Anna University Chennai EC2252 - COMMUNICATION THEORY 4th Semester BE ECE April May 2015 Latest Question Paper Collection:
Anna University Chennai
B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2015.
Fourth Semester
Electronics and Communication Engineering
EC2252 - COMMUNICATION THEORY
(Regulation 2008)
Subject Code : EC2252
Department : Electronics and Communication Engineering
Year/Semester : 2nd/4th semester
Regulation : 2008
PART-A
1. A carrier is amplitude modulated to a depth of 80%. Calculate the total power in the modulated wave, if the carrier is 10 watt.2. Draw the frequency spectrum of VSB. Where it is used?
3. State the Carson’s rule.
4. Compare Narrowband and wideband FM.
5. Define noise figure.
6. Define SNR.
7. What are the methods to improve FM threshold reduction?
8. What is capture effect?
9. Define entropy and its properties.
10. What is the channel capacity of a BSC and BEC?
PART-B
11. (a) Draw the block diagram of superhetrodyne receiver and explain the functions of each block.Or
(b) (i) Discuss the methods of demodulation of DSBFC, DSBSC, SSBFC, SSBSC schemes.
12. (a) (i) Explain the principle of indirect method of generating a wideband FM signal.
(ii) Discuss the effects of non linearities in FM systems.
(b) (i) Draw the circuit diagram of Foter-Seeley discriminator and explain its working.
(ii) What are the applications of PLL?
13. (a) Write short notes on Shot noise, Thermal noise, White noise.
Or
(b) Write the details about narrow band noise and the properties of quadrature components of narrow band noise.
14. (a) Obtain the expression for figure of merit of DSB-SC receiver using coherent detection.
Or
(b) Explain pre-emphasis and de-emphasis in detail.
15. (a) (i) Find the Huffman coding for the probabilities P={0.0625, 0.25, 0.125, 0.125, 0.25, 0.125, 0.0625} and the efficiency of the code.
(ii) Discuss the source coding theorem.
Or
(b) (i) State and explain Shannon’s theorem on channel capacity.
(ii) Differentiate lossless and lossy coding
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