Lowpass & Highpass Filter Recipes

[Alex Matulich <alex@xxxxxxxxxxxxxx>]

To all who are interested, and know how to copy mathematical
formulas into computer code:

I have completed compiling the recipes and test results for
Butterworth, Bessel, and Critically-Damped filters, both low-pass
and high-pass.  Step-by-step calculations are available at

   http://unicorn.us.com/trading/2polefilters.html

EasyLanguage source code that implements ALL of these filters in a
single function is at

   http://unicorn.us.com/trading/src/_filter2pole.txt

It's unbelievable how little information exists to construct a
general-purpose Bessel filter with an arbitrary cutoff.  I had to
learn how to derive that one myself.

-- 
  ,|___    Alex Matulich -- alex@xxxxxxxxxxxxxx
 // +__>   Director of Research and Development
 //  \ 
 // __)    Unicorn Research Corporation -- http://unicorn.us.com