A threshold monitor test point is provided on each channel to permit accurate and reproducible threshold settings using an external DC voltmeter. Output durations are continuously adjustable from 5 ns to us and are highly stable and independent of input amplitude, duration, and rate. N I M current source outputs and one complementary output. The flexibility resulting from this doubling of the output fan-out capability over previous circuits permits simpler and more efficient logic design. This greatly increased fan-out is achieved by means of a new output circuit design that utilizes very little quiescent power.
L is almost a factor of two lower than that of the most sensitive previous circuits.
It will permit experimenters to routinely reverse-terminate photomultiplier anodes. This procedure, coupled with the greatly improved input termination characteristics of the 621 L, greatly reduces the possibility of multiple-pulsing due to reflections in the input system. Output falltimes slightly longer on wide output durations.