B.TECH - Semester 8 satellite communication Question Paper 2019 (nov)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Define and explain subsatellite point.
- What are the factors which decide selection of launch vehicles?
- Explain attitude control of a satellite.
- List the steps used in the design of a satellite communication link.
- Why pre-emphasis and de-emphasis are needed in FM transmission?
- Draw the block diagram of a band-pass transmission system for digital data and explain the functions of the blocks.
- How is synchronization achieved in TDMA systems?
- Draw the block diagram of a typical VSAT earth station, and briefly explain it.
- Draw a simplified block diagram of a DBS-TV uplink earth station and explain it.
- A 12 GHz direct broadcast satellite link was found to experience 4 dB of rain attenuation at an elevation angle of $45^{\circ}$ for $0.01 \%$ of the time in an average year. What would be the rain attenuation measured at the same time percentage for ...
- (a) Derive expressions for,
- (i) elevation and (ii) azimuth angle for a satellite in geostationary orbit. ( $\mathbf{2} \boldsymbol{\times} \mathbf{5 = 1 0}$ marks)
- (b) What are the effects of non-spherical earth on a satellite? 5
- (c) What are the Keplerian orbital elements? Explain them. $\mathbf{5}$ OR
- (a) The orbit of an earth-orbiting satellite has an eccentricity of 0.15 and a semi major axis of 9000 km . Determine (i) its periodic time (ii) the apogee height (iii) the perigee height. Assume the mean radius of the earth to be 6371 km . ( $\mathb...
- (b) Outline the principle of Sun-synchronous orbits and Molniya orbits. What are the uses of Molniya orbits?
- (a) Draw the reliability model of a communication satellite and show that the reliability $R$ is given by, $$ R=1-\left(1-e^{\lambda t}\right)^{i} $$ where $1 / \lambda$ is the mean time between failures.
- (b) What is attitude control? Why is it needed? What are the techniques used for attitude control?
- (a) The earth to satellite path affects radio waves in several ways. Explain the role of propagation effects on the design of a satellite communication link. 10
- (b) Explain attenuation for transmission caused by rain. Derive an expression for rain attenuation in decibels.
- (c) What is the effect of rain on antenna noise?
- (a) Draw the frame structure of a TDMA system and explain the details.
- (b) Explain and write expressions for,
- (i) Transponder utilization in TDMA systems (ii) Frame efficiency of TDMA.
- (a) What is the principle of DS-CDMA? Explain with necessary theory.
- (b) Describe with help of diagrams, the code acquisition and tracking in DS-CDMA systems.
- (a) Explain the general configuration of an earth station with the help of a block diagram. List and explain the RF subsystems required for the earth station.
- (b) Compare the performance of the various types of tracking systems used in earth stations.
- (a) Explain the principle of GPS, clearly explaining how positioning is done and how timing error in the receiver is removed.
- (b) What are the different types of antennas used in satellite communication?10