142302 PRINCIPLES OF COMMUNICATION (POC) ANNA UNIVERSITY QUESTION PAPER NOVEMBER/DECEMBER 2011 for IT 3rd Semester ...
Posted by R.Anirudhan
B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2011.
B.Tech. – Information Technology
142302 — PRINCIPLES OF COMMUNICATION
Time : Three hours Maximum : 100 marks
Answer ALL questions.
PART A — (10 ´ 2 = 20 marks)1. What is the necessity of Modulation.
2. Differentiate between AM and FM, What is your choice for radio broadcast?
Justify your answer.
3. Define Probability of Error.
4. Compare: coherent and non-coherent communications.
5. Define quantization noise.
6. State sampling theorem.
7. What is PN Sequence?
8. What do you mean by Source Coding?
9. List the advantage and limitations of fibre Optical Communication.
10. Give uplink and downlink frequencies in satellite communication.
PART B — (5 ´ 16 = 80 marks)
11. (a) (i) Derive AM Modulated signal with relevant waveforms and
notations and draw the frequency spectrum of AM and explain. (10)
(ii) Explain AM Voltage and Power Distributions. (6)
(b) (i) Discuss on frequency analysis of angle modulated waves. (8)
(ii) Describe the bandwidth requirements for angle modulated wave. (8)
12. (a) (i) Define FSK and give the symbols of BFSK and explain the
modulation mechanism with relevant waveforms and expressions.
(ii) Draw FSK transmitter and receiver block diagrams and explain the
functions of each block. (8)
(b) (i) Explain the QPSK system with appropriate expressions and
(ii) Draw QPSK transmitter and receiver block diagrams and describe
the functions of each block. (8)
13. (a) Explain the modulation and demodulation process of PCM in detail.
Discuss on companding. (16)
(b) (i) Compare PCM with DM (3)
(ii) Discuss on the Principle and Process of delta modulation with
necessary sketches and formulae. (8)
(iii) What are the limitations of delta modulation and how will you
overcome them in adaptive delta modulation? (5)
14. (a) Explain the principle and operation of direct sequence spread spectrum
system in detail with an appropriate example. (16)
(b) (i) Explain and compare FDMA, TDMA and CDMA (8)
(ii) Explain the advantages and limitations of a CDMA based wireless
communication system. (8)
15. (a) Explain the principles and operation of LEO, MEO and GEO satellites.
(b) Describe the following with reference to Fibre Optical communication
(i) Sources. (4)
(ii) Detectors. (4)
(iii) Fibre types. (4)
(iv) Losses encountered in optical communication systems. (4)