B.TECH - Semester 8 satellite communications Question Paper 2013 (apr)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- What is meant by line of apsides and line of nodes?
- What is sun transit outage?
- Define antenna pointing loss.
- State the ways by which rainfall degrades the received $\left[\mathrm{C} / \mathrm{N}_{0}\right]$.
- What is power limited transponder?
- A satellite link in clear sky is using 8-PSK modulation scheme. It is needed to change the modulation scheme to counter the rain fade. Find out which modulation scheme is suitable : 4-PSK or 16-PSK and justify your answer.
- Define the terms telephone load activity factor and digital speech interpolation.
- A $70-\mathrm{MHz}$ carrier is frequency modulated by a $1-\mathrm{kHz}$ tone of 5 V peak amplitude. The frequency deviation constant is $15 \mathrm{kHz} / \mathrm{V}$. Use Carson's rule to estimate the bandwidth required. P.T.O.
- State the need for a Hub with large antenna in a VSAT network.
- What are the types of antenna losses? ( $10 \times 2=20$ Marks) Answer any one full questions from each Module.
- State Kepler's three laws of planetary motion. Illustrate in each case their relevance to artificial satellites orbiting the earth.
- (a) Write short notes on station keeping. 10
- (b) Explain about frequency allocations for satellite services.
- (a) An RF amplifier has 20 dB gain and 1 GHz bandwidth. Hot and cold load temperatures ( $T_{1}$ and $T_{2}$ ) and corresponding amplifier output powers ( $\mathrm{N}_{1}$ and $\mathrm{N}_{2}$ ) were measured as at $\mathrm{T}_{1}=290 \mathrm{~K}, \m...
- (b) A satellite at a distance of 40000 Km from a point on the Earth's surface radiates a power of 2 Watts from an antenna with a gain of 17 dB in the direction of the observer. Find the power received by an antenna with an effective area of $10 \math...
- A multiple carrier satellite Transponder operating at 6 GHz uplink and 4 GHz downlink has Transponder Saturation Flux Density $=-67.5 \mathrm{dBW} / \mathrm{m}^{2}$ and corresponding saturated EIRP $=26.6 \mathrm{dBW}$. The transponder is operating a...
- (a) Explain the principle behind spectrum spreading and despreading and how this is used to minimize interference in a CDMA system.
- (b) Describe how signal acquisition and tracking are achieved in a DS/SS system. OR
- Discuss briefly how demand assignment may be implemented in a TDMA network. What is the advantage of TDMA over FDMA in this respect?
- (a) Describe the main features of Radarsat. Explain what is meant by a "dawn to dusk" orbit and why the Radarsat follows such an orbit.
- (b) Write brief notes on the advantages and disadvantages of onboard switching and routing compared to the "bent pipe" mode of operation for satellite mobile communications.
- (a) Write the steps involved in the Satellite Communication Link Design procedure.
- (b) Explain remote sensing satellite in detail. ( $4 \times 20=80$ Marks)