How to do Frequency Shift Keying (FSK) using MATLAB

1.Introduction:-

In FSK the modulated signal is shifted in steps that is from one frequency to another frequency depending on the digital pulse.If the higher frequency is used for represent the data '1' then lower frequency is used for represent '0'.

2.Problem Statement:-
To generate the FSK wave using MATLAB and plot the carrier ,square pulse and FSK signal on figure window.


3.Program:-
clc;
clear all;
close all;
t=0:0.0001:1;
fm=4;
m=[ones(1,900) zeros(1,1500) ones(1,1000) zeros(1,1500) ones(1,1000) zeros(1,1500) ones(1,2601)];
subplot(4,1,1);
plot(t,m);
axis([0 1 0 1.5])
title('modulating signal');
xlabel('time');
ylabel('amplitude');
fc1=input('enter the value of carrier 1=');
fc2=input('enter the value of carrier 2=');
c1=4*sin(2*pi*fc1*t);
c2=4*sin(2*pi*fc2*t);
subplot(4,1,2);
plot(t,c1);
title('carrier signal 1');
xlabel('time');
ylabel('amplitude');
subplot(4,1,3);
plot(t,c2);
title('carrier signal 2');
xlabel('time');
ylabel('amplitude');
for i=1:length(m)
    if m(i)==0
        fsk(i)=c1(i);
    else
        fsk(i)=c2(i);
    end
end
subplot(4,1,4);
plot(t,fsk);
title('FSK signal');
xlabel('time');
ylabel('amplitude');


4.How to use this code:-
Here you have to only copy the code to MATLAB and just run after that just enter the value of carrier1 and carrer2 in comand window and press enter.

5.Output :-

 Figure Window  

                                 

Command Window

                                                   



6.Conclusion -
Here we have successfully plot the FSK using the MATLAB.



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