Short pulse width noise immunity discriminator circuit

摘要

A circuit is described for discriminating relatively wide, high level signal pulses from relatively narrow and/or low level noise pulses. The input pulses are first passed through a first Schmitt trigger to eliminate low level noise pulses. The output of the first Schmitt trigger is connected to a signal input of a "D" latch and to one input of an exclusive NOR gate. The exclusive NOR gate compares the input pulses from the output of the first Schmitt trigger with an output of the latch through a second Schmitt trigger. An R-C integrating network connected between the exclusive NOR gate and the second Schmitt trigger produces a rising input signal to the second Schmitt trigger that reaches the threshold level of the Schmitt trigger only for input signal pulses that exceed a given pulse width.