Ultrasonic testing of materials - chooses specified signal level and selects signals with amplitudes which exceed predetermined level

摘要

The method consists of transmitting ultrasonic oscillations into the material, reception and processing of reflected oscillations, separation of the signals from interferences on the selected level, and deriving the size of faults. Separation of signals (19-23) from interferences on the chosen level (Uo) is performed by their selection in time intervals (t24-t28) in which the signal (19-23) amplitude exceeds the chosen level (Uo). The circuit forms strobe impulses (24-28) from a pulse forming circuit (15) which are electrically coupled between the output of the pulse circuit and the second input (14) of the AND element.