1 function baseband(rolloff, M, numSymbs)
2 %% Set defaults for inputs
13 %% https://www.mathworks.com/help/comm/examples/passband-modulation-with-adjacent-channel-interference.html
14 Rsym = 1e6; % symbol rate (sym/sec)
16 span = 6; % filter span
17 sps = 4; % samples per symbol
19 fs = Rsym * sps; % sampling freq (Hz)
21 t = (0 : 1 / fs : numSymbs / Rsym + (1.5 * span * sps - 1) / fs)';
24 EbN0 = 10 .^ (EbN0_db ./ 10);
29 EsN0 = EbN0 .* log2(M);
30 EsN0_db = 10 .* log10(EsN0);
32 plotlen = length(EbN0);
33 ber = zeros(1, plotlen);
35 data = randi([0 M - 1], numSymbs, 1);
36 modData = pskmod(data, M, 0, 'gray');
38 xBaseband = txFilter(modData, rolloff, span, sps);
41 snr = EbN0_db(i) + 10 * log10(log2(M)) - 10 * log10(sps);
42 noiseEnergy = 10 ^ (-snr / 10);
44 yBaseband = awgn(xBaseband, snr, 'measured');
46 rBaseband = rxFilter(yBaseband, rolloff, span, sps);
48 rSampled = rBaseband(sps*span/2+1:sps:(numSymbs+span/2)*sps);
49 demodData = pskdemod(rSampled, M, 0, 'gray');
50 [bitErrors, ber(i)] = biterr(data, demodData);
56 %% Plot simulated results
57 semilogy(EbN0_db, ber, 'r', 'LineWidth', 2);
60 theoreticalPSK(EbN0_db, M, 'b', 'LineWidth', 1);
61 legend('Simulated', 'Discrete');
63 title(strcat(num2str(M), '-PSK with Gray code'));
65 xlabel('$E_b/N_0$ (dB)');