useprbs = 1;
M = 8;
randkey = 1;
%%%%% PRBS Generation in correct shape for Modulation Format %%%%%%
O = 18; %order of prbs
N = 2^(O-1); %length of prbs
[~,seed] = prbs(O,1); %initialize first seed of prbs
bitpattern=[];

if useprbs
    for i = 1:log2(M)
        [bitpattern(:,i),seed] = prbs(O,N,seed);
    end
else
    s = RandStream('twister','Seed',randkey);
    for i = 1:log2(M)
        bitpattern(:,i) = randi(s,[0 1], N, 1);
    end
end

if M == 6
    bitpattern = reshape(bitpattern,[],1);
    bitpattern = bitpattern(1:end-mod(length(bitpattern),5));
end

Tx_bits = Informationsignal(bitpattern);

Symbols_tx = PAMmapper(M,0).map(Tx_bits);
Symbols_tx.fs = fsym;

% Symbols = Duobinary().precode(Symbols_tx);

Symbols = Duobinary().encode(Symbols_tx);

% Symbols.spectrum("displayname","db","fignum",12)

Symbols = Duobinary().feedbackdetector(Symbols);

% Symbols.eye(fsym,M);

% Symbols = Duobinary().decode(Symbols);

Rx_bits = PAMmapper(M,0).demap(Symbols);

[~,error_num,ber,error_pos] = calc_ber(Tx_bits.signal,Rx_bits.signal,"skip_front",0,"skip_end",1,"returnErrorLocation",1);

disp(['BER: ',sprintf('%.1E',ber),' - - PAM-',num2str(M)]);
% 
figure;hold on
stairs(Rx_bits.signal(1:100,1),'LineWidth',2)
stairs(Tx_bits.signal(1:100,1),'LineStyle',':','LineWidth',2);

figure;hold on
stairs(Symbols_tx.signal(1:100,1),'LineWidth',2)
stairs(Symbols.signal(1:100,1),'LineStyle',':','LineWidth',2);