Satellite Communication & networks - Dec 2013

Electronics & Telecomm. (Semester 8)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) What is spot beam ? Explain its use in satellite communication.(5 marks) 1 (b) Define
(i) Argument of Perigee.
(ii) Right Ascension of ascending node(5 marks) 1 (c) Compare ELV and STS methods of launching satellite.(5 marks) 1 (d) Explain rain depolarisation in detail.(5 marks) 2 (a) What are look angles ? Explain its significance in relation to satellite position. Hence solve an Earth station is located at a latitude of 12° south and longitude of 52°W. Calculate antenna look angles for 0 satellite at 70°W.(10 marks) 2 (b) Describe various reasons for perturbation of satellite orbits(10 marks) 3 (a) Which type of double reflectors are used in satellite communication. Explain in detail.(10 marks) 3 (b) What is intermodulation noise ? Does it affect the C/N ratio. Derive the expression for same(10 marks) 4 (a) What is TT&e subsystem ? Explain the type of antennas used for tracking and command signal transmitting during transfer orbit.(10 marks) 4 (b) Draw and explain block diagram of FDM/F M/FDMA earth station(10 marks) 5 (a) Compare advantages of TDMA, FDMA and DS-SS CDMA Satellite signal.(10 marks) 5 (b) Explain satellite space and mass power estimate in detail.(10 marks) 6 (a) What is eclipse ? Are there any ways of avoiding eclipse during lifetime of satellite.(10 marks) 6 (b) Explain the following :-
(i) Point of compression of MB.
(ii) AM to PM conversion.
(iii) UP and output back off ratio(10 marks)

Write short notes on (any two)

7 (a) TDMA synchronization(10 marks) 7 (b) Orbital parameters(10 marks) 7 (c) Lifetime of satellite(10 marks)