function fp=Low_Mu_fp(f3dB,Fs)
%  Low_Mu_fp  計算fp
%  $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: 
fp=atan(tan(pi*f3dB)^2/tan(pi*Fs))/pi;