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Course: EEE 307 Experiment# 1

Section:02

Name of the experiment:Amplitude Modulation (DSBSC).

Group: 05

1. Mustafa 2008-3-80-011

2. Khondoker Fazle Rabbi 2009-1-80-020

3. Subir Sarker 2009-1-80-023

4. Md. s!ail "ossain 2009-1-80-038

Submitted to: Shar!in R. #raSubmission Date: 0$.02.2011

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Objeti!e"

The objective of this experiment is to get familiar with the wave shape of a double sideband

suppressed carrier !S"SC# $% modulated signal.

Blo Dia$%am"

Fi%ure 1& DSBSC modulated signal generator.

Mustafa2008-3-80-011

Report:

!ata from time domain

&ea' (alue )re*uenc+

%essage signal, mt# -/0 m( 1.2/3 456

Carrier signal, ct# -2/-.7 m( 22 456

%odulated signal, ut# --8.7 m( 02.89 456

!ata from fre*uenc+ domain$mplitude )re*uenc+

f#;upper side band 2.92d" 21.1456

f#;lower side band 2.3-d" 09.3456

Q/As :

http://upload.wikimedia.org/wikipedia/en/9/90/DSBSC_Modulation.svg

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. %$T

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0 0.005 0.01 0.015 0.02 0.025 0.03-10

-5

0

5

10

time, t

messagesignal,m(t)

m(t) vs t plot

0 0.005 0.01 0.015 0.02 0.025 0.03-500

0

500

time, t

modulatedsignal,u(t)

u(t) vs t plot

-. Bn !S";SC $mplitude modulation the fre*uenc+ content of the modulated signal ut# in

the fre*uenc+ band fDfc is called the upper sideband of f#, and the fre*uenc+ content

in the fre*uenc+ band ffc is called the lower sideband of f#. Either one of the

sidebands of f# contains all the fre*uencies that are in %f#. Since f# contains both

the upper and the lower sidebands, it is called a double;sideband!S"# $% signal. The

other characteristics of the modulated signal ut# is that it does not contain a carrier

component. This is evident from observing the spectrum of f#. $s long as mt# does not

have an+ !C component, there is no impulse in f# at f=fccarrier fre*uenc+#,which

would be the case if a carrier component was contained in the modulated signal ut#. )or

this reason, ut# is called a suppressed;carrier signal. Therefore modulated signal is called

!S";SC $% signal.

1. Bn cases where we want transmit less power from transmitter there using of !S";SC is

advantageous. "ecause in !S";SC signal there is no power component of the carrier.

/. Bf the adder in the diagram was connected then it becomes a Conventional !S" $%.

7. Bn this experiment we learnt how to use lab module to setup !S";SC $%. Fe also learnthow to ta'e reading from picoscope for various parameter of a signal.

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Khondoker Fazle Rabbi2009-1-80-020

Sou%e"Fi'ipedia, Google, Communication S+stems Engineering, Continuous and !iscreteSignals and S+stems.

Name Peak to Peak (mV) Frequency (k!)C(t) "#$% #&&m(t) "''$ .&%u(t) "*" %&.+%

&ame $mplitude d"# )re*uenc+ '56#

S" 2.9 21.1

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4.

/2 t,e adder is connected t,ere -ill be anot,er comonent multilied -it, t,emodulated signal.

'.

3,is e4eriment ,els us to get 2amiliar -it, t,e -a1e s,ae o2 a doublesideband suressed carrier (DSBSC) 56 modulated signal.

Md. s!ail "ossain2009-1-80-038