Up and down counting circuit - responds to phase difference between two pulses for count forwards or backwards signal

摘要

The up/down counting circuit responds to the phase difference between two pulses from two pulse trains and accordingly produces either count forwards of count backwards signals. The circuit is cheap to make and is not affected by spurious pulses generated by the unavoidable chatter of any mechanical contacts that may be serving as pulse generator. - One pulse is applied to the set input of a first bistable flip flop (G1, G2) and the other to the set input of a second bistable flip flop (G3, G4). The reset inputs of both flipflops are connected to a pulse generator (K3, S3), which produces a pulse before or after each pair of input pulses. A logic circuit (G5, G6) indicates the states of both flipflops. Count direction signals are derived via a third flip flop (G9, G10) and further logic