Question paper of Pre-University Examination of Analog Communication held at Guru Nanak Education Trust Group of Institution, Roorkee in EVEN Semester Session: 2012-13

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GURU NANAK EDUCATION TRUST GROUP OF INSTITUTION
ANALOG COMMUNICATION (TEC-405)
PRE-UNIVERSITY EXAMINATION
Session: 2012-13 / EVEN SEMESTER
B.Tech (ECE) 2nd
Year
Write down your Roll No on the Question paper. M.M. 100
Attempt All Questions. Each Questions carry equal Marks. Time: 2.30 Hr
1. Attempt any four questions
a. Explain frequency division multiplexing and time
division multiplexing, also compare them.
b. Compare the following amplitude modulated system
for transmission reception efficiencies
i. DSB-SC
ii. SSB-SC
c. Explain the following
i. Modulation index
ii. Envelope detector
iii. Baseband and pass band signals
iv. Signal power
d. What is meant by the term channel as applied to a
communication system.
e. Why is a high frequency carrier needed in a
communication system?
f. Explain the difference between analog and digital
communications.
2. Attempt any four questions
a. What is angle modulation? Explain different types of
angel modulation with mathematical expression.
b. Explain the relationship between phase modulation
and frequency modulation.
c. Draw the circuit diagram of varactor diode modulation
and explain its working.
d. Explain Armstrong method for generation of wideband
FM.
e. Write comparison between narrow band FM and wide
band FM.
f. Explain the working of balanced frequency
discrimination with the help of circuit diagram.
3. Attempt any four questions
a. What is Nyquist rate and Nyquist interval?
b. What are the merits of frequency modulation? Show
how a varactor can be used to produce a FM signal.
c. What is phase modulation? How is it related to
frequency modulation? Find the expression of FM
wave.
d. What are the fundamental limitations of
communication systems?
e. Explain single tone amplitude modulation with
mathematical expression.
f. Illustrate the principle of Armstrong system of
generating PM signal.
4. Attempt any two questions
a. What are the advantages of pulse modulation over
carrier wave modulation? Explain pulse amplitude
modulation and pulse time modulation with the help
of suitable waveforms.
b. State and prove the sampling theorem and also explain
natural sampling and flat top sampling with the help of
suitable diagram?
c. Explain the pulse code modulation system with its
respective block diagram and derive the relationship
for transmission bandwidth in a PCM system?
5. Define any two of the following
a. What are different types of noise associated with
communication system explain each in detail?
b. Explain noise sources and derive the expression for
voltage and current models of a noisy resistor?
c. Define any two
i. Equivalent noise bandwidth in communication
system
ii. Signal to noise ratio
iii. Noise figure
Roll No. +