afd_chb2.m

来自「MATLAB信号处理扩展函数,用于信号处理的扩展函数」· M 代码 · 共 18 行

function [b,a]=afd_chb2(Wp,Ws,Rp,As);Chebyshev 2型模拟低通滤波器原形设计
         if Wp<=0
             error('Passband edge must be larger than 0')
         end
         if Ws<=Wp
             error('Stop band edge must be larger than Passband edge')
         end
         if (Rp<=0)|(As<0)
             error('PB ripple edge must be larger than Passban edge')
         end
            ep=sqrt(10^(Rp/10)-1);
            A=10^(As/20);
            OmegaC=Wp;
            OmegaR=Ws/Wp;
            g=sqrt(A*A-1)/ep;
            N=ceil(log10(g+sqrt(g*g-1))/log10(OmegaR+sqrt(OmegaR*OmegaR-1)));
            fprintf('\n***chebyshev-2 filter Order=%2.0f\n',N)
            [b,a]=u_chb2ap(N,As,Ws);