[Adaptive FSK] MATLAB Simulation of Adaptive Demodulation of Digital FSK Modulated Signals

1. Software version

MATLAB2013b

2. Theoretical knowledge of this algorithm

3. Core code

NUMS = 20000;
Bits = round(rand(1,NUMS)>=0.5);
f1   = 1;
f2   = 2;
Scale= 50;
t    = 0:1/Scale:1-1/Scale;

As   = 1;

%FSK
Bits0  = sin(2*pi*f1*t);
Bits0  = Bits0/sqrt(sum(Bits0.^2));

Bits1  = sin(2*pi*f2*t);
Bits1  = Bits1/sqrt(sum(Bits1.^2));

fsk    = [];
for i=1:NUMS
    if Bits(i)==1
       fsk=[fsk Bits1];
    else
       fsk=[fsk Bits0];
    end
end

figure
subplot(211)
stairs(0:10,[Bits(1:10) Bits(10)],'linewidth',1.5)
axis([0 10 -0.5 1.5])
title('Message Bits');grid on
subplot(212)
tb=0:1/Scale:10-1/Scale;
plot(tb, fsk(1:10*Scale),'r','linewidth',1.5)
title('FSK调制');grid on
.....................

 4. Operation steps and simulation conclusion

 

 

 

5. References

[1] Fu Baicheng, Zhao Zhijin, Zhao Zhidong. Adaptive demodulation of digital modulated signal under impulse noise [J]. Modern Electronic Technology, 2008, 31(23):5.
A01-499