%DEMO_ADAPTLOOP  Show the effect of adaptation
%
%   This script demonstrates the effect of adaptation applied to a test
%   signal with and without noise.
%
%   The test signal is made of a sinosoidal ramp up and down between 0
%   and 1.
%
%   Figure 1: Clean test signal
%
%      This figure shows the effect of adaptation on the clean test signal with and
%      without overshoot limiting.
%
%   Figure 2: Noisy test signal
%
%      This figure shows the effect of adaptation on the noisy test signal
%      with and without overshoot limiting. Notice that in the second plot,
%      the initial spike at the beginning of the signal caused from the sharp
%      transition from complete silence to noise is magnitudes larger than
%      the values in the rest of the output.
%
%   See also: adaptloop
%
%   Url: http://amtoolbox.org/amt-1.6.0/doc/demos/demo_adaptloop.php


%   #Author: Peter L. Soendergaard (2013)

% This file is licensed unter the GNU General Public License (GPL) either 
% version 3 of the license, or any later version as published by the Free Software 
% Foundation. Details of the GPLv3 can be found in the AMT directory "licences" and 
% at <https://www.gnu.org/licenses/gpl-3.0.html>. 
% You can redistribute this file and/or modify it under the terms of the GPLv3. 
% This file is distributed without any warranty; without even the implied warranty 
% of merchantability or fitness for a particular purpose. 


fs=10000;
siglen=4500;
part=siglen/6;

insig=[zeros(part,1); rampup(part); ones(2*part,1); rampdown(part); zeros(part,1)];
x=(0:siglen-1)/fs;

figure;
subplot(2,1,1);
plot(x,20*log10(insig+eps));
title('Input signal (clean)');
ylabel('Level (dB)');
axis([xlim -100 0]);

subplot(2,1,2); hold on;
plot(x,adaptloop(insig,fs,0));
plot(x,adaptloop(insig,fs),'r');
legend({'No overshoot limit','With overshoot limit'});
ylabel('Level (model units)');
xlabel('Time (s)');
axe=axis;

% Add a low level of noise
insig=abs(insig+0.001*randn(siglen,1));

figure;
subplot(2,1,1);
plot(x,20*log10(insig+eps));
title('Input signal (with Gaussian noise)');
ylabel('Level (dB)');
axis([xlim -100 0]);

subplot(2,1,2); hold on;
plot(x,adaptloop(insig,fs,0));
plot(x,adaptloop(insig,fs),'r');
legend({'No overshoot limit','With overshoot limit'});
ylabel('Level (model units)');
xlabel('Time (s)');
axis(axe);