figure(2)
tiledlayout(1,3)
cols = linspecer(5);
cnt = 1;
for m = [4,6,8]

    M = m;
    fsym = 112e9;
    fdac = 256e9;
    
    [Digi_sig,Symbols,Tx_bits] = PAMsource(...
        "fsym",fsym,"M",M,"order",19,"useprbs",1,...
        "fs_out",fdac,...
        "applyclipping",0,"clipfactor",1.5,...
        "applypulseform",0,"pulseformer",NaN,...
        "randkey",33,...
        "db_precode",1,"db_encode",0,...
        "mrds_code",0,"mrds_blocklength",512).process();
    
    Symbols_pre = Duobinary().precode(Symbols);
    
    Symbols_db = Duobinary().encode(Symbols_pre);
    
    if M == 4
        Symbols_db.signal = Symbols_db.signal .*sqrt(2.5);
    elseif M == 6
        Symbols_db.signal = Symbols_db.signal .*sqrt(5.8);
    elseif M == 8
        Symbols_db.signal = Symbols_db.signal .*sqrt(10.5);
    end
    
    % figure(1)
    % hold on
    % histogram(Symbols_db.signal,"EdgeAlpha",0.3,"Normalization","probability");
    
    
    % figure(1)
    nexttile
    hold on
    bar(unique(Symbols_db.signal),histcounts(int32(Symbols_db.signal),"Normalization","probability"),"FaceColor",cols(cnt,:),"FaceAlpha",0.6,"BarWidth",1-(0.2*cnt),"LineWidth",0.5,"EdgeColor",'black','DisplayName',['Duobinary PAM-',num2str(M)]);
    xticks(unique(Symbols_db.signal));
    ylim([0 0.26]);
    xlabel("Symbol")
    

    cnt = cnt+1,

end