I think Richard is eluding to a process called Fast Fourier Transform, FFT for short. The filter is a mathematical equation applied to each result. In many cases, the previous result is part of the equation. FFT is used to filter noise out of cell phone signals, among other things. The magic is getting the FFT formula right for your application. I've looked into it briefly, just enough to get an idea of what it's about, but not enough to actually use it effectively. I do know there are "standard" FFTs that are go-to works-every-time-its-tried that would probably work for you.

The one that is like Example #1 in the textbooks is simply:
Code:
if Result > Previous
 Plot += 1
elseif Result < Previous
 Plot -= 1
endif
Previous = Result
This simply plots trends of increasing or decreasing values, without specific concern for the actual value.