% (binary_eye.m)
% this program uses the four different pulses to generate eye diagrams of
% binary polar signaling
clear all; close all; clc;
data=sign(randn(1,400)); % generate 400 random bits
Tau=64; % define the symbol period
for i=1:length(data)
    dataup((i-1)*64+1:i*64)=[data(i),zeros(1,63)];% Generate impluse train
end
% dataup=upsample(date,Tau);% Generate impluse train
yrz=conv(dataup,prz(Tau));% Return to zero polar signal
yrz=yrz(1:end-Tau+1);
ynrz=conv(dataup,pnrz(Tau));% Non-return to zero polar
ynrz=ynrz(1:end-Tau+1); 
ysine=conv(dataup,psine(Tau)); % half sinusoid polar
ysine=ysine(1:end-Tau+1); 
Td=4; % truncating raised cosine to 4 periods
yrcos=conv(dataup,prcos(0.5,Td,Tau));% rolloff factor=0.5
yrcos=yrcos(2*Td*Tau:end-2*Td*Tau+1);% generating RC pulse train
eye1=eyediagram(yrz,2*Tau,Tau,Tau/2);title('RZ eye-diagram');
eye2=eyediagram(ynrz,2*Tau,Tau,Tau/2);title('NRZ eye-diagram');
eye3=eyediagram(ysine,2*Tau,Tau,Tau/2);title('Half-sine eye-diagram');
eye4=eyediagram(yrcos,2*Tau,Tau);title('Raised-cosine eye-diagram');