4 %% https://www.mathworks.com/help/comm/examples/passband-modulation-with-adjacent-channel-interference.html
5 Rsym = 2.5e10; % symbol rate (sym/sec)
7 span = 6; % Tx/Rx filter span
8 rolloff = 0.25; % Tx/Rx RRC rolloff
9 sps = 4; % samples per symbol
12 fs = Rsym * sps; % sampling freq (Hz)
15 t = (0 : 1 / fs : numSymbs / Rsym + (1.5 * span * sps - 1) / fs)';
18 data = randi([0 M - 1], numSymbs, 1);
19 modData = pskmod(data, M, 0, 'gray');
20 x = txFilter(modData, rolloff, span, sps);
22 %% Simulate chromatic dispersion
23 D = 20; % ps / (nm km)
27 [xCD, xCDkstart] = chromaticDispersion(x, D, lambda, z, Tsamp);
28 xCD = normalizeEnergy(xCD, numSymbs, 1);
34 yCDComp = CDCompensation(y, D, lambda, z, Tsamp);
36 %% Compare original signal and compensated signal
41 plot(real(yCDComp(1:300)));
44 legend('original', 'dispersion compensated');
48 plot(imag(yCDComp(1:300)));
53 r = rxFilter(yCDComp, rolloff, span, sps);
54 r = normalizeEnergy(r, numSymbs, 1); % Add noise energy if needed
56 rSampled = r(sps*span/2+1:sps:(numSymbs + span/2) * sps);
59 title('Constellation of original modulation');
60 scatterplot(rSampled);
61 title('Constellation of sampled received waveform');
63 demodData = pskdemod(rSampled, M, 0, 'gray');