Noise and distortion in transient waveform recorders

A data-acquisition system that measures transient waveform recorder (TWR) performance and has self-test capability is described. It uses an HP9836 desktop computer with 2 megabytes of RAM storage, a 30-megabyte hard disc and two floppy discs, a ten-bit TWR interfaced on an HPIB interface, and a CAMAC crate capable of housing up to four 12-bit 20-MHz TWRs. A sinewave curve-fit test, used to evaluate the total noise from all measurement sources and arrive at a parameter called `effective bits´, is described. The results of a Fourier transform performed on the sinusoid used in the curve-fit are also presented. A chief objective of all these measurements was to establish the sensitivity, linearity, and noise characteristics of these devices under various conditions, as well as to establish the dynamic performance characteristics of various analog-to-digital converters to be used in the lidar atmosphere sensing equipment (LASE) experiment