% invfdemo	demonstrates Inverse Filtering%	Version 2.90%	last revision 24.03.2002%	Copyright (C) 1997-2002 by Alois Schloegl <a.schloegl@ieee.org>% This library is free software; you can redistribute it and/or% modify it under the terms of the GNU Library General Public% License as published by the Free Software Foundation; either% Version 2 of the License, or (at your option) any later version.%% This library 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% Library General Public License for more details.%% You should have received a copy of the GNU Library General Public% License along with this library; if not, write to the% Free Software Foundation, Inc., 59 Temple Place - Suite 330,% Boston, MA  02111-1307, USA.load eeg8s.mat;	    % load signally=length(eeg8s);Fs=128;%a=earpyw(eeg8s',11); % Calculates AR(11) parameters with Yule-Walker methoda=lattice(eeg8s',11); % Calculates AR(11) parameters with Yule-Walker method		    % The AR parameters are the weight taps of IIR Filter	isig=filter([1 -a],1,eeg8s);   % Inverse filteringsubplot(221);plot((1:ly)/Fs,eeg8s);title('Signal');xlabel('t [sec]')subplot(223);plot((1:ly)/Fs,isig);xlabel('t [sec]')title('Inverse filtered process');subplot(222);H=abs(fft(eeg8s,128)/ly).^2;plot(1:Fs,H);%plot([H mean(H)*ones(Fs,1)]);ylabel('S(f)')xlabel('f [Hz]')title('Spectrum of original signal');subplot(224);H=abs(fft(isig,128)/ly).^2;plot(1:Fs,H);%plot([H mean(H)*ones(Fs,1)]);ylabel('S(f)')xlabel('f [Hz]')title('Spectrum of inverse filtered signal');