dfdxmin.m

AFD - Advanced Filter Design using MATLABMiroslav D. Lutovac, Dejan V. Tosicversion 1.00 released 15

function xmin = dfdxmin(n, Kp, Ks)

% dfdxmin.m  DFD Minimum selectivity
%
%   Authors: Dejan V. Tosic, Miroslav D. Lutovac, 1999.03.08
%                 [e-mail]
%                 [e-mail]
%
%   Copyright (c) 1999 by Tosic & Lutovac
%   $Revision: 1.0 $  $Date: 1999/03/08 03:07:42 $
%
%   References:
%        Miroslav D. Lutovac, Dejan V. Tosic, Brian L. Evans
%           Advanced Filter Design for Signal Processing
%                   Using MATLAB and Mathematica

%  calls:
%% dfdqk.m

terms = 9;
L = Ks/Kp;
qL = dfdqk(1/L)^(1/n);
m = 1:terms;
num = 1 + 2*sum((-ones(size(m))).^m.*(qL*ones(size(m))).^(m.^2));
den = 1 + 2*sum((qL*ones(size(m))).^(m.^2));
xmin = 1/sqrt(1 - (num/den)^4);