diff aim-mat/modules/usermodule/pitchstrength/reduce_tilt.m @ 4:537f939baef0 tip

various bug fixes and changed copyright message

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/aim-mat/modules/usermodule/pitchstrength/reduce_tilt.m	Tue Aug 16 14:37:17 2011 +0100
@@ -0,0 +1,43 @@
+function sig=reduce_tilt(sig,options)
+
+
+plot_switch=1;
+
+lowpassfactor=100;	% relationship between Samplefrequency and lowpassfrequency
+
+% shift all values that are zero at the beginning to the first
+% positive value. This makes the lowpass continuous for high
+% frequencies
+sr=getsr(sig);
+stip=getvalues(sig);
+
+indx=find(stip>0);
+if ~isempty(indx)
+	first_non_zero=stip(indx(1));
+	stip(1:indx(1))=first_non_zero;
+	stip=[ones(200,1)*first_non_zero;stip];
+end
+s=signal(stip,sr);
+s=reverse(s);
+s2=lowpass(s,sr/lowpassfactor);
+diff=s-s2;
+
+% s2=getpart(s2,0,getlength(sig));
+
+
+if plot_switch
+	figure(4)
+	clf
+	plot(s);
+	hold on
+	plot(s2,'r');
+	plot(diff,'g')
+	axis([0 getnrpoints(sig) min(diff)-10 max(sig)+10]);
+end
+
+diff=getpart(diff,0,getlength(sig));
+diff=reverse(diff);
+
+
+% return value
+sig=diff;
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