clear
max_bits=30; %maximum number of bits for allowing one to plot the signal and the eye diagram
points=input('enter the number of points per symbol: ');
bits=input('enter the number of bits: ');
p0=input('enter the probability of 0: ');
pulse_type=input('enter the pulse type (0: NRZ; 1:Raised Cosine; 2:Manchester): ');
switch pulse_type
    case 0
        pulse=nrz(points);
    case 1
        alfa=input('enter the Roll Off factor (>0, <=1): ');
        if alfa<=0 || alfa >1
            disp('error');
            return
        end
        intervals=input('enter the number of T intervals for representing the pulse: ');
        pulse=square_root_raised_cosine(alfa,points,intervals);
    case 2
        pulse=manchester(points);        
    otherwise
        disp('error');
        return;
end     
info=2*(rand(1,bits)>p0)-1;
if bits < max_bits
    individuals=input('do you want to build the individual bit signals (0/1)?: ');
else
    individuals=0;
end

if individuals
    for i=1:bits, 
        info1=zeros(1,bits); 
        info1(i)=info(i); 
        x1(i,:)=signal_build(info1,points); 
        xt(i,:)=conv(x1(i,:),pulse);
        yt(i,:)=conv(xt(i,:),pulse); 
    end
    r1=sum(yt,1);
else
    x1=signal_build(info,points);
    xt=conv(x1,pulse);
    r1=conv(xt,pulse);
end
t=(1:length(r1))/points;
    
[a,b]=find(abs(abs(r1)-1)<.01);
if bits < max_bits
    sg=input('plot the signal (0/1)?: ');
else
    sg=0;
end
if sg
    figure;
    plot(t,r1);
    hold on
    for i=1:bits, plot(t(b(1)+(i-1)*points)*ones(1,3),[-2 0 2],'k-.','LineWidth',2); end
    set(gca,'XLim',[t(max(1,b(1)-points)),t(min(b(1)+bits*points,length(t)))]);
end
snrdB=input('enter snr (dB): ');
noisev=10^(-snrdB/10);
noise=randn(1,length(t))*noisev^.5;
r2=r1+noise;
if sg
    plot(t,r2,'r');
end
if bits < max_bits
    eye=input('plot the eye diagram (0/1)?: ')
else
    eye=0;
end
if eye
     ploteye(r1,points,b(1)-points/2,bits)
     title('eye diagram without noise');
     input('press a key to continue')
     ploteye(r2,points,b(1)-points/2,bits)
     title('eye diagram with noise');
end
ber_eva=input('ber evaluation (0/1)?: ');
while ber_eva==1
    offset=input('enter a offset on synchronization: ');
    for i=1:bits, rec_values(i)=r2(b(1)+(i-1)*points+offset)>0; end
    ber=sum(xor(info>0,rec_values))/bits;
    str=sprintf('bers=%.2e bert%.2e\n',ber,1/2*erfc((1/(2*noisev))^.5));
    disp(str);
    ber_eva=input('another offset value (0/1)? ');
end
po_sp=input('plot power spectrum (0/1)? ');
if po_sp
    rl=input('how many realizations? ');
    Rm(1,:)=(abs(fft(r1))).^2;
    for i=2:rl
        info=2*(rand(1,bits)>0.5)-1;
        x1=signal_build(info,points);
        xt=conv(x1,pulse);
        r1=conv(xt,pulse);
        Rm(i,:)=(abs(fft(r1))).^2;
    end
    new_plot=input('new figure (0/1)? ');
    color=input('color (k,b,r,g) value between apexes: ');
    str=sprintf('%1s',color);
    plot_power_spectrum(mean(Rm),points,new_plot,str);
end