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

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

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Q: In a <strong>UT</strong> test system where signal amplitudes are displayed on a CRT, an<br />

advantage of a frequency-independent attenuator over a continuously<br />

variable gain control is that:<br />

A. the pulse shape distortion is less<br />

B. the signal amplitude measured using the attenuator is independent<br />

of frequency<br />

C. the dynamic range of the system is decreased<br />

D. the effect of amplification threshold is avoided<br />

Q: An amplifier in which received echo pulses must exceed a certain<br />

threshold voltage be<strong>for</strong>e they can be indicated might be used to:<br />

A. suppress amplifier noise, unimportant scatter echoes, or small flaw<br />

echoes which are of no consequence<br />

B. provide a screen display with nearly ideal vertical linearity characteristics<br />

C. compensate <strong>for</strong> the unavoidable effects of material attenuation loss<br />

D. provide distance amplitude correction automatically

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