GUJARAT TECHNOLOGICAL UNIVERSITY
SEMESTER-VI(NEW) — EXAMINATION - SUMMER 2019
--- Content provided by FirstRanker.com ---
Subject Code:2163206 Date:16/05/2019
Subject Name:Analog and Digital Communication (ICT)
Time:10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
- Attempt all questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
--- Content provided by FirstRanker.com ---
MARKS
Q.1 (a) Explain General Communication System with Block Diagram. 03
(b) Derive Mathematical Representation of Amplitude Modulation and 04 Explain Signification of Modulation Index with necessary Waveforms.
--- Content provided by FirstRanker.com ---
(c) Write a Short note on Super Heterodyne Receiver. 07
Q.2 (a) Explain CDMA in brief. 03
(b) An Amplifier operating over the Frequency Range from 19 MHz to 04 22 MHz has a 5 KQ input resistor. Using thermal agitation noise formula, find RMS Noise Voltage and Noise Power at the input to this amplifier if the ambient temperature is 29°C. Boltzmann’s Constant k=1.38 x 10" J/K.
(c) What are the different methods for Generation of FM Signals? 07 Explain any one method in detail.
OR
--- Content provided by FirstRanker.com ---
(c) Explain the importance of Pre-emphasis and De-emphasis circuits in 07 FM. Sketch a typical Pre-emphasis and De-emphasis circuit.
Q.3 (a) Write a short note on Radio Communication with neat Sketch. 03
(b) State Friss Formula for overall'Noise Factor of amplifiers in cascade 04 and Using Friss Formula, Find Overall Noise Figure of three stage cascaded amplifier, each stage having a power gain of 10 dB and noise figure of 5 dB
(c) Draw Block diagram of frequency hopping spread spectrum (FHSS) 07 system and Explain Frequency Hopping with necessary waveforms.
OR
--- Content provided by FirstRanker.com ---
Q.3 (a) Give comparison of Wideband and Narrowband FM. 03
(b) Write a short note on Full carriers AM transmitters 04
(c) An AM modulating signal 5*Sin (2p x 200t) is used to modulate a 07 carrier signal 25*Sin (2p x 25000t). Find modulation index, percentage modulation, frequencies of sideband components and their amplitude. Draw the spectrum of AM wave.
Q.4 (a) Introduce pulse width modulation. With neat sketch explain 03 generation of PWM.
(b) Derive the formula for the instantaneous value of an FM voltage and 04 define the modulation index. And draw the waveforms of information signal and its FM modulated signal.
--- Content provided by FirstRanker.com ---
(c) Enlist and compare different digital modulation techniques. 07
Q.4 (a) For FM System, the modulating frequency is 10 KHz and maximum 03 deviation is 75 KHz Calculate bandwidth of system using Carson’s Rule.
(b) Write short note on latest trends in Digital Communication. 04
(c) Explain working principle of Delta modulation with help of block 07 diagram. What are the problems associated with Delta Modulation?
--- Content provided by FirstRanker.com ---
Q.5 (a) What do you mean by VSB Modulation and Why it is used? 03
(b) For Binary data: 1101001100111001 Draw ASK, FSK and PSK 04 waveform.
(c) Compare Amplitude Modulation, Frequency Modulation and Phase 07 Modulation.
OR
Q.5 (a) State the Advantages and Application of Spread Spectrum 03 Communication.
--- Content provided by FirstRanker.com ---
(b) Explain Pulse Code Modulation with necessary waveforms. 04
(c) What is the difference between Coherent and Non-Coherent 07 Detection techniques? Discuss Coherent Detection of FSK signal.
--- Content provided by FirstRanker.com ---
This download link is referred from the post: GTU BE 2019 Summer Question Papers || Gujarat Technological University