kopia lustrzana https://github.com/ha7ilm/csdr
71 wiersze
1.7 KiB
Matlab
Executable File
71 wiersze
1.7 KiB
Matlab
Executable File
#!/usr/bin/octave
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global Tb=20
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function g=gbb(t) %impulse response of pulse shaping filter
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global Tb
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g=t;
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for i = 1:size(t)(2)
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if (t(i)>1*Tb || t(i)<=-1*Tb)
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g(i) = 0;
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else
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g(i) = 0.5+cos((t(i)/(Tb*1))*pi)/2; %this is not RRC, rather a sinusoidal pulse shape
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end
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end
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end
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global padding=[-2 2];
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function [toreturny, plotrange]=y(s)
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global Tb
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global padding
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slen=size(s)(2)
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plotrange=((padding(1)-1)*Tb):(slen+padding(2))*Tb-1;
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plotlen=size(plotrange)(2)
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toreturny=zeros(1,plotlen);
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for i=1:slen %sum of (symbol[i] * filter impulse response) for all symbols
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toreturny+=s(i)*gbb(plotrange.-(i-1)*Tb);
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end
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plotrange=plotrange/Tb
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end
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function fmtplot(h)
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FN = findall(h,'-property','FontName');
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set(FN,'FontName','/usr/share/fonts/truetype/ttf-dejavu/DejaVuSerifCondensed.ttf');
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set(FN,'FontName','times');
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FS = findall(h,'-property','FontSize');
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set(FS,'FontSize',18);
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set(FS,'FontSize',18);
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end
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h=figure(1);
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subplot(2, 1, 1);
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[a b]=y([1]);
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plot(b, a, 'linewidth', 2)
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title(sprintf("Impulse response of pulse shaping filter"))
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xlabel('t/Ts')
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ylabel('h(t)')
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subplot(2, 1, 2);
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[a b]=y([1 1 -1 -1 1 1 1 -1 1 -1 1 1]);
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plot(b, a, 'linewidth', 2)
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title("Baseband signal for modulator input\nbit sequence: 110011101011") %assuming that differential encoding has already been performed
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xlabel('t/Ts')
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ylabel('s(t)')
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xbounds = xlim;
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set(gca,'XTick',xbounds(1):xbounds(2));
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fmtplot(h);
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pause
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exit
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%fourier analisys of baseband signal
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h2=figure(2);
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padding=[-1 1]
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plot(y([1]))
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h3=figure(3);
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fftvals=abs(fft(y([1])));
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sizefftvals=size(fftvals)(2)
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fftvals=[fftvals(sizefftvals/2:sizefftvals) fftvals(2:sizefftvals/2)]
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plot(fftvals, "-")
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pause
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