Explain about the working of functional units in ultrasonic pulse echo system.

The master timer by the electronic clock triggers the signal pulse generator at ordinary intervals. Then signal generator sends a little burst of high frequency alternating voltage to the transducer. The transducer produces pulse of ultrasonic waves. That sound energy propagates by the inspection piece. While there is a discontinuity as like crack in the wave path, part of energy is reflected back through the flaw surface.

The reflected pulse causes the acquiring transducer element to vibrate inducing alternating electrical voltage across the transducer. That induced voltage is immediately amplified and fed to display device (CRO). Initially while the master timer triggers the signal pulse generator, concurrently this activates linear time base circuit of the display device (CRO). Therefore in CRO, the reflected signal strength versus the time is exhibits.