Signal Filtering Basics
jeroendoggen edited this page Dec 25, 2012
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The goal of these filters is cleaning up a noisy signals by suppressing small (fast) signal changes while passing bigger (slow) signal changes. This is done by reducing the "higher frequency" fluctuations.
Linear filter with a maximally flat group delay: http://en.wikipedia.org/wiki/Bessel_filter
Steeper roll-off but more passband ripple: http://en.wikipedia.org/wiki/Chebyshev_filter
A Bandpass filter can also get rid of the DC that you might have in a sensorvalue without need of calibrating (i.e. in calm state, you have +2V, with a signal more or less, the bandpass will give you positive and negative values around).
Filter for noise reduction: http://en.wikipedia.org/wiki/Median_filter