MATLAB Code of Single Sided Band Modulation and Demodulation.

[chughtai134]

i want the code of SSB modulation and Demodulation.'
anyone help me....

 

[chughtai134]

i have made this after all by myself ... some help from some respectful source....
here it is ...

%Single SideBand Modulation
%By Naveed Ahmad Chughtai

N = 1024;
fs = 2048;
ts = 1/fs;
%t = (0:ts:1);
t=(0:N-1)/fs;
fc = 600; %Carrier frequency !! Limit fc<800 to avoid freqdomain aliasing
fm1 = 200;
Em1 = 1;

m = Em1*cos(2*pi*fm1*t); %Message
mh = Em1*cos((2*pi*fm1*t)-pi/2); %Hilbert transform of the message signal


sbu = m.*2.*cos(2*pi*fc*t) - mh.*2.*sin(2*pi*fc*t); %Expression for USB SSB
sbl = m.*2.*cos(2*pi*fc*t) + mh.*2.*sin(2*pi*fc*t); %Expression for LSB SSB

SBU = 2/N*abs(fft(sbu)); %Fourier Transform of USB SSB
SBL = 2/N*abs(fft(sbl)); %Fourier Transform of LSB SSB

freq = fs * (0 : N/2) / N;

close all;
figure(2)
subplot(221);
plot(10*t(1:200),sbu(1:200),'r');%Time Domain Plot of USB SSB
title('Time Domain Representation === USB');
xlabel('Time'); ylabel('Modulated Signal');
subplot(222)
plot(10*t(1:200),sbl(1:200),'b');%Time Domain Plot of LSB SSB
title('Time Domain Representation === LSB');
xlabel('Time'); ylabel('Modulated Signal');

subplot(223);
plot(freq,SBU(1:N/2+1))
title('Frequency Domain Representation');
xlabel('Frequency(Hz)'); ylabel('Spectral Magnitude');
legend('USB');
subplot(224)
plot(freq,SBL(1:N/2+1)); %Frequency domain plot
title('Frequency Domain Representation');
xlabel('Frequency(Hz)'); ylabel('Spectral Magnitude');
legend('LSB');

figure(4)
plot(freq,SBU(1:N/2+1),freq,SBL(1:N/2+1));
title('Frequency Domain Representation');
xlabel('Frequency(Hz)'); ylabel('Spectral Magnitude');
legend('USB','LSB');


%Demodulation:

md=sbu.*cos(2*pi*fc*t);
[b,a]=butter(2,0.1);
mf=filter(b,a,md);
figure(3)
plot(t,mf)
title('Demodulated Signal');
xlabel('Time'); ylabel('Demodulated Signal');

figure(1);
plot(t,m);
title('Time Domain Representation of Orignal Signal');
xlabel('Time'); ylabel('Original Signal');