u_elipap.m

很多matlab的源代码

function [b,a] = u_elipap(N,Rp,As,Omegac);
% Unnormalized Elliptic Anlog Lowpass Filter Prototype
% ------------------------------------------------------
% [b,a] = u_elipap(N<Rp,As,Omegac)
% b = numerator polynomial coefficients
% a = denomonator polynomial coefficients
% N = Order of the Elliptic Filter
% Rp = Passband Ripple in dB ;Rp>0
% As = Stopband Attenuation in dB;As>0
% Omegac = Cutoff frequency in rad/sec
%
[z,p,k] = ellipap(N,Rp,As);
a = real(poly(p));
aNn = a(N+1);
p = p*Omegac;
a = real(poly(p));
aNu = a(N+1);
b = real(poly(z));
M = length(b);
bNn = b(M);
z = z*Omegac;
bNu = b(M);
k = k*(aNu*bNn)/(aNn*bNu);
b0 = k;
b = k*b;