Paper title: PULSE AMPLIFIER USED IN ULTRASONIC NONDESTRUCTIVE TESTING
Author(s): PAUL ION, BOGDAN CRISTIAN FLOREA,
Abstract: The metal ultrasonic nondestructive testing by the echo-pulse procedure uses short ultrasonic pulses generated by a piezoelectric
transducer in contact with the metal, both immersed in water. Short, high amplitude controlled energy electric pulses are
furnished to the transducer and converted into short ultrasonic pulses which penetrate the examined material. After
propagation through the material, they are reflected by the opposite surface or by the material internal discontinuities and are
received by the same transducer which converts them, again, into electric echo-signals. Measuring the ultrasonic pulse round
trip duration and supposing the same wave speed through the material is precisely known, the material dimensions and the
discontinuities positions will be accurately determined. An algorithm correcting the errors due to the signal phase change on the
transducer-material interface ensures an accuracy of 10–5 in dimension measurement in applications where high precision and
sensitivity are asked, without using delay circuits or other procedures specific to such measurements.
The nondestructive ultrasonic testing equipment consists in a pulse generator exciting a piezoelectric transducer, an echo-pulse
amplifier and a time interval measuring system.
In this paper, an echo pulse amplifier is presented, which is characterized by a variable 2–80 dB gain, a distortion factor
δ < 0.8 %, a signal-to-noise ratio < 1 % adapted to the impedance of a 17 MHz, spherically focalized ultrasonic transducer used
for metallic tubes wall thickness measurement.
Keywords: Non-destructive testing, Pulse amplifier, Ultrasounds Year: 2017 | Tome: 62 | Issue: 1 | Pp.: 68-71
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