Ultrasonic test appts. with CRT display - has variable width and position controls to select region for study

摘要

Ultrasonic impulses transmitted to a workpiece by a sound transducer (US) give rise to echo signals which are converted to HF electrical signals and fed to a main amplifier (HV). The amplified signals are fed by way of a variable attenuator (ST1) to a switched attenuator (ST2) which has been calibrated, and thence to a further amplifier (V) and rectifier (G). The rectified output controls the Y-deflection of a CRT display. Adjustable position and width controls (M1, M2) are provided for the display, and these are controlled by a clock pulse generator (TG). It is possible to select a desired display region and to vary selectively the attenuation applied to specific echo signals in order to investigate faults in a predetermined position in the test object.