Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

The approximate relations shown in Figure (6) above, can be used to assist in
transducer selection. For example, if a -14 dB waveform duration of one
microsecond is needed, what frequency transducer should be selected?
From the graph, a bandwidth of approximately 1 to 1.2 MHz corresponds
to approximately 1 microsecond -14 dB waveform duration. Assuming a
nominal 50% fractional bandwidth transducer, this calculates to a nominal
center frequency of 2 to 2.4 MHz. Therefore, a transducer of 2.25 MHz or
3.5 MHz may be applicable.
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