Satellite Communication & networks - May 2014

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) Explain the significance of microwave frequencies in satellite communication(5 marks) 1 (b) State and explain Kepler's Laws(5 marks) 1 (c) What are advantages of satellite communication over terrestrial communication.(5 marks) 1 (d) What is transponder ? Explain single conversion transponder(5 marks) 1 (e) What is meant by polarization of Satellite signals. Explain ionospheric and rain depolarization.(5 marks) 2 (a) What is telemetry tracking and command subsystem ? Explain its functioning with block diagram.(10 marks) 2 (b) Draw block diagram of transmit-receive type earth station. Explain each block in brief.(10 marks) 3 (a) Explain spin stabilization and 3-axis stabilization methods. Mention their merits and demerits.(10 marks) 3 (b) What do you mean by system noise temperature ? How does it affect C/N and GT ration(10 marks) 4 (a) What do you understand by reliability and space qualification ? Explain significance of bath-tub curve.(10 marks) 4 (b) Explain different types of antenna used in satellite communication.(10 marks) 5 (a) A Geostationary satellite is located 35° ?W. What are its look angles and range from (i) Brad ford UK station (54°N, 2°W) (ii) Blacksburg USA (37°N. 80°W).(10 marks) 5 (b) What are different methods of launching of satellite ? Explain.(10 marks) 6 (a) Explain SPADE system of FDMA(10 marks) 6 (b) Explain with neat block diagram the FH-CDMA and DS-CDMA systems. Also list advantages ofCDMA system.(10 marks)

Write short note on (any two)

7 (a) Orbital Parameters(10 marks) 7 (b) VSAT(10 marks) 7 (c) Combined uplink and downlink C/N ratio.(10 marks)