Abstract: A method and apparatus is disclosed for calibrating an ultrasonic inspection system having a plurality of transducers (12a, 12b, 12c) coupled by a common amplifier (16) to a distance-amplitude correction (D-AC) circuit comprised of a multiplying digital-to-analog converter (26') which receives, as a function of the transit time of an ultrasonic signal measured by a clock counter (34), a D-AC correction stored in a look-up table in a random access memory (24'). The D-AC correction function stored in the look-up table for each transducer is the inverse of a return signal response curve determined by measuring the peak amplitude of return signals from calibration holes at known depths in a test block (10) while in a calibrate mode, i.e., with a switch (SW) in a state to bypass the MDAC.

Abstract: An ultrasonic inspection system is disclosed having a skate remotely controlled from a main console for positioning an ultrasonic transducer. A transmission line is used to couple drive pulses from the main control console to the transducer. Each drive pulse is generated at the console by timing means for firing a first silicon-controlled rectifier (SCR) to discharge a precharged capacitor into the line, and for firing a second SCR to shunt discharge current from the capacitor to ground. The line is terminated at its input end by its characteristic impedance. The length of the line may be changed without requiring any change at the transducer or the pulse generating circuit, except that the size of the precharged capacitor may be varied to assure delivery of a pulse of desired amplitude to the transducer.