olin_piclist@embedinc.com (Olin Lathrop) wrote:
> Mike Hord wrote:
> > Median filter?  Take, say, 5 samples, put them in increasing order
> > from least to greatest, then take sample 3.
> 
> That still can't gurantee no bounces from sample to sample.

You can always come up with a series of samples to defeat any filter.

A median-value filter is a fairly standard approach to this problem.
It tends to preserve the underlying signal "waveform" fairly well while
filtering out glitches that are less than half the filter length. Its
primary drawback is the delay it introduces -- half the filter length,
just like any other symmetric FIR filter.

Since the implementation involves a sorting operation instead of a dot
product (multiply-add), it is well suited to smaller processors with no
hardware multiplier.

-- Dave Tweed
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