Remove of spike/noise in square wave.

Discussion in 'General Electronics Chat' started by whywhy68, Jul 31, 2008.

  1. whywhy68

    Thread Starter Member

    Jun 11, 2008
    my square wave output consisit of a few spike occasionally. anyway to remove the spike/noise ?
  2. mik3

    Senior Member

    Feb 4, 2008
    Use a zener diode and a resistor in a series combination and then in parallel with a small capacitor to absorb the spikes. The diode should turn on fast and the capacitor should have low lead inductance. Also, the RC charging time of the capacitor should be slightly more than the turn on time of the diode as not to be charged at the spike's voltage before the diode turns on.

    Note that the capacitor may affect the shape of the pulses a bit.
  3. Norfindel

    Active Member

    Mar 6, 2008
    Well, a possible solution would be to eliminate the peak at it's source, if possible. Why is it being generated?

    A low pass filter can remove the spikes, but would smooth the square wave, also. That said, it's maybe not a problem to slightly smooth the signal.

    You could use a schmitt trigger gate to restore the signal beautiness. If the spikes won't make the gate to falsely trigger, it can be used alone, or you could need to use the low pass filter, or a combination of both.