Electronic circuit for eliminating chatter

Claim 1

An electronic circuit for eliminating from at least two input switches the effect of contact bounce, comprising a first group of a first and a second switch means each having two input circuits and one output circuit whereby upon an identical input signal appearing on said two input circuits an output signal exists on said output circuit, first circuit means connecting each of the two input switches providing an input signal to one of said two input circuits of said first and second switch means, a source of timing pulses connected to the other of said two input circuits of said first and second switch means, a second group of a third and fourth switch means each having two input circuits and one output circuit whereby upon an identical input signal appearing on said two input circuits an output signal exists on said output circuit, second circuit means connecting each of said one output circuits of said first and second switch means to one of said input circuits of said third and fourth switch means, third circuit means connecting said source of timing pulses to a second of said two input circuits of said third and fourth switch means, fifth and sixth switch means having two input circuits and an output circuit whereby upon an input signal appearing on each of said two input circuits an output signal exists on said output circuit, fourth circuit means connecting said output circuit of said first and third switch means to one of said input circuits of said fifth switch means and said output circuit of said second and fourth switch means to said input circuits of said sixth switch means, a seventh switch means having at least three input circuits and an output circuit whereby upon identical input signals appearing on all three input circuits, an output signal exists on said output circuit, fifth circuit means connecting said output circuits of each of said fifth and sixth switch means to a first and second input circuits of said seventh switch means and said source of timing pulses to a third input circuit of said seventh switch means, a third group of an eighth and ninth switch means each having two input circuits and an output circuit, whereby upon an identical input signal appearing on each of said two input circuits an output signal exists on said output circuit, and means connecting said output of each of said third and fourth switch means to one of said input circuits of said eighth and ninth switch means respectively and said output circuit of said seventh switch means to each of the other input circuits of said eighth and ninth switch means to provide an output signal at said output circuits of said eighth and ninth switch means indicative of the input signal of the input switches after the contact bounce of the two input switches has terminated.