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JulyAugust 2021

This document outlines the examination structure for the B.Tech II Year II Semester in Analog and Digital Communications at Jawaharlal Nehru Technological University Hyderabad. It includes eight questions covering topics such as COSTAS loop, amplitude modulation, FM signal derivation, noise performance, superhetrodyne receivers, PCM systems, PWM signal generation, and FSK detection. Students are required to answer any five questions, with all questions carrying equal marks.

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26 views1 page

JulyAugust 2021

This document outlines the examination structure for the B.Tech II Year II Semester in Analog and Digital Communications at Jawaharlal Nehru Technological University Hyderabad. It includes eight questions covering topics such as COSTAS loop, amplitude modulation, FM signal derivation, noise performance, superhetrodyne receivers, PCM systems, PWM signal generation, and FSK detection. Students are required to answer any five questions, with all questions carrying equal marks.

Uploaded by

sohelpasha25
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Code No: 154AC R18

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD


B.Tech II Year II Semester Examinations, July/August - 2021
ANALOG AND DIGITAL COMMUNICATIONS
JN
(Electronics and Communication Engineering)
Time: 3 Hours Max. Marks: 75
Answer any five questions
TU
All questions carry equal marks
---

1.a) Explain about COSTAS loop with a neat block diagram for demodulating DSB-SC
wave.
H
b) Explain the working of envelope detector with a neat circuit diagram. [8+7]

2.a) Define a standard form of amplitude modulation and explain the time and frequency
U
domain expression of an AM wave.
b) Calculate the percentage power saving when the carrier and one of the sidebands are
se
suppressed in an AM wave modulated to a depth of 100% and 50%. [7+8]

3.a) Derive the expression for FM signal from fundamentals and differentiate narrow
d
band FM and wide band FM.
b) For an FM modulator with a modulating signal m(t)= Vmsin(300×103t), the carrier
Signal VC(t)=8 sin(6.5×106t) and the modulator index = 2. Find out the significant
27
sideband frequencies and their amplitudes. [7+8]

4.a) Compare noise performance of PM and FM system.


-0
b) Explain the indirect method of generation of FM wave and any one method of
demodulating an FM wave [6+9]
7-
5.a) Draw the block diagram of Superhetrodyne receiver and explain the function of each
block.
b) Compare and contrast AM and FM receivers. [9+6]
21
6.a) With a neat diagram explain AM receiver tracking and tracking curve.
b) How the performance of the PCM system is influenced by the noise and calculate SNR in
the PCM system? [7+8]
AM
7.a) With a neat block diagram explain the generation of PWM signal.
b) With a neat waveform explain Flat-top PAM sampling. [7+8]

8.a) Discuss about the coherent FSK detector and non-coherent FSK detector.
b) Explain the generation and reception of DPSK signals with a neat block diagram. [7+8]

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