Download GTU BE/B.Tech 2019 Winter 6th Sem New 2163206 Analog And Digital Communication Ict Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER- VI (New) EXAMINATION - WINTER 2019

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Instructions:

1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

MARKS

Q.1

1. Explain General Communication System with Block Diagram. (03)

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2. Derive Mathematical Representation of Amplitude Modulation and Explain Signification of Modulation Index with necessary Waveforms. (04)
3. Write a Short note on Super Heterodyne Receiver. (07)

Q.2

1. Explain CDMA in brief. (03)
2. State Friss Formula for overall Noise Factor of amplifiers in cascade 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 (04)

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3. What are the different methods for Generation of FM Signals? Explain any one method in detail. (07)

OR

1. Explain the importance of Pre-emphasis-and De-emphasis circuits in FM. Sketch a typical Pre-emphasis and De-emphasis circuit. (07)

Q.3

1. Write a short note on Full carriers’ AM transmitters (03)

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2. An Amplifier operating over the Frequency Range from 19 MHz to 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 (04)
3. Draw Block diagram of frequency hopping spread spectrum (FHSS) system and Explain Frequency Hopping with necessary waveforms. (07)

OR

1. Write short note on latest trends in Digital Communication (03)
2. Give comparison of Wideband and Narrowband FM. (04)

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3. An AM modulating signal 5*Sin (2p x 200t) is used to modulate a 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. (07)

Q.4

1. Write a short note on Radio Communication with neat Sketch. (03)
2. Derive the formula for the instantaneous value of an FM voltage and define the modulation index. And draw the waveforms of information signal and its FM modulated signal. (04)
3. Enlist and compare different digital modulation techniques. (07)

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OR

1. A FM system, maximum deviation is 75 KHz Calculate bandwidth of system using Carson’s Rule. (07)
2. Introduce pulse width modulation. With neat sketch explain generation of PWM. (04)
3. Explain working principle of Delta modulation with help of block diagram. What are the problems associated with Delta Modulation? (07)

Q.5

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1. What do you mean by VSB Modulation and Why it is used? (03)
2. For Binary data: 1101001100111001 Draw ASK, FSK and PSK waveform. (04)
3. Compare Amplitude Modulation, Frequency Modulation and Phase Modulation. (07)

OR

1. State the Advantages and Application of Spread Spectrum Communication. (03)

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2. Explain Pulse Code Modulation with necessary waveforms. (04)
3. What is the difference between Coherent and Non-Coherent Detection techniques? Discuss Coherent Detection of FSK signal. (07)

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