7. Signal Acquisition and Processing
I was invited here to come to talk about transducers, and I'd like to tell you how that came about. It came about because the General Electric Jet Engine Dept. has been trying to perform water immersion ultrasonic inspection of engine forgings with commercially available inspection equipment and has found that this equipment is ill suited to the task. I would guess that most of these instruments were designed 5 or 10 years ago for applications in the steel industry. In any case, they do not have enough dynamic range to accommodate the large acoustic attenuation encountered in Jet Engine alloys, and they do not have adequate resolution. But above all, it seems to be impossible to purchase reliable transducers whose characteristics are reproducible and well specified.
Tiemann, J. J., "A Practical Approach to Fabricating Ideal Transducers" (1977). Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE, July 1975–September 1976. 17.