A G1011 Pages: 2

Reg No.:_ Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(S), MAY 2019

Course Code: EE401
Course Name: Electronic Communication

Max. Marks: 100 Duration: 3 Hours
PARTA
Answer all questions, each carries 5 marks. Marks
1 With the help of block diagram, explain the working of balanced modulator. (5)
2 Draw the block diagram of super heterodyne receiver and explain the function of (5)

mixer stage.

3 Explain the block diagram of a colour television transmitter (5)

4 Differentiate between PPM and PWM with sketches. (5)

5 Explain the significance of TDMA for satellite communication? (5)

6 Explain the role of earth station in the satellite communication systems? (5)

7 With a block schematic explain the operation of GPS. (5)

8 Explain how cell splitting improves the capacity. (5)
PART ‏تا‎

Answer any two full questions, each carries 10 marks.

9 a) A modulating signal vm(t)= 5 sin (6280 t) is used to modulate a carrier signal (5)
vc(t)= 15 sin(62800 0 . Determine the modulation index, side band frequencies,
amplitudes and bandwidth. Also draw the frequency spectrum.

b) When do you prefer VSB signals to SSB. Why? (5)

10 a) With a neat schematic explain the function of each block in FM transmitter using (6)
Armstrong Modulator.

b) Explain following parameters of Radio receiver: i) adjacent channel selectivity (4)
and ii) image frequency rejection.

11 a) Draw typical AGC circuit for a super heterodyne receiver and explain its (5)
working.

b) Explain the working principle of a FET reactance modulator for FM generation. (5)
PART C
Answer any two full questions, each carries 10 marks.
12 a) Derive the basic radar equation, as governed by the minimum receivable echo (5)

power Pmin.

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