# DC by topraveesh

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```									BTS(C) - IV - 07-003 (A)
B. Tech Degree IV Semester (Special Supplementary)
Examination, March 2007
CS 403 DATA COMMUNICATION
Time: 3 Hours
Maximum Marks : 100
(a)
What is Modulation? Why modulation is needed in transmitting message?â¨Compare the features of frequency modulation and phase modulation.â¨Write notes on balanced modulator.
I.
(6)
(b)
(7)
(c)
(7)
OR
n.
(a)
In a FM system if the modulation index is doubled by halving the modulationâ¨frequency. What will be the effect of minimum deviation?
What are the principal features of AM & FM? Explain the frequency spectrum ofâ¨an AM wave.
(10)
(b)
(10)
(a)
m.
Explain a method of FM reception.
With suitable block diagram explain the working of FM stereo transmitter.
(10)
(b)
(10)
OR
(a)
Draw the schematic of an AM transmitter. Explain the function of each block in theâ¨above diagram.
How is the constant intermediate frequency achieved in the superheterodyne receiver?â¨Define the terms
IV.
(10)
(b)
(5)
(c)
(i) Fidelity
(ii) Image frequency
(5)
V,
(a)
What is meant by sampling, quantization and quantization error?
Describe Delta modulation system, What are die limitations of this system? How
these can be overcome?
(10)
(b)
(10)
OR
Explain the principle of operation of a QPSK Transmitter and Receiver.
VI.
(a)
(12)
Explain fully what is meant by FSK.
(b)
(8)
Quote the Shenon-Hartley theorem, defining each term in the formula. What is theâ¨fundamental importance of this theorem?
Write notes on digital PBXs.
vn.
(a)
(10)
(b)
(10)
OR
vm. (a)
Define transmission path and transmission rate.
What do you mean by channel capacity?
Differentiate between bit rate and band rate. What is the relation between the channelâ¨capacity bandwidth and signal power and noise power in a communication system?
(8)
(b)
(4)
(c)
(8)
Discuss four error detection methods.
(10)
IX. (a)
Explain the working of Goback - N ARQ.
(10)
(b)
OR
Explain how error detection is done with CRC Codes.â¨Explain how Hamming code is useful in error correction.
(10)
(a)
X.
(b)
(10)
*
*
-4
S* /
a

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