Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Summer 5th Sem New 2151004 Electronic And Communication Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? SUMMER 2019
Subject Code: 2151004 Date: 17/06/2019
Subject Name: Electronic and Communication
Time: 02:30 PM TO 05:00 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) Explain how bandwidth of a signal (information) affects its transmission. 03
(b) Explain need of modulation. 04
(c) Explain Automatic Gain Control (AGC) and discuss difference between
AGC and Delayed AGC.
07
Q.2 (a) What is the difference between SSB and VSB wave? 03
(b) Compare : Frequency modulation and Amplitude Modulation 04
(c) The frequency span to be received by a receiver is from 525KHz to
1650KHz. If Cmin of tuning circuit is limited to 50pF by a trimmer of
25pF, calculate the value of padder capacitor, if the maximum value of
variable capacitor is 450pF. The If is 465KHz.
07
OR
(c) A FM voltage is represented by e FM=12sin(6 x 10^8t + 5cos 1250t) Find
Carrier Frequency, Modulating Frequency, Modulation Index, Maximum
Deviation, Power dissipation across 10?.
07
Q.3 (a) Two resistors 10 K? and 25 K? are at room temperature (300K) for a
bandwidth of 150KHz. Calculate thermal noise, if two resistors are in
series and if two resistors are in parallel.
03
(b) Explain the interferences in angle modulated systems. 04
(c) Explain basic principal of dual slope detector type FM demodulators. 07
OR
Q.3 (a) Define : 1) Signal to noise ratio 2) Image Frequency Rejection Ratio
3) Phase modulation
03
(b) An amplifier with 10dB noise figure and 4dB power gain is cascaded with
a second amplifier which has a 10dB power gain. What is the overall noise
figure?
04
(c) Explain the Armstrong method of Frequency modulated signal generation. 07
Q.4 (a) For superheterodyne receiver, Define : Sensitivity , Selectivity and Image
frequency
03
(b) Explain reason and remedy for Diagonal clipping and Negative peak
clipping.
04
(c) What is bandwidth efficient AM? Explain Phase shift method to generate a
bandwidth efficient AM signals.
07
OR
Q.4 (a) Describe the problems in TRF receiver. 03
(b) Explain the working of superheterodyne receiver with help of block
diagram.
04
(c) Derive the mathematical expression of Amplitude Modulated signal and
identify the spectrum of AM wave.
07
FirstRanker.com - FirstRanker's Choice
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? SUMMER 2019
Subject Code: 2151004 Date: 17/06/2019
Subject Name: Electronic and Communication
Time: 02:30 PM TO 05:00 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) Explain how bandwidth of a signal (information) affects its transmission. 03
(b) Explain need of modulation. 04
(c) Explain Automatic Gain Control (AGC) and discuss difference between
AGC and Delayed AGC.
07
Q.2 (a) What is the difference between SSB and VSB wave? 03
(b) Compare : Frequency modulation and Amplitude Modulation 04
(c) The frequency span to be received by a receiver is from 525KHz to
1650KHz. If Cmin of tuning circuit is limited to 50pF by a trimmer of
25pF, calculate the value of padder capacitor, if the maximum value of
variable capacitor is 450pF. The If is 465KHz.
07
OR
(c) A FM voltage is represented by e FM=12sin(6 x 10^8t + 5cos 1250t) Find
Carrier Frequency, Modulating Frequency, Modulation Index, Maximum
Deviation, Power dissipation across 10?.
07
Q.3 (a) Two resistors 10 K? and 25 K? are at room temperature (300K) for a
bandwidth of 150KHz. Calculate thermal noise, if two resistors are in
series and if two resistors are in parallel.
03
(b) Explain the interferences in angle modulated systems. 04
(c) Explain basic principal of dual slope detector type FM demodulators. 07
OR
Q.3 (a) Define : 1) Signal to noise ratio 2) Image Frequency Rejection Ratio
3) Phase modulation
03
(b) An amplifier with 10dB noise figure and 4dB power gain is cascaded with
a second amplifier which has a 10dB power gain. What is the overall noise
figure?
04
(c) Explain the Armstrong method of Frequency modulated signal generation. 07
Q.4 (a) For superheterodyne receiver, Define : Sensitivity , Selectivity and Image
frequency
03
(b) Explain reason and remedy for Diagonal clipping and Negative peak
clipping.
04
(c) What is bandwidth efficient AM? Explain Phase shift method to generate a
bandwidth efficient AM signals.
07
OR
Q.4 (a) Describe the problems in TRF receiver. 03
(b) Explain the working of superheterodyne receiver with help of block
diagram.
04
(c) Derive the mathematical expression of Amplitude Modulated signal and
identify the spectrum of AM wave.
07
2
Q.5 (a) Define : signal energy and signal power 03
(b) Explain technology used in amateur radio. 04
(c) Derive equation for resonant frequency and Q factor for parallel tuned
circuit.
07
OR
Q.5 (a) Explain Skin effect. 03
(b) Explain the importance of HAM radio during natural calamities. 04
(c) State and prove time scaling property of Fourier transform. Explain the
effect of time scaling on bandwidth of the signal.
07
*************
FirstRanker.com - FirstRanker's Choice
This post was last modified on 20 February 2020