMMARY In order to solve the problem of detection of small flaws near the surface of the piece to be controlled, several methods have been developped at U.T.C. We present here one of these methods which exploits a relatively delicate parameter, the spectral phase of the echographic signal. Then we compare the results obtained with the ones given by two other methods : a spectral substitution method and a method which consists to excite the transducer with an optimal signal giving the shortest possible echographic response.