Simple--and inexpensive--logic circuitry is described which will discriminate three types of spike activity in the canine electroenterogram. Used during high-speed replay of tape-recorded myoelectric activity, it provides a numerical analysis of the duration and spike content of the three types of activity, without the need for sophisticated (and costly) computer analysis. The ability of the analyzer to detect types of activity is illustrated by the analysis of the effects of a peptide hormone infusion on the canine electroenterogram. The device might also serve as the prototype for other applications in which simple digital logic could be used to detect different patterns in continous analog signals.