u_chb2ap.m

很多matlab的源代码

function [b,a] = u_chb2ap(N,As,Omegac)
% Unnormalized Chebyshev-2 Analog Lowpass Filter Prototype
% ----------------------------------------------------------
% [b,a] = u_chb1ap(N,As,Omegac)
% b = numerator polynomial coefficients
% a = denominator polynomial coeffients
% N = Order of the Elliptic Filter
% As = Passband Ripple in dB ; Rp>0
% Omegac = Cutoff frequency in radians/sec
% 
[z,p,k] = cheb2ap(N,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;
b = real(poly(z));
bNu = b(M);
k = k*(aNu*bNn)/(aNn*bNu);
b0 = k;
b = b*k;