Abstract: In a circuit for producing output pulses which correspond to pre-selected voltage pulses occurring in an input signal train; means connected to derive from said input signal train a succession of unidirectional pulses, at least some of which pulses occur in time coincidence with the leading and trailing edges of said pre-selected voltage pulses; means including a one-shot multi-vibrator connected to receive said unidirectional pulses and produce a first series of pulses having a uniform duration less than the duration of said pre-selected voltage pulses, means including a bi-stable multi-vibrator connected to receive and produce from said first series of pulses a second series of pulses equal to one half the number of pulses in said first series occurring in a given time interval, and means including a discriminator circuit connected to receive said first and second series of pulses and derive a third series of pulses which corresponds to said pre-selected voltage pulses occurring in said input signal train.

Abstract: 1.