findheadtail.m

ADSL经典仿真程序

%MING DING created on 10/07/2002
%find head part and tail part of channel impulse response, saved in reverse order
%Algorithm: Katleen paper on Per Tone.

% Copyright (c) 1999-2003 The University of Texas
% All Rights Reserved.
%  
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%  
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%  
% The GNU Public License is available in the file LICENSE, or you
% can write to the Free Software Foundation, Inc., 59 Temple Place -
% Suite 330, Boston, MA 02111-1307, USA, or you can find it on the
% World Wide Web at http://www.fsf.org.
%  
% Programmers:	Ming Ding
% Version:      %W% %G% 10/07/2002
% 
% The authors are with the Department of Electrical and Computer
% Engineering, The University of Texas at Austin, Austin, TX.
% They can be reached at [e-mail].
% Guner Arslan is also with the Embedded Signal Processing
% Laboratory in the Dept. of ECE, http://signal.ece.utexas.edu.

function [Chiv, L, K] = findHeadTail(channel,win_len)
LC = length(channel);

delay=0;
eng_win=0;

for i=1:(LC-win_len+1)
	tmp = sum(channel(i:i+win_len-1).^2);
	if (tmp >= eng_win)
		eng_win = tmp;
		delay = i-1;
	end
end

K = delay;
L = LC - delay -1;

Chiv = flipud(channel);