1.问题描述：
FSEDFE
2.部分程序：
% ummse_fse_dfe Designs Unbiased MMSE T/2-spaced feedforward equalizer (FSE)
% and T-spaced decision feedback equalizer (DFE)
% for a T/2-spaced complex FIR channel at a certain
% SNR (dB) of AWGN and a unit power iid source given
% a cursor delay and an optional decision feedback delay.
%
% [f,d,ummse] = ummse_fse_dfe(h,snrdb,Nf,Nd,delta1,delta2)
%
% returns:
% f : FSE
% d : DFE
% ummse : Unbiased Minimum Mean Square Error
% (i.e. design is scaled so that
%