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8449f934 AIL |
1 | function baseband(rolloff, M, numSymbs) |
2 | %% Set defaults for inputs | |
3 | if nargin < 3 | |
4 | numSymbs = 1000; | |
5 | end | |
6 | if nargin < 2 | |
7 | M = 2; | |
8 | end | |
9 | if nargin < 1 | |
10 | rolloff = 0.5; | |
11 | end | |
12 | ||
8449f934 AIL |
13 | %% https://www.mathworks.com/help/comm/examples/passband-modulation-with-adjacent-channel-interference.html |
14 | Rsym = 1e6; % symbol rate (sym/sec) | |
15 | ||
16 | span = 6; % filter span | |
17 | sps = 4; % samples per symbol | |
18 | ||
8449f934 AIL |
19 | fs = Rsym * sps; % sampling freq (Hz) |
20 | ||
21 | t = (0 : 1 / fs : numSymbs / Rsym + (1.5 * span * sps - 1) / fs)'; | |
22 | ||
8449f934 AIL |
23 | EbN0_db = 0:0.2:10; |
24 | EbN0 = 10 .^ (EbN0_db ./ 10); | |
25 | Es = 1; | |
26 | Eb = Es / log2(M); | |
27 | N0 = Eb ./ EbN0; | |
28 | ||
29 | EsN0 = EbN0 .* log2(M); | |
30 | EsN0_db = 10 .* log10(EsN0); | |
31 | ||
32 | plotlen = length(EbN0); | |
33 | ber = zeros(1, plotlen); | |
34 | ||
35 | data = randi([0 M - 1], numSymbs, 1); | |
36 | modData = pskmod(data, M, 0, 'gray'); | |
37 | ||
1eeb62fb | 38 | xBaseband = txFilter(modData, rolloff, span, sps); |
8449f934 AIL |
39 | |
40 | for i = 1:plotlen | |
1eeb62fb | 41 | snr = EbN0_db(i) + 10 * log10(log2(M)) - 10 * log10(sps); |
8449f934 AIL |
42 | noiseEnergy = 10 ^ (-snr / 10); |
43 | ||
44 | yBaseband = awgn(xBaseband, snr, 'measured'); | |
45 | ||
1eeb62fb | 46 | rBaseband = rxFilter(yBaseband, rolloff, span, sps); |
8449f934 AIL |
47 | |
48 | rSampled = rBaseband(sps*span/2+1:sps:(numSymbs+span/2)*sps); | |
8449f934 | 49 | demodData = pskdemod(rSampled, M, 0, 'gray'); |
8449f934 AIL |
50 | [bitErrors, ber(i)] = biterr(data, demodData); |
51 | end | |
52 | ||
1eeb62fb | 53 | figure(1); |
8449f934 AIL |
54 | clf; |
55 | ||
56 | %% Plot simulated results | |
57 | semilogy(EbN0_db, ber, 'r', 'LineWidth', 2); | |
58 | hold on; | |
59 | ||
1eeb62fb AIL |
60 | theoreticalPSK(EbN0_db, M, 'b', 'LineWidth', 1); |
61 | legend('Simulated', 'Discrete'); | |
8449f934 AIL |
62 | |
63 | title(strcat(num2str(M), '-PSK with Gray code')); | |
64 | grid on; | |
65 | xlabel('$E_b/N_0$ (dB)'); | |
66 | ylabel('BER'); | |
67 | ||
68 | formatFigure; | |
8449f934 | 69 | end |