low_mu_le.m

信号处理－滤波器设计（基于matlab和Mathmatica的设计方法）中关于无乘法器椭圆IIR滤波器设计的原创程序。

function e=Low_Mu_Le(n,L)
%  Low_Mu_L.m  已知L，求e
%  $date 4/10/2005
%
%   作者：赵泽平
%      [e-mail]
%   
%
%   References:
%        Miroslav D. Lutovac, Dejan V. Tosic, Brian L. Evans
%           Advanced Filter Design for Signal Processing
%                   Using MATLAB and Mathematica
t=(1-(1-1/L^2)^0.25)/(1+(1-1/L^2)^0.25)/2;
q=t+2*t^5+15*t^9+150*t^13;
g=exp(log(q)/n);
q0=(g+g^9+g^25+g^49+g^81+g^121+g^169)/(1+2*(g^4+g^16+g^36+g^64+g^100+g^144));
e=(1-((1-2*q0)/(1+2*q0))^4)^(-0.5);