x=randi([1 0],1,10);
n= 0:9;
j=0;
for i=1:length(x);
j=j+i;
if x(i)==0 && x(i+1)==0
y(j)=0;
else if x(i)==0 && x(i+1)==1
y(j)=1;
else if x(i)==1 && x(i+1)==1
y(j)=2;
else if x(i)==1 && x(i+1)==0
y(j)=3;
end
end
end
end
end
t = 0:0.001:5-.01;
T = 0:0.01:0.99;
f1 = sin(2*pi*T);
f2 = sin(8*pi*T);
f3 = sin(16*pi*T);
f4 = sin(32*pi*T);
figure()
stairs(n,x), axis([0 9 -2 2]), grid on
%FSK modulation
for a=1:length(y)
if y(a)==0
signal(a*100-99:a*100)=f1;
else if y(a)==1
signal(a*100-99:a*100)=f2;
else if y(a)==2
signal(a*100-99:a*100)=f3;
else if y(a)==3
signal(a*100-99:a*100)=f4;
end
end
end
end
end
figure(2)
plot(t,signal), axis([0 5 -2 2]), grid on;