Return base filter coefficients of Butterworth filter (= low pass filter with w_cut = 1 rad/s)
function Butterworth import Modelica.Constants.pi; extends Modelica.Icons.Function; input Integer order(min = 1) "Order of filter"; input Boolean normalized = true "= true, if amplitude at f_cut = -3db, otherwise unmodified filter"; output Real cr[mod(order, 2)] "Coefficient of real pole"; output Real c0[integer(order / 2)] "Coefficients of s^0 term if conjugate complex pole"; output Real c1[integer(order / 2)] "Coefficients of s^1 term if conjugate complex pole"; end Butterworth;