--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/test/diagnostics/test_ltpda_arma_freq.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,138 @@
+function test_ltpda_arma_freq()
+% A test script for the ltpda_arma_freq function
+% 
+% miquel 25-02-08
+% 
+% $Id: test_ltpda_arma_freq.m,v 1.1 2008/03/04 12:55:05 miquel Exp $
+% 
+
+%% Make test AOs
+
+fs=1;
+nsecs=10000;
+
+pl = plist();
+pl = append(pl, param('nsecs',nsecs));
+pl = append(pl, param('fs',fs));
+pl = append(pl,param('tsfcn','(heaviside(t-1000.5)).*(1-(exp(-(t-1000.5)/300))+(exp(-(t-1000.5)/500)-1))'));
+
+ain = ao(pl);
+
+% Filter input time-series
+pl = append(pl, param('type', 'highpass'));
+pl = append(pl, param('ripple', 5e-1));
+pl = append(pl, param('order', 1));
+pl = append(pl, param('gain', 1e-1));
+pl = append(pl, param('fc', 1e-3));
+
+f = miir(pl);
+[aout, fout] = filter(ain,plist(param('filter',f)));
+
+% Add independent noise to both channels
+pn1 = plist('waveform', 'noise','type','Uniform','fs', fs, 'nsecs', nsecs);
+an1 = ao(pn1);
+
+ain = ain + 1e-4*an1;
+
+pn2 = plist('waveform', 'noise','type','Uniform','fs', fs, 'nsecs', nsecs);
+an2 = ao(pn2);
+
+aout = aout + 1e-4*an2;
+
+
+%% Fourier transform input varialbles
+
+% Initialise variables
+in=ain.data.y;
+out=aout.data.y;
+
+% Fourier Transform
+L=length(in);
+NFFT = 2^nextpow2(L); % Next power of 2 from length of y
+NFFT=length(in);
+
+x_ = fft(in,NFFT)/L;
+y_ = fft(out,NFFT)/L;
+
+x = 2*abs(x_(1:NFFT/2)); % single-sided amplitude spectrum.
+y = 2*abs(y_(1:NFFT/2)); % single-sided amplitude spectrum.
+
+f = fs/2*linspace(0,1,NFFT/2)';
+
+Px=ao(fsdata(f,x,fs));
+Py=ao(fsdata(f,y,fs));
+
+%% Find ARMA parameters for the transfer function
+
+% Parameter list for ltpda_arma_freq
+pl = append(pl, param('MaxIter',1e3));
+pl = append(pl, param('MaxFunEvals',1e3));
+pl = append(pl, param('TolX',1e-7));
+pl = append(pl, param('TolFun',1e-7));
+pl = append(pl, param('ARMANum',2));
+pl = append(pl, param('ARMADen',1));
+
+% Use ltpda_arma_freq
+ao_arma = ltpda_arma_freq(ain, aout, pl);
+%  
+disp(sprintf('\r! Filter parameters:\r')) 
+disp(sprintf('%d\t', fout.a,fout.b(2:length(fout.b))))
+disp(sprintf('\r! Estimated parameters:\r')) 
+disp(sprintf('%d\t',ao_arma.data.y(1:length(ao_arma.data.y)-1)))
+
+%%  Compute fitted output
+p = find(pl, 'ARMANum');
+q = find(pl, 'ARMADen');
+
+% Compute time domain fit
+flt = miir([ao_arma.data.y(1:p)],[1 ao_arma.data.y(p+1:p+q)],find(pl,'fs'));
+[afit, ffit] = filter(ain,plist(param('filter',flt)));
+
+% Compute frequency domain fit
+% [Pfit, Pf] = filter(Px,plist(param('filter',f)));  % problems with ao.filter
+yfit= freqfun([ao_arma.data.y(1:p)],[1 ao_arma.data.y(p+1:p+q)],x,f,fs); % using adhoc function
+Pfit=ao(fsdata(f,yfit,fs));
+
+%  Plot time domain
+iplot(ain,aout,afit,plist('Legends', {'Input','Output','Fit'}))
+
+%  Plot frequency domain
+iplot(Px,Py,Pfit,plist('Legends', {'Input','Output','Fit'}))
+
+
+% Plot history 
+figure
+plot(ao_arma.hist)
+
+%% Reproduce from history
+
+% Write an m-file from AO
+ao2m(ao_arma, 'ltpda_test.m');
+
+% now run it
+clear all;
+a_out = ltpda_test;
+
+% iplot(a_out)
+
+figure
+plot(a_out.hist)
+
+%% Delete test files
+delete('ltpda_test.m');
+
+
+% Compute filter
+function F= freqfun(ps,qs,xdata,f,fs)
+Hnum=0;
+Hden=0;
+for j = 1:length(ps)
+Hnum = Hnum+ps(j)*exp(-(j-1)*i*2*pi*f/fs);
+end
+for j = 1:length(qs)
+Hden = Hden+qs(j)*exp(-(j-1)*i*2*pi*f/fs);
+end
+F=abs(Hnum./Hden).*xdata;
+
+
+