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Experiment # 4: DSB and SSB Modulation Using MATLAB Built-In Commands

This document discusses single sideband (SSB) and double sideband suppressed carrier (DSB-SC) modulation. SSB modulation transmits information using only one sideband, reducing bandwidth by half compared to AM or DSB-SC. DSB-SC modulation suppresses the carrier frequency to minimize wasted power, distributing power between the sidebands. Matlab and Simulink are used to generate SSB and DSB-SC modulated signals. Upper and lower sidebands are also simulated separately. In conclusion, SSB and vestigial sideband modulation require special filters but have improved performance over DSB-SC in terms of power and bandwidth efficiency.

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Junaid Anwar
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620 views12 pages

Experiment # 4: DSB and SSB Modulation Using MATLAB Built-In Commands

This document discusses single sideband (SSB) and double sideband suppressed carrier (DSB-SC) modulation. SSB modulation transmits information using only one sideband, reducing bandwidth by half compared to AM or DSB-SC. DSB-SC modulation suppresses the carrier frequency to minimize wasted power, distributing power between the sidebands. Matlab and Simulink are used to generate SSB and DSB-SC modulated signals. Upper and lower sidebands are also simulated separately. In conclusion, SSB and vestigial sideband modulation require special filters but have improved performance over DSB-SC in terms of power and bandwidth efficiency.

Uploaded by

Junaid Anwar
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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Anaolg & Digtal Communication LAB MANUAL

Name Muhammad Sohaib Choudhary


Reg# 2015-EE-484
Marks/Grade

Experiment # 4

DSB and SSB modulation using MATLAB Built- in commands


Objective:
Use the Simulink to implement the Single side band modulation and Double side band
modulation
SSB Modulation:
The baseband message can be transmitted by using only one of the sidebands and, consequently,
half the bandwidth of AM or DSBSC-AM. This type of modulation is called single-sideband (SSB)
modulation. It has been extensively used in many radio transmission systems and in the telephone
network. The block diagram to generate SSB modulated signal . Translating the frequency spectrum
of a signal is closely related to SSB modulation and is commonly used at various points in
communication systems.

For a filter to be physically realizable, the transmission band separating the pass-band from the stop
band must have a finite width. The band-pass filter demands that there be an adequate separation
between the lower sideband and the upper sideband of the DSB-SC modulated wave produced at
the output of the product modulator

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Anaolg & Digtal Communication LAB MANUAL

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Matlab code:

Output:

Figure 1 single side band graph

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Simulink model:

Output:

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DSB Modulation:
The standard AM modulated signal contains a sinusoidal component at the carrier frequency which
does not convey any of the baseband message information []. This component is included to create
a positive envelope which allows demodulation by a simple, inexpensive envelope detector. From
an information theory point of view, the power in the sinusoidal carrier component is wasted.

The type of modulation that will be studied in this section is called double-sideband suppressed-
carrier amplitude modulation (DSBSC-AM).
Double-sideband suppressed-carrier transmission (DSB-SC) is transmission in which frequencies
produced by amplitude modulation (AM) are symmetrically spaced above and below the carrier
frequency and the carrier level is reduced to the lowest practical level, ideally being completely
suppressed. In the DSB-SC modulation, unlike in AM, the wave carrier is not transmitted; thus,
much of the power is distributed between the sideband, which implies an increase of the cover in
DSB-SC, compared to AM, for the same power used. It is used for radio data systems.

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Matlab code:

Output:

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Simulink model:

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Output:

Upper and Lower side band:


Matlab code:

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Outputs:

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CONCLUSION:
All the simulations have done in Matlab Simulink (R2015a). First DSBSC signal is generated with
different modulating and carrier signal frequencies. Modulating signal, carrier and DSBSC signal
and their spectrum are shown in Fig. From all simulation and Literature surveys it is concluded
that SSB modulated signal and VSB signal requires special filters to one side band and thus
resulting high performance with respect to power and bandwidth.

INSTRUCTOR:SIR.ALI RAZA 12

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