afd_chb1.m

<Matlab 7辅助信号处理技术与应用》的源码

function[b,a]=afd_chb1(Omegap,Omegas,Ap,As)
% 切比雪夫I型模拟低通滤波器设计
% b=G(s)分子多项式的系数
% a=G(s)分母多项式的系数
% Omegap=通带截止频率，rad/s
% Omegap=阻带截止频率，rad/s
% Ap=通带波动的+dB数
% As=阻带波动的+dB数

if Omegap<=0
    error('通带边缘必须大于0')
end
if Omegas<=Omegap
    error('阻带边缘必须大于通带边缘')
end
if (Ap<=0)|(As<=0)
    error('通带波动或阻带衰减必须大于0')
end
ep=sqrt(10^(Ap/10)-1);
A=10^(As/20);
OmegaC=Omegap;
OmegaS=Omegas/Omegap;
g=sqrt(A*A-1)/ep;
N=ceil(log10(g+sqrt(g*g-1))/log10(OmegaS+sqrt(OmegaS*OmegaS-1)));
[b,a]=u_chb1ap(N,Ap,OmegaC);