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DSBSC and AM Signal Generation Lab

The document is an experiment description for a communications lab at Jordan University of Science and Technology. The objectives are to generate an amplitude modulation (AM) signal, a double sideband suppressed carrier (DSB-SC) signal, and analyze the effects of modulation index. The equipment includes a master signal panel, multiplier, adder, variable DC source, and oscilloscope. The experiment involves generating AM signals at different modulation indices to observe the effects on the time and frequency domain signals, and generating a DSB-SC signal where the carrier is highly suppressed.

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16 views5 pages

DSBSC and AM Signal Generation Lab

The document is an experiment description for a communications lab at Jordan University of Science and Technology. The objectives are to generate an amplitude modulation (AM) signal, a double sideband suppressed carrier (DSB-SC) signal, and analyze the effects of modulation index. The equipment includes a master signal panel, multiplier, adder, variable DC source, and oscilloscope. The experiment involves generating AM signals at different modulation indices to observe the effects on the time and frequency domain signals, and generating a DSB-SC signal where the carrier is highly suppressed.

Uploaded by

aboodm20th
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Jordan University of Science and Technology

Faculty of Engineering
Department of Electrical Engineering

Fall semester 2023/2024

EE 452 Communications Lab

Experiment (2): DSBSC Generation, AM Generation

Student Name: ID:

Group Members

Name ID

Instructor:

Section: 1

Date:
DSBSC Generation, AM Generation

1. Objectives

 Generate an amplitude modulation signal in its general form


 Generate a double sideband suppressed carrier signal
 Understand the effects of modulation index on the modulated signal
 Analysis all generated signals in time and frequency domain

2. Equipment and Materials

Master signal panel Multiplier


Adder variable DC
Scope wires

3. Theory

Amplitude modulation (AM) is a modulation technique used in electronic


communication, most commonly for transmitting messages with a radio
wave. In amplitude modulation, the amplitude of the wave (carrier) is varied
in proportion to that of the message signal, such as an audio signal.
In general form, a modulation process of a sinusoidal carrier wave may be
described by the following equation:

S(t) = A [1 + Km(t)] cos (fc*t)


Where m(t) is the message signal, A cos(fc*t) is the carrier signal and A*k is equal
something called modulation index (μ) that indicates how much the m(t) will affect
the c(t).
Vmax−Vmin
μ ¿ Vmax +Vmin
4. the Process
We did four different cases in the experiment:
A. When μ = 1

As we see that the


maximum of the signal in
time domain is equal 4V
and the minimum is equal
to zero which indicate that
Here we see that in
there is full modulation
frequency domain that there
happened
are three main peaks as
expected, the highest is for
the carrier and the other two
for the side bands

Here is the XY plot, we can


clearly see that
Vmin = 0 so the μ = 1

B. When μ < 1

As we see that the


maximum of the signal in
time domain is less that 4V
and the minimum is higher
than zero which indicate
Here we see that in
that there is modulation
frequency domain that there
happened but not 100%
are three main peaks as
expected, the highest is for
the carrier and the other two
for the side bands
Here is the XY plot, we can
clearly see that
Vmin > 0 so the μ < 1
C. When μ > 1

Here we see that is a new thing happened which is over modulation, and we
start to see a new peaks in the modulated signal, and even in the XY plot there
is a difference, actually this plot explain that the C(t) start to suppress.

As mentioned before the


carrier pulse in FD is less
than the sidebands
When μ >> 1

Here we see that we generate a new signal which is a DSB-SC which that the
signal only hold the sidebands as see in XY plot, in this case the AM equation is
a bit different which is a normal multiplication.

S(t) = m(t) * c(t)

As mentioned before the


carrier pulse in FD is almost
suppressed the all the power
of the signal goes to the
sidebands

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