function e=Low_Mu_e(Fp,Fs)
%  Low_Mu_e.m  計算選擇性系數
%  $date 4/10/2005
%
%   作者：趙澤平
%      vf1983cs@163.com
%   
%
%   References:
%        Miroslav D. Lutovac, Dejan V. Tosic, Brian L. Evans
%           Advanced Filter Design for Signal Processing
%                   Using MATLAB and Mathematica

%% calls: 
e=tan(pi*Fs)/tan(pi*Fp);