lab report pam

8/19/2019 Lab Report PAM

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Pulse Amplitude Modulation

I.

INTRODUCTION

Pulse-amplitude modulation (PAM), is a

form of signal modulation !ere t!e

message information is en"oded in

t!e amplitude of a series of signal pulses.

It is an analog pulse modulation s"!eme in

!i"! t!e amplitudes of a train of "arrier

pulses are #aried a""ording to t!e sample

#alue of t!e message signal. Demodulation

is performed $% dete"ting t!e amplitudele#el of t!e "arrier at e#er% s%m$ol period

&'

T!e "on#ersion of analog signals into

digital signals is di#ided into se"tions

important t!at is* &+

'. ampling

Is t!e pro"ess of sampling of t!e signal

information to $e pro"ess. -reuen"%

signal a""ording to t!e rules of N%uist

sampling is + fm, fm is t!e information

signal to $e sampled. &+

+. /uanti0ing

Is t!e aard of a signal t!at !as $een

sampled $% $ringing t!e signal on t!e

aard of $inar% $its reuired. &+

. 1n"oding

Is a pro"ess of "!anging t!e $inar% "odeinto o$2e"t "ode in a""ordan"e it! t!e

appli"ation of t!e "orresponding digital

signals. &+

At a sampling pro"ess "an $e done $%

using to t%pes of signals, namel% a pulse

or impulse. PAM modulation signal is a

signal to t!e digiti0ation pro"ess in t!e

form of a pulse signal input.

PAM signal formation in t!e digitali0ation pro"ess using pulse represents a first step

$% means generates a signal pulse of t!e

pulse generator to ad2ust t!e pulse idt!

(To) is dis"rete. 3ut t!en it s!ould $e

understood t!at in fa"t form a PAM signal

is generated is*

• ignal PAM is s!aped dis"rete on

time and "ontinuous le#el region

•

ignal PAM s!ape is not purel%analog signals and digital signals are not

pure form &+

II. 1/UIPM1NT

4 Analog "ommuni"ation module

4 Poer suppl%

4 -un"tion generator (it! seep option)

4 Os"illos"ope

Page | 1

PU51 AMP5ITUD1 MODU5ATIONMu!ammad Mui00uddin 3in 6ainol A$idin (7'+'+'7+8')

Mo!d Noor -ai0 3in A$dul Ra!im (7'+'+'7+77)




III. PROD1CUR1

'.

+.

.

9.

7.

:.

PU51 AMP5ITUD1 MODU5ATION

In t!e imulin; MAT5A3, Pulse

Amplitude Modulation need to $e

"onstru"t $ased on t!e -igure '.

Original signal (inus <a#e) and "onstant

need to $e sum and "onne"t to "ope' and

o$ser#ed t!e a#e as s!on in -igure .

Pulse =enerator ill $e "onne"ted to"ope+ and o$ser#ed t!e a#e as s!on in

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-igure 9 t!is ill $e ampling ignal.

Pulse =enerator !ad to $e set in t!e

parameter period (se"s) as s!on -igure +.

et t!e period for pulse generator to >.+7

se"s

3ot! of t!e signals (Original signal and

ampling signal) ill $e multiple $% using

Produ"t $lo"; and "onne"t to "ope. T!e

result of t!e multipli"ation ill produ"e

Pulse Amplitude Modulation (PAM) as

s!on in t!e -igure 7.

Repeat t!e steps and "!ange t!e period for

pulse generator to >.'+7 se"s and '.+7 se"s

and o$ser#ed t!e "ope, "ope' and

"ope+ to "ompare t!em.

I?. R1U5T

Figure 2: Pulse Generator Parameters (0.25 secs)

Figure 3: Original Signal

Figure 4: Sampling Signal

Figure 5: PAM Signal

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Figure 6: Pulse Generator Parameter (0.25 secs!

Figure ": Original Signal

Figure #: Sampling Signal

Figure $: PAM Signal

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Figure 0: Pulse Generator Parameter (.25 secs!

Figure : Original Signal

Figure 2: Sampling Signal

Figure 3: PAM Signal

?. ANA5@I

-rom t!e data "olle"ted, t!e stud% found

t!at if fm is ;0 and fs B ;0, t!e "ut off

freuen"% of t!e lo pass filter t!at

demodulates s PAM signal s!ould $e

slig!tl% a$o#e fm. <!en t!e N%uist rate

is 9 ;0 !i"! is to times of + ;0

message signal freuen"%. o t!e P

freuen"% is greater t!an t!e N%uist rate.

-or t!e imulin; of pulse analog

modulator, if t!e $and limitation is not too

se#ere t!en t!e tet message "an $e

re"o#ered $% "!oosing t!e rig!t t!res!old

$eteen $inar% > and ' and $% sele"ting

t!e rig!t time instants for sampling t!e

Page | 5




PAM signal. 3ut if t!e $and limitation is

strong enoug! to "reate inters%m$ol

interferen"e (II), t!en an in#erse filter

ma% !a#e to $e used to euali0e t!e

"!annel $efore t!e tet message "an $ere"o#ered.

?I. CONC5UION

In s!ort, PAM is a general signaling

te"!niue !ere$% pulse amplitude is used

to "on#e% t!e message. PAM pulses "ould

$e t!e sampled amplitude #alues of an

analogue signal. To main t%pe of PAM

in"ludes natural PAM and flat top PAM. In

order to "on#ert analog to digital signal

using PAM, t!e signal !as to undergo

pro"esses su"! as sampling, uanti0ation

and $inar% en"oding.

?II. R1-1R1NC1

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& 5e"turer Notes

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lab report pam

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