M.Sc. DEGREE EXAMINATION, NOVEMBER 2017
Second Semester
Physics
Elective — COMMUNICATION ELECTRONICS
(CBCS 2014 onwards)
Time 3 Hours Maximum 75 Marks
Part A (10 x 2 20)
Answer all questions.
1. What is the advantage of FM over AM?
2. Define power gain of Antenna.
3. When does the minimum shift keying occur?
4. Compare PAM with PWM.
5. How is the distance from the point of transmission and
the target determined by employing a radar system?
6. Compare Reflex Klystron with Multicavity Klystron.
7. Explain the difference between a step-index fiber and a
graded-index fiber.
8. Explain how energy is lost at a sharp bend in a fiber.
9. What is telemetry?
10. Give the general principle of analog cellular systems.
Sub. Code
4MPH2E3
AFF-4868
2
WS4
Part B x 5 25)
Answer all questions, choosing either or
11. Derive the formula for instataneous value of an FM
voltage and define the modulation index.
Or
Write shortly about Hertzian dipole and half wave
dipole.
12. Derive the equation describing natural PAM signal
and explain the system configuration for the
generation of a five-channel time division
multiplexed PAM signal.
Or
Discuss about error control coding and establish the
relationship between average transmitted power
and bit rate.
13. Describe the principle, construction and operation of
Gunn diode with neat sketch.
Or
With the help of a block diagram explain the
working of pulse radar.
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15. A satellite communications link is setup between
earth stations at and
Determine the one-way propagation delay time for
the link.
Or
Discuss shortly about planning and operation of
cellular system.
Part C x 10 30)
Answer any three questions.
16. What is Phase Modulation Explain the equivalence
between PM and FM. Explain how FM may be obtained
from PM.
17. Explain frequency shift keying. How is FSK realized?
Explain with wave forms.
18. Explain shortly any two devices for the generation of
microwaves.
19. Draw the block diagram of optical fibre
communication systems and explain it.
What are the advantages of optical fibre
communication?
20. Describe the uplink and downlink power budget
calculations for communications with suitable examples.
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