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Journal of Clinical Engineering: July-August 1993

Methods of electrophysiologic analysis, including the continuous and simultaneous monitoring of evoked potentials, are of greatest importance either in clinical practice or in experimental research. This type of analysis calls for both flexibility (the stimulus or the interstimulus can be deterministic as well as random, and the signal on each channel can be sampled at a different rate to minimize the cost of the digitized information) and fast line scanning so that all channels are scanned by the minimum time between two successive samples of input signals. To achieve these two objectives, a powerful, general purpose, compact, flexible electronic system that is cost effective has been designed for electrophysiological investigations. The characteristics of the system (STAD) are as follows: 1) It is modular with 32 maximum analog channels per module (two 16–channel submodules). 2) A host computer initializes the system by menu and reads the measurement data under interrupt or DMA control. 3) Each channel can be selected either by program or by an external clock that is either deterministic or random, and only the selected lines will be served. The evoked potential is sampled for an assigned time period starting from either the stimulus end or following a suitable time interval after the same stimulus. The minimum and maximum channel scanning times are 50 ns and 300 ns, respectively. These scanning time values comply with even the most severe timing requirements for the acquisition of evoked potentials.

©1993Aspen Publishers, Inc.