910486f536
- Implemented a new MATLAB script for partial response symbol mapping using Duobinary precoding. - Added functions for printing constellation bit mapping and partial response state tables. - Created a minimal example for an IM/DD system, including signal generation, modulation, and equalization processes. - Integrated various components such as pulse shaping, optical modulation, and receiver processing. - Included detailed configurations for parameters like bias, link length, and filter settings.
78 lines
2.8 KiB
Matlab
78 lines
2.8 KiB
Matlab
for M = [2 4 8]
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bits = Signalgenerator("form", signalform.prms,"M", M,"order", 16).process();
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mapper = PAMmapper(M,0);
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symbols = mapper.map(bits);
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db = Duobinary();
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pr1 = Partialresponse();
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symbols_pre = db.precode(symbols);
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symbols_db = db.encode(symbols_pre);
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symbols_rx = db.decode(symbols_db);
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bits_rx = PAMmapper(M,0).demap(symbols_rx);
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[~,~,ber,~] = calc_ber(bits.signal,bits_rx.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);
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disp(['Class BER: ',sprintf('%.1E',ber),' - PAM-',num2str(M)]);
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symbols_pre_pr = pr1.precode(symbols,"M",M);
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symbols_db_pr = pr1.encode(symbols_pre_pr,"M",M);
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symbols_rx_pr = pr1.decode(symbols_db_pr,"M",M);
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bits_rx_pr = mapper.demap(symbols_rx_pr);
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[~,~,ber_pr,~] = calc_ber(bits.signal,bits_rx_pr.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);
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disp(['Partialresponse BER: ',sprintf('%.1E',ber_pr),' - PAM-',num2str(M)]);
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pre_match = isequaln(symbols_pre.signal, symbols_pre_pr.signal);
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enc_match = isequaln(symbols_db.signal, symbols_db_pr.signal);
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dec_match = isequaln(symbols_rx.signal, symbols_rx_pr.signal);
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pre_maxdiff = max(abs(symbols_pre.signal - symbols_pre_pr.signal));
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enc_maxdiff = max(abs(symbols_db.signal - symbols_db_pr.signal));
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dec_maxdiff = max(abs(symbols_rx.signal - symbols_rx_pr.signal));
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disp(['Precode match: ',num2str(pre_match), ...
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' | max abs diff: ',sprintf('%.3g',pre_maxdiff)]);
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disp(['Encode match: ',num2str(enc_match), ...
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' | max abs diff: ',sprintf('%.3g',enc_maxdiff)]);
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disp(['Decode match: ',num2str(dec_match), ...
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' | max abs diff: ',sprintf('%.3g',dec_maxdiff)]);
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disp('---');
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f = figure("Name",sprintf("PAM-%d Partial-Response Histograms",M));
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t = tiledlayout(f,1,4,"TileSpacing","compact","Padding","compact");
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title(t,sprintf("PAM-%d Symbol Histograms",M));
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nexttile;
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plotDiscreteHistogram(symbols.signal,sprintf("PAM-%d",M));
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nexttile;
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plotDiscreteHistogram(symbols_db_pr.signal,"Duobinary 1st Order");
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nexttile;
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plotDiscreteHistogram(getEncodedSymbols(symbols,M,2),"Duobinary 2nd Order");
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nexttile;
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plotDiscreteHistogram(getEncodedSymbols(symbols,M,3),"Duobinary 3rd Order");
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end
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function y = getEncodedSymbols(symbols, M, order)
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pr = Partialresponse("order",order);
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y = pr.encode(pr.precode(symbols,"M",M),"M",M).signal;
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end
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function plotDiscreteHistogram(x, plot_title)
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levels = unique(x(:)).';
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counts = zeros(size(levels));
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for idx = 1:numel(levels)
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counts(idx) = sum(abs(x - levels(idx)) < 1e-12);
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end
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bar(levels, counts, 0.9, "FaceColor", [0.2 0.45 0.75], "EdgeColor", "none");
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grid on;
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box on;
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xlabel("Level");
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ylabel("Count");
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title(plot_title);
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xticks(levels);
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end
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