Hi, On Fri, Aug 13, 2010 at 8:28 AM, Olin Lathrop w= rote: > > The tradeoff between random noise attenuation and the step response of a > single pole filter is fixed. =A0No free lunch to be had. =A0However, you = can > significantly decrease the step response at the same random noise > attenuation by cascading multiple filters. =A0This may sound like a free > lunch, but it's not since the computation requirements have gone up. > Fortunately single pole low pass filters are relatively easy to compute, = so > using multiple poles is often a good option. If you have enough CPU available, you can use a proper multi-pole butterworth filter, this web page is good for a simple design, as it gives C code for the filter: http://www-users.cs.york.ac.uk/~fisher/mkfilter/trad.html You can also convert the multi-pole filters to a cascade implementation, to get better stability. Daniel. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .