The invention discloses a method and device for eliminating
signal noise, the device includes a backward-forward counter and a
signal output circuit; the method for eliminating
signal noise has the following steps: 1) setting valid and invalid level counting thresholds; 2) receiving the signal with signal
noise needed to be eliminated by the backward-forward counter and beginning to count; when the rising edge of each
clock arrives, if the signal is an valid electrical level, adding one on the current counting value, otherwise subtracting one; and the counting value does not increase / decrease until it reaches to a valid / invalid level counting threshold; meanwhile, the signal output circuit outputs signal without noise according to the counting value: when the rising edge of each
clock arrives, if the counting value is a valid / invalid level counting threshold, then outputting valid / invalid level; if the counting value is between the valid and invalid level counting threshold, keeping the output equal to the output of the previous
clock. The device provided by the invention can thoroughly eliminate wide noise, stably output signal without noise, and which is simple to be realized, thereby improving reliability of the
system.