Digital trigger circuit with excellent noise suppression Available to Purchase

The digital trigger circuit described in this paper allowed us to trigger digital data acquisition equipment accurately. Its main feature is a noise suppression circuit which introduces only a small phase shift and permits us to reject noise very close to the frequency range of the measured signal. The level of the rejected noise signal as well as the trigger level are adjustable with thumbwheel switches. The performance of the trigger circuit is demonstrated with a disturbed sine wave as input signal. An analog equivalent circuit with noise rejection characteristics similar to those of the pseudo‐filter is described.