Clamping digital signal for noise protection

[sean87]

I have a 5V signal which gets some noise because of a nearby coupling (it is hall sensor signal from a  motor and the noise is I beleive the PWM switching into the motor for speed control).

These spikes cause unwanted triggering of commutation. I have an RC filter in place but it does not help. The question is...clamping this using a zener diode would help or not? How can I effectively remove the noise you see in the picture?

[Wimberleytech]

A schematic would certainly help in understanding the fundamental problem here.

[David Hess]

Is it an analog or digital signal?

I do not see how simple clamping will be helpful at all.  Some advanced analog techniques where fast settling is desired use adaptive clamping for lack of a better term.

If the RC filter did not work on your example, then either there is not enough or the noise is actually present somewhere else like the ground.

[vk6zgo]

Don't clamp it, clip it, removing the noise.
You then amplify it to the original level.
This was how it was done in the old days.