Download DU (University of Delhi) B-Tech 7th Semester 1532 A CS703 Principles of Communication Engineering Question Paper

Download DU (University of Delhi) B-Tech (Bachelor of Technology) 7th Semester 1532 A CS703 Principles of Communication Engineering Question Paper

V This question pape: contains 4+1 printed pages]
Roll No; ' .
.S.No.onuestion Papgr : l532-A
-Un'iquePape-rCode ? ' /: 2343703 _ f v ? F77 ?
Name o'fthe. Phaper : C8703 Principles of Communication Epgin?eriflg'
Nam? ofth? Course; 1: B.Tech. i1; Co?puter Science ?Ailie?d Course
"Semester b :VII
Duration:3Ho?r?s ? h P- ' , I . ~ rMaximum Marksz75
Write your! ?RvoII'No. on the tfon immediately On receipt? of this qu?sgion paper.) '
There are two, parts of the .qu'cstg?n paperPart VI and Part II.
Part I'hasr Q?e-quespio? Which is c6?1pu?lspry. I
Prong Part1] Attempt any fbur out of six .que's?tidns.
? PaPt I ?7
QUESfiPH'NoLdiiwdhi?umo?z?i :
.1.v.-"(a).F?lmth?:h1a&s .519 ,.. ? , ., 15x1
(1') - Elemems of communication?system?are ................ ~. ..... .
-. ?l - '(ii) ?AM'athema?ca?y in?tl'ie time dox?ai? ?d?eq?ncygdomiain Sin Wave signal are I
? represented as ?
P.T.'O. .

(iii) . Steps involves in conversion ofanalog signal to digital signal are .
(iv) Carrier reedvery circuit is needed at thegrecbv'ery produce a coherent local carrier
called ............................ effect.
(v)_ Delay distortion isinot-importantin? ......................... but important
? Bin ...... f7,,.t.$L .7
(vi): ?Fo'r communication most important signals is/are (Analog or Digital or '
' Both)_ ...... .
(iiii) Inbut function x(t) is said to be transmitted without distortion if the output
(viii)
(ix),
, (x)
' (xi)
(xii)
signal y(r)? is defined as...._ ........ ....... .
Let the bandwidth Of signal is B, sampling. rate needed for the same.
is ..... 1'. .................. .
We need to eompute noise i'sidb; what will be the formula ....... ~ ..................... .
? Envelope is theongmal lsigqal; shothggaphically in pictorial form ......... , ........... .
In communication system the noise analysis is based on anideztlized form of noise
is called .................. ...... noise. .7 , ; , __'- _ .
In AmplitL-id?-i Moduiation (AM), iet the carrier veltage ahd .modul?ating
voltage are Vc and Vm, respectively; be represented by ......
and ............................ .
i 4._?__..,M__Cl;h ?

(b) -
. (c)
(d)
(e)
(xiii)
I (xiv;
(XV)
(i)
? (ii)
? (I)
(if)
(0
(i1)
('1)
t (it)
( 3 ), ' 15321A
In the standard method of evaluating the modulation index when calculating from
a
. a waveform such as my be seen on an oscilloscope, i.e. when both carrier and
the modulating voltages are known?. equati?ott for the same is .................... .
Mathematical representation (PM) of unmodulated carrier signal is expressed
A triinsmission 0f lilieiis said to-be lossless if R "= G ?= ........................ .
Explain the need of modulation iii communication system. ?' 2
Discuss the type. causes and effects of the various form of hoise which may be
1 Created within a receiverrcir an ampii?e?r, . ' 'i , e n ' 3 .
Draw hlock diagram 9f Amplitude Shift Keying and explain in brief. ? 2
7 Explain_Baila11cedModul?tonexpktm it?s working. ' ~ ' 73'
.7 Explain Doubling 8th Matching iri brief. ' K. 2
The characteristic for Impedance 20 = R0 +,jX0, write expression for General,
' Lossless and Distortionless cases. ' , ' '3
' Power spectrum density of signal voltage is,100 volts'and "of noise is 10 volts, ?
compute the noise ?gure for receiver in terms of dB. " v i 3
Explainiany two high ?equency transmission lines. ' 2
P.T.O.

(a)
(123?
(a) .
? , (4) 1532-A
Part [I
Atter?p?t any four questions from this part. All questions carry edual marks.
Draw block diagram of a communicatioh system, mention the elements of ascomvmunicati?on?
- system and describe their ?mctionality, V ? I" 5 ?_
What doyou understand by nen?linear distortions"? Explain it mathematically as well
- f
as with the diagram which shows the non-linearity: ? , , 5 '
Explain ainpiitude modulation, theote'tically as Well as mathematically and de?ne modulation
.?indeXofAMwav?, I ,7 . ,7 . s 5
-(b) '
(a)
Explain uahsmissioh line parameters, equation, with equivalenteircuitmodel of a di?eiential ,
length Delta (2) of two:conductor transmissibn line. ' ' 5
An. audio sighal? given as 415 sin 213(?15000? amplitude modulates a' carrier given as
?60 sin21t(100000t)? determine the follo'wing : t , . 5
Note '7. You'My assume signals for (i,ii & iii);- use izbove signals for (iv and v).
1
('1) - Sketch the atidio signal.
? (ii). ' Sketch the carrier signal,
' (iii) f Constructthe mo'dulated sign?aL. ~
' (iv) Determine the'modulation index and ?ercent modhla?oh. -
(v)_ What is the frequency of the audio signal and the carrier ?

)4 arm .L run-
(b)-
5 (a)
m
6 (a)
?- (b)
7] (a)
\
(1;)
1532-A?
( 5 ) ? . 1532-A
A bandwidth of 20 MHz 15 to be considered for the transmission of AM signals. If the
highest audio frequencies used to modulate the carriers and not to exceed 3 kHz how
' . may stations "could broadcast within thisband simultaneously without interfering with one
v
another ? . _ V i e ' 5
' Explain Frequency Modulation ma?iem?atically and de?ne?the advantages and disadvantages ?
of Frequency Modulation over Amplitude Modulation. . A ?5?
Explain the. concept of Angular Modulation mathematically with instantaneous angular
velocity, define __ the relationship between Phase. Modulation (PM) and, Freqtiency
' Consider a transmissiOn line of length L, explain mathematical expression to cOmput'e
impedance, standingwavji?ratio (SWR) and Power ? A \ 5
What are the di?erent?transmission line chats? Explain smith chart in detail: 5
, Explain mathematically the noise in AM ahdAnglegModulatioVn system. What are the
effects in small noise and large noise ?, ~ A ? ? 5
Wlmaremecncmtelement?UseofuansrmssnonhneascuemtelemamWhyVConvemOMl
? circuit element do not behave as expected at high frequency. 7. ? .5
' .5? V V I 1-00
"w?V? ?