North Maharashtra University 2011 B.E Computer Science and Engineering .s.ecomputer -university question paper

Monday, 04 February 2013 04:15Web

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THIS IS THE ques. PAPER OF "DATA COMMUNICATION" OF second YEAR OF COMPUTER ENGINEERING.

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Scut No. j xj / T7 1 <3 & ]

DATA COMMUNICATIONS (New)

P Page* ; 3

Tim. 3 Hour, M.< VU*:IOO

Imtrmctums - / J Attempt any mbijuruiuns from each Unit

2) Draw meat diagrams if ntcnsary i; Asmme tuitnbt* data if rtquirtd

UNIT-I

1. a) i) What are the direction of (Tom in I Him Communication ? Also rtate the

characteristics of Data Communication Sy#urm 5

) p) How long time does an electromagnetic wave take to travel a signAi to reach upto Moon, the approximate distance up to moon it 240,000 miles and velocity of signal in pocc b I H6.000 mi 'see ? 2

q) How long lime does the Radio ugnal take to travel a distJMK* of 3000 miles in space, the velocity of the signal m spec* ti I *0,000tm>ec ? Also calculate the time if the signal is sent through cable with ptopaganon speed of 75% of that of the velocity of the signal in sptct. J

b) t) Compare with neat diagram Network Hardware and Network Software J

) A system has 10 watts o( signal power, I wau of noise powvr and the hundwidth of I kl 1/ what should be the channel upicit) ?

fi\ * kxplua in detail variou* data rate limits of transmmion impairment*.

) The power of signal U 100 mw and the power of noise U 1 mw. What are the values of SNR and SNRd_fi ?

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UNIT 11

a) i) What is Modulation ? Ixpttiin with neni diagram* AM am* f M-

) A nrtivk with Bandwidth of J 0 Mbps can past only an average of 12,000 fhunes per minute* with cach frame carrying an average of¹0.000 bttt. What ii the throughput of the network in Mbpt ?

h) 0 A Telephone Line has bandwidth of 3000 ft*. the slgnaJ-to-noise b 3162. what it the channel capacity 7

iO State the various u;hmts used lor Htrv*r> to Digital encoding Explain with nc*i waveform 2HIQ and Mi T-3 codings. Abo explain block coding

8

scheme

c) <j) Explain with neat diagram ASK, I SK and PSK ? AUo explain wfcat is

QAM 7 5

i) ExpJuin the role of MODEM

m) The noiseless channel with bandwidth ol >000 H*. trwumittirtg * *9** **> two signal levels, what is the maximum bitrate ?

1/NIT - III

J b) 0 What multiplexing ? What arc tha factors on wheh the rf*ce of mutaptaung

depend* n What are the types of multiplexing ** Explain FOM m detail fc

) What is the role of telephone network ? Explain with neat diagram the tnajor components of Telephone System 4

b) ) What a the switching 0 Why it b essentia)' Whdtthe types of switching ' Explain m detail message switching. fc

i) fcjtplain the concepts of LATAs and making connections m telephone sywttm- 4

c) i) What is Transrrussiofi media ' Whal are the various characteristics of

iranamiwion media ? What art the ty pes of transmission mcdit ? Explain Kadncrwave, Microwave and infrared it) frxpUin Analog and Digital services in Telephone Network*. 1

UNIT IV

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4. a) i) txpUiin in detail VRC and LRC. if) Fxplain stop-and*wait protocol b) i) Fxplain Selective-Repeat Protocol.

i) Explain the concept of 7 bit Hamming Code with an example

C) J) hxplain the concept of C'RC ? Give an example of CRC checksum for message polynomial.

Gix) * x* x² and Generator polynomial P(x) x* + x² + I iif Explain GO-BA(K - N protocol.

UNIT - V

5 a) Write short note* :

i> SDI'C/HDLC

ii) Fast Ethernet

g) CSMA/CO. 10 Write short note* : i> X.21 and X.25

a> ( I>MA