Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 5th Sem New 2151004 Electronic And Communication Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? WINTER 2018
Subject Code:2151004 Date:07/12/2018
Subject Name:Electronic and Communication
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Define Following Terms:
1.Phase Modulation 2.Modulation Index 3.Image Frequency
03
(b) State and prove the following properties of Fourier transform.
(1) Time shifting (2) Frequency shifting
04
(c) Define communication. Draw The basic block diagram of communication
system explain the function of each block.
07
Q.2 (a) What is modulation and list out the need of modulation. 03
(b) State Parseval?s theorem. 04
(c) Draw and explain parallel tuned circuits in detail. Also derived equation for
Resonance frequency and Q-factor for the parallel tuned circuits.
07
OR
(c) Write a short note on self-capacitance of a coil. 07
Q.3 (a) State and prove Time-scaling property of Fourier transform. 03
(b) An AM signal is represented by e(t) = (10+ 4 cos 800 ? t) cos (2 ? ?10
5
t)
Find: Modulation index, and transmission Bandwidth required for this AM
signal.
04
(c) Explain Amplitude Modulation with required waveforms. Also give
mathematical representation of Amplitude modulated Wave.
07
OR
Q.3 (a) State and prove Duality property of Fourier transform. 03
(b) Two resistors 15 k? and 30 k? are at room temperature (290K) for a
bandwidth of 300 kHz. Calculate thermal noise for each resistor, if two
resistors are in series.
04
(c) Explain Phasing method for generation a SSBSC signal in detail. 07
Q.4 (a)
Give Comparison between FM and AM system.
03
(b)
With related to Amplitude modulation discuss following parameters: (I)
Bandwidth requirement (II) Power distribution in sidebands and carrier.
04
(c) Describe briefly shot noise, partition noise and flicker noise with all details. 07
OR
Q.4 (a)
Discuss drawbacks of direct method for FM generation.
03
(b) Draw the circuit diagram of delayed AGC. What are the advantages of
delayed AGC?
04
(c) Derive Friis formula for noise factor of cascaded amplifier. 07
Q.5 (a)
Explain what double spotting is and how it arises.
03
(b) Explain pre-emphasis and de-emphasis in relation to FM. 04
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? WINTER 2018
Subject Code:2151004 Date:07/12/2018
Subject Name:Electronic and Communication
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
MARKS
Q.1 (a) Define Following Terms:
1.Phase Modulation 2.Modulation Index 3.Image Frequency
03
(b) State and prove the following properties of Fourier transform.
(1) Time shifting (2) Frequency shifting
04
(c) Define communication. Draw The basic block diagram of communication
system explain the function of each block.
07
Q.2 (a) What is modulation and list out the need of modulation. 03
(b) State Parseval?s theorem. 04
(c) Draw and explain parallel tuned circuits in detail. Also derived equation for
Resonance frequency and Q-factor for the parallel tuned circuits.
07
OR
(c) Write a short note on self-capacitance of a coil. 07
Q.3 (a) State and prove Time-scaling property of Fourier transform. 03
(b) An AM signal is represented by e(t) = (10+ 4 cos 800 ? t) cos (2 ? ?10
5
t)
Find: Modulation index, and transmission Bandwidth required for this AM
signal.
04
(c) Explain Amplitude Modulation with required waveforms. Also give
mathematical representation of Amplitude modulated Wave.
07
OR
Q.3 (a) State and prove Duality property of Fourier transform. 03
(b) Two resistors 15 k? and 30 k? are at room temperature (290K) for a
bandwidth of 300 kHz. Calculate thermal noise for each resistor, if two
resistors are in series.
04
(c) Explain Phasing method for generation a SSBSC signal in detail. 07
Q.4 (a)
Give Comparison between FM and AM system.
03
(b)
With related to Amplitude modulation discuss following parameters: (I)
Bandwidth requirement (II) Power distribution in sidebands and carrier.
04
(c) Describe briefly shot noise, partition noise and flicker noise with all details. 07
OR
Q.4 (a)
Discuss drawbacks of direct method for FM generation.
03
(b) Draw the circuit diagram of delayed AGC. What are the advantages of
delayed AGC?
04
(c) Derive Friis formula for noise factor of cascaded amplifier. 07
Q.5 (a)
Explain what double spotting is and how it arises.
03
(b) Explain pre-emphasis and de-emphasis in relation to FM. 04
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2
(c) What tracking means in a superhetrodyne receiver? Explain three points
tracking in radio receiver.
07
OR
Q.5 (a)
Define the following terms related with radio receivers: (1) Selectivity (2) Fidelity
(3) sensitivity
03
(b) Explain Phased Look Loop with all necessary details. 04
(c) Draw the block diagram of Tuned Radio Frequency (TRF) Receiver and
explain its operation. Describe the problems in TRF receiver.
07
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This post was last modified on 20 February 2020