Mahatma Gandhi University (MGU) 2005 M.Sc Electronic Science Modern Communication System - Question Paper

M.Sc. (ELECTRONICS) DEGREE EXAMINATION, JANUARY 2005

First Semester

MODERN COMMUNICATION SYSTEM

Time : 3 Hours Maximum : 75 Marks

ans any 6 ques. from Part A.
ans any 3 ques. from Part B.
ans all ques. of Part C.

Part A

1. What is modulation? discuss the need of modulation.
2. Compare AM and FM.
3. What is Nyquist rate? discuss.
4. Explain quantization in PCM.
5. Describe a Public Switched Telephone Network.
6. What is trunk circuits, in telephony?
7. What is a geostationary orbit in satellite communication?
8. List the various multiple access methods in satellite communication.
9. Write short note on digital cellular radio.
(6 X two = 12 marks)

Part B

10. Explain a method of DSBSC-AM generation.
11. Draw neat diagram and discuss the working of PAM generator and detector.
12. Explain an electronic telephone exchange switching system.
13. Explain the roles of base station antenna and mobile antenna in mobile communication.
14. Brief on hybrid microwave system.
(3 X five = 15 marks)

Part C

15. (a) discuss 3 various ways of generating SSBSC-AM, using balanced modulator.
Or
(b) discuss indirect form of FM generation. define FM demodulation using discriminator.
16. (a) discuss the principle of Amplitude shift keying. With help of circuit diagram, discuss ASK generation.
Or
(b) discuss with diagram, generation and demodulation of PSK. elaborate the advantages of DPSK over PSK?
17. (a) With diagram, discuss a four-wire terminating set in telephony.
Or
(b) discuss how connection is made in telephony using step-by-step switching.
18. (a) discuss transmission path ‘d’ in satellite communication. Derive formula for ‘d’. What is the condition for minimum path?
Or
(b) discuss the multiple access methods TDMA and FDMA in mobile communication.
(4 X 12 = 48 marks)

Earning:   Approval pending.