M = 4;
apply_precode = 0;

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

bits = Informationsignal(bitpattern);

symbols = PAMmapper(M,0).map(bits);

bits_rx = PAMmapper(M,0).demap(symbols);
[~,~,ber_direct,~] = calc_ber(bits.signal,bits_rx.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);

if apply_precode
    symbols_tx = Duobinary().precode(symbols);
else
    symbols_tx = symbols;
end

show2Dconstellation(symbols_tx,symbols_tx,"displayname",'VNLE Out','fignum',2241);


if apply_precode
    % 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(symbols_tx);

    % Entschiedene codierte Symbole decodieren: d_dec(n) = d_DB(n) mod4
    symbols_rx = Duobinary().decode(symbols_db);
else
    symbols_rx = symbols_tx;
end

% Vergleichen von b(n) und d_dec(n)
bits_rx = PAMmapper(M,0).demap(symbols_rx);
[~,~,ber,~] = calc_ber(bits.signal,bits_rx.signal,"skip_front",10,"skip_end",10,"returnErrorLocation",1);

disp(['BER: ',sprintf('%.1E',ber),' - - PAM-',num2str(M)]);


figure(200)
clf
hold on
start = 100;
burstwidth = 10;
idxs = start-10:start+burstwidth+10;
scatter(idxs,d.signal(idxs),'DisplayName',['Orig Signal'],'Marker','o');
scatter(idxs,d_burst.signal(idxs),'DisplayName',['Error Signal'],'Marker','x');
scatter(idxs,d_dec.signal(idxs),'DisplayName',['EQ Signal'],'Marker','x');
yline(PAMmapper(M,0).thresholds,'HandleVisibility','off');
legend
ylim([-2 2])