ON OFF Keying (OOK) MATLAB Code

This page provides MATLAB source code for ON OFF Keying (OOK) modulation. The output plots and mathematical equations relevant to the code are discussed below.

Introduction to ON OFF Keying

ON OFF Keying (OOK) is a digital modulation technique where the amplitude of a carrier signal is varied according to a digital binary stream.

In OOK modulation, a carrier signal with a certain amplitude is transmitted when a binary logic ‘1’ is present. Conversely, no carrier transmission occurs when a binary logic ‘0’ is present.

Figure 1: OOK modulation waveforms at inputs and output.

ON OFF Keying MATLAB Code

clear all
close all
tic
x = [1 0 0 0 0 0 0];
l = length(x);
sp = input('The Speed of Transmission for the Data');
d = input('The Number of data points you want to transmit');
lq = input('The number of times you want to transmit the data');
filat = input('Do you want to use a filter in this transmisssion, if yes press 1');
duty = input('What is the duty Ratio you want to use for the RZ pulse, must be less than 1');
i = 0;
while (j < (2^l - 1))
    y = xor(x(6),x(7));
    temp = [y,x];
    x = temp;
    j = length(x);
end
data(1:d) = zeros;
while(i<d)
    dgen(i+1:i+j) = x;
    i = length(dgen);
    if (i>d)
        data(1:d) = dgen(1:d);
        clear dgen temp
        t = (1/(32*sp))*(1:1:(32*d));
    end
end

% Pulse Generation
% NRZ, RZ
nr(1:32) = ones;
rz(1:32) = zeros;
lo = nearest(duty*32);
rz(1:lo) = ones;
data2 = kron(data,nr);
data3 = kron(data,rz);
subplot(2,1,1),plot(t,data2);hold grid minor
subplot(2,1,2),plot(t,data3);hold grid minor

datt2(1:d) = zeros;
datt3(1:d) = zeros;

if (filat == 1)
    [B,A] = besself(5,0.8*10^9*2*pi);
    [NUMd,DENd] = bilinear(B,A, 32*10^9);
    datat2 = filter(NUMd,DENd,data2);
    datat3 = filter(NUMd,DENd,data3);
else
    datat2 = data2;
    datat3 = data3;
end
subplot(2,1,1),plot(t,datat2,'-r'); grid minor
subplot(2,1,2),plot(t,datat3,'-r'); grid minor

h = waitbar(0,'Error Computation');
BER1(1:lq,1:10) = zeros;
BER2(1:lq,1:10) = zeros;
for rep = 1:lq
    for SNR = 1:10;
        Pn2 =(sum(datat2.^2)/(length(datat2)))* 1*10^(-SNR/20);
        Pn3 =(sum(datat3.^2)/(length(datat3)))* 1*10^(-SNR/20);
        dat2 = datat2+(Pn2*randn(1,length(datat2)));
        dat3 = datat3+(Pn3*randn(1,length(datat3)));
        j = 0;
        i =1;
        lent = length(datat2);
        while(j<=lent-1)
            if(dat2(j+16)<0.5)
                datt2(i) = 0;
            else
                datt2(i) =1;
            end
            if(dat3(j+nearest(lo/2))<0.5)
                datt3(i) = 0;
            else
                datt3(i) =1;
            end
            j = j+ 32;
            i = i+1;
        end
        BER1(rep,SNR) = mean(data~=datt2)/length(data);
        BER2(rep,SNR) = mean(data~=datt3)/length(data);
        waitbar((SNR+((rep-1)*10))/(10*lq),h);
    end
end
close(h)
BER1x = sum(BER1(1:lq,:))/lq;
BER2x = sum(BER2(1:lq,:))/lq;
figure(2),semilogy(BER1x); hold
semilogy(BER2x,'-r');
toc

Input and Output

After unzipping the downloaded folder, run the ONOFFKEyingModulation.m file. You will be prompted to provide the following inputs:

Figure: Input prompts for the MATLAB code

After providing the inputs and pressing “ENTER,” you will obtain the following output MATLAB images:

Figure: OOK modulation output - Part 1

Figure: OOK modulation output - Part 2