Single Side Band (SSB) Modulation and Demodulation using MATLAB
Last Updated :
06 Jun, 2022
Single sideband (SSB) modulation might be a sort of modulation used to send data, which includes an audio signal. Amplitude modulation produces an output signal in which the bandwidth is two times the most frequency of the original baseband signal. SSB modulation neglects this bandwidth increase, and also the power wasted on a carrier, at the price of more device complexity and tougher tuning at the receiver side.
Figure: Block Diagram of Modulation
Figure: Spectrum
The Expression for Single Side Band with Upper Side Band :
here,
m is the cosine wave with time duration of ‘t’,
fc is the carrier frequency,
t is the time duration and
mh s the Hilbert transform of baseband.
Example:
MATLAB
fc = 200;
fm = 30;
fs= 4000;
t = (0 : 1 / fs :1 );
t = linspace(0, 1, 1000);
m = cos(2 * pi * fm * t);
mh = imag(hilbert(m));
sb = m .* cos(2 * pi * fc * t) - mh .* sin(2 * pi * fc * t);
em = sb.*m;
[ n,w ] = buttord(2/1000,4/1000, .5, 5);
[ a,b ] = butter(n,w, 'low' );
dem = filter(a,b,em);
figure;
plot(t, sb);
title( 'Single SideBand Modulation' );
xlabel( 'Time(sec)' );
ylabel( 'Amplitude' );
figure;
plot(t, em);
title( 'Single SideBand Demodulation' );
xlabel( 'Time(sec)' );
ylabel( 'Amplitude' );
figure;
plot(t, dem);
title( 'Filtered Signal' );
xlabel( 'Time(sec)' );
ylabel( 'Amplitude' );
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Output:
Demodulated Signal
Filtered Signal
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