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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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Instrument Circuitry: Receiver-amplifier circuits<br />

electronically amplify return signals from the receiving transducer and often<br />

demodulate or otherwise modify the signals into a <strong>for</strong>m suitable <strong>for</strong> display.<br />

The output from the receiver-amplifier circuit is a signal directly related to the<br />

intensity of the ultrasonic wave impinging on the receiving transducer. This<br />

output is fed into an oscilloscope or other display device.<br />

Instrument Circuitry: Oscilloscope.<br />

Data received are usually displayed on an oscilloscope in either video mode<br />

or radio frequency mode. In video mode display, only peak intensities are<br />

visible on the trace; in the RF mode, it is possible to observe the wave<strong>for</strong>m of<br />

signal voltages. Some instruments have a selector switch so that the operator<br />

can choose the display mode, but others are designed <strong>for</strong> single-mode<br />

operation only

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