cheb1hpf.m

很多matlab的源代码

function [b,a] = cheb1hpf(wp,ws,Rp,As)
% IIR Highpass filter design using Chebyhev-1 prototype
% function = cheb1hpf(wp,ws,Rp,As)
% b = Numerator polynomial of the highpass filter
% a = Denominator polynomial of the highpass filter
% wp = Passband frequency in radians
% ws = Stopband frequency in radians
% Rp = Passband ripple in dB
% As = Stopband ripple in dB
%
wplp = 0.2*pi;
alpha = -(cos((wplp+wp)/2))/(cos((wplp-wp))/2);
wslp = angle(-(exp(-j*ws)+alpha)/(1+alpha*exp(-j*ws)));
T = 1;
Fs = 1/T;
OmegaP = (2/T)*tan(wplp/2);
OmegaS = (2/T)*tan(wplp/2);
[cs,ds] = afd_chb1(OmegaP,OmegaS,Rp,As);
[blp,alp] = bilinear(cs,ds,Fs);
Nz = -[alpha,1];
Dz = [1,alpha];
[b,a] = zmapping(blp,alp,Nz,Dz);