+++ Changes +++

+ duobinary_target now supports memoryless decoding (FFE targets DB response without MLSE)
+ PAMmapper.quantize now supports custom constellations for quantization
+ Added a new folder 'Documentations' for pdfs, slides, etc.
+ Added new FSO evaluation scripts in projects/FSO transmission/Evaluation Scripts
+ Added ffe_db (rudimentary module, not important anymore)

projects/db_minimal_example.m

@@ -0,0 +1,71 @@
+% einstellungen
+M = 2;
+apply_precode_at_tx = 0;
+
+% daten erzeugen
+bitpattern = [];
+s = RandStream('twister','Seed',1);
+for i = 1:log2(M)
+    N = 2^(17-1); %length of prbs
+    bitpattern(:,i) = randi(s,[0 1], N, 1);
+end
+
+if M == 6
+    bitpattern = reshape(bitpattern',[],1);
+    bitpattern = bitpattern(1:end-mod(length(bitpattern),5));
+end
+
+tx_bits = Informationsignal(bitpattern);
+tx_symbols = PAMmapper(M,0).map(tx_bits);
+
+if apply_precode_at_tx
+
+    % Precode
+    tx_symbols_precoded = Duobinary().precode(tx_symbols);
+    % Entschiedene Symbole codieren: d_DB(n) = d(n) + d(n-1)    (im Fall von PAM4 7 level [0 1 2 3 4 5 6])
+    symbols_db = Duobinary().encode(tx_symbols_precoded);
+    % Entschiedene codierte Symbole decodieren: d_dec(n) = d_DB(n) mod4
+    rx_symbols = Duobinary().decode(symbols_db);
+    bits_rx = PAMmapper(M,0).demap(rx_symbols);
+
+    figure(1)
+    clf
+    hold on
+    stairs(tx_symbols.signal(1:100),'DisplayName','Tx Symbols','LineStyle','-','LineWidth',2);
+    stairs(rx_symbols.signal(1:100),'DisplayName','Rx Symbols','LineStyle',':','LineWidth',1);
+    legend
+    ylim([-2 2])
+
+
+    [~,~,ber,~] = calc_ber(tx_bits.signal,bits_rx.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);
+    disp(['BER: ',sprintf('%.1E',ber)]);
+    assert(ber == 0)
+else
+
+
+    % Entschiedene Symbole codieren: d_DB(n) = d(n) + d(n-1)    (im Fall von PAM4 7 level [0 1 2 3 4 5 6])
+    symbols_db = Duobinary().encode(tx_symbols);
+
+    % Entschiedene codierte Symbole decodieren: d_dec(n) = d_DB(n) mod4
+    rx_symbols = Duobinary().decode(symbols_db);
+    bits_rx = PAMmapper(M,0).demap(rx_symbols);
+
+    % ref symbole precoden:
+    tx_symbols_ref = Duobinary().encode(tx_symbols);
+    tx_symbols_ref = Duobinary().decode(tx_symbols_ref);
+    tx_bits_ref = PAMmapper(M,0).demap(tx_symbols_ref);
+
+    % step plot to check visually if symbols overlap
+    figure(1)
+    clf
+    hold on
+    stairs(tx_symbols_ref.signal(1:100),'DisplayName','Tx Symbols','LineStyle','-','LineWidth',2);
+    stairs(rx_symbols.signal(1:100),'DisplayName','Rx Symbols','LineStyle',':','LineWidth',1);
+    legend
+    ylim([-2 2])
+
+
+    [~,~,ber,~] = calc_ber(tx_bits_ref.signal,bits_rx.signal,"skip_front",1,"skip_end",1,"returnErrorLocation",1);
+    disp(['BER: ',sprintf('%.1E',ber)]);
+    assert(ber == 0)
+end