53 lines
887 B
Matlab
53 lines
887 B
Matlab
% twotone.m
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% David Rowe Aug 2012
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% Used to experiment with combining phase of two tones
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function cbphase
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Wo = 100.0*pi/4000;
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L = floor(pi/Wo);
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phi = zeros(1,L);
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% two harmonics
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a = 20; b = 21;
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% set up phases to whatever
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phi(a) = -pi;
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phi(b) = -pi/2;
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% synthesis the two-tone signal
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N = 16000;
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Nplot = 250;
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s = zeros(1,N);
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for m=a:b
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s_m = cos(m*Wo*(0:(N-1)) + phi(m));
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s = s + s_m;
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endfor
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% now our theory says that this signal should be the same perceptually
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phi_(a) = (phi(a) - phi(b))/2;
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phi_(b) = (phi(b) - phi(a))/2;
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s_ = zeros(1,N);
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for m=a:b
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s_m = cos(m*Wo*(0:(N-1)) + phi_(m));
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s_ = s_ + s_m;
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endfor
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% plot them and see if envelope has the same phase, but "carriers"
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% have different phase
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figure(1);
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clf;
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subplot(211);
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plot(s(1:Nplot));
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subplot(212);
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plot(s_(1:Nplot),'r');
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endfunction
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