In analog communication, DSBSC (double side band suppressed carrier) is way of modulating signal.
In this the carrier is simply multiplied with the message signal.
At the demodulator, the carrier is multiplied back which gives the message signal back.
- The first signal is my message signal
- The second is the modulated signal
- The third is the demodulated signal i.e I can get the msg by simply tracking the peak voltages
Now the demodulation process seems to be complete but the part that I am missing is a low pass filtee at demodulator. Why is it required? I have my signal back. Why should I pass it through a low pass filter? All the books have the filter.
Please explain why the low pass filter is required after the demodulator.
t=0:1e-4:30; f=5; y=sind(2*pi*f*t); subplot(3,1,1) plot(t,y) hold on yline(0) xline(0.2) ylim([-2 2]) hold off subplot(3,1,2) y1=sind(2*pi*100*t); y3=y1.*y; plot(t,y3) hold on yline(0) hold off subplot(3,1,3) y4=y3.*sind(2*pi*100*t); plot(t,y4) hold on ylim([-2 2]) plot(t,y); hold off