The document presents information on single sideband (SSB) and double sideband (DSB) modulation using a balanced modulator method. It discusses how SSB splits the modulating signal into two identical signals, with one passing through a 90 degree phase shifter before modulating the quadrature carrier. It also explains how DSB suppression works by using two AM modulators with an inverted modulating signal to one, so that subtracting their outputs removes the carrier wave. The document concludes by thanking all the attendees of the presentation.

1. Welcome
To
Our Presentation

2. Presentation Topics
Single Side Band (SSB) & Double
Side Band (DSB) Modulation by
using Balanced Modulator
Method.

3. Presented By
Name
Md. Hassan Al Roktim
Md. Abu Imran
Md. Harun-Ar-Rashid
ID
121-33-893
121-33-859
121-33-879

4. Single Sideband Modulation (SSB):
The modulating signal is split into two
identical signal. Which modulates the phage
carrier and the other which is passed through
a -90˚ phage shifter before modulating
quadrature carrier. The sign used for the
quadrature component determines whether
USB or LSB is transmitted.

5. Balanced Modulator Method

6. Double Sideband Modulation (DSB):
One possible scheme for generating a DSBSC wave is to use two AM
modulators arranged in a balanced configuration so as to suppress the
carrier wave, as shown in above fig. Assume that two AM modulators are
identical, except for the sign reversal of the modulating signal applied to
the input of one of the modulators. Thus the outputs of the two AM
modulators can be expressed as follows:
S1 (t) = Ac [1+ka m(t)] cos 2fct
and
S2 (t) = Ac [1- ka m(t)] cos 2fct
Subtracting S2 (t) from S1 (t), we obtain
S (t) = S1 (t) – S2 (t)
S (t) = 2Ac ka m(t) cos 2fct

7. Balanced Modulator Method:

8. Hence, except for the scaling factor 2ka the balanced modulator output is equal
to product of the modulating signal and the carrier signal
The Fourier transform of s (t) is
S (f) = kaAc [M (f-fc) + M (f+fc)]
Assume that the message signal is band-limited to the interval –W ≤f≤ W

10. THANKS TO ALL