Gujarat Technological University 2010 M.E Electronics and Telecommunications Technival University - - Question Paper
Seat No.: _____ Enrolment No.______
GUJARAT TECHNOLOGICAL UNIVERSITY
M.E Sem-II exam July 2010
Subject code: 710418 Subject Name: Satellite Communication
Date: 10 / 07 /2010 Time: 11.00am – 1.30pm
Total Marks: 60
Instructions:
1. Attempt all ques..
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) describe the subsequent terms:
(i) Apogee (ii) Perigee (iii) Inclination (06)
(b) State Kepler's 3 laws of planetary motion. (06)
Q.2 (a) discuss why there is only 1 geostationary orbit. Derive the formula to obtain range of a
geostationary satellite from an earth station in terms of Earth's radius, height of
geostationary orbit above the equator and elevation angle of earth station antenna. (06)
(b) An earth station is located at latitude 30° S and longitude 130° E.Calculate the antenna-
look angles for a satellite at 156° E. (06)
OR
(b) compute for your home location the look angles needed to receive from the satellite
immediately east of your longitude. (06)
Q.3 (a) A geostationary satellite stationed at 90° W transmits a vertically polarized wave.
Determine the polarization of the resulting signal received at an earth station situated
at 70° W, 45° N. (06)
(b) Briefly define the three- axis method of satellite stabilization. (06)
OR
Q.3 (a) Draw to scale the uplink and downlink channeling schemes for a 500 MHz bandwidth C-band
satellite, accommodating the full complement of 36-MHz bandwidth transponders. presume the
use of four MHz guard bands. (06)
(b) discuss what is meant by thermal control and why it is necessary in a satellite. (06)
Q.4 (a) define and compare MATV and CATV systems. (06)
(b) define the antenna subsystem in the space segment. (06)
OR
Q.4(a)Calculate the gain of a 3-m parabolic reflector antenna at a frequency of six GHz and 14GHz.(06)
(b) describe noise factor. The noise factor of an amplifier is 7:1 .Calculate noise figure and
equivalent noise temperature. (06)
Q.5 (a) discuss what is meant by carrier-to- noise ratio? At the input to a receiver,the received carrier power is 40 pW and the system noise temperature is 450K. compute the Carrier-to-noise density ratio in dBHz. provided the bandwidth 0f 36MHz, compute C/N ratio in dB. (06)
(b) discuss the need for a reference burst in a TDMA system. (06)
OR
Q.5 (a) discuss input and output back-off in power amplifier. (06)
(b) The EIRP of every earth station in an FDMA network is 47 dBW and the input data rate are at the one bit rate with 7/8 FEC added. The downlink bit rate is limited maximum of 60 Mbps with 6-dB output back-off applied. Compare the EIRP needed for the earth station in a TDMA network utilizing the identical transponder. (06)
Seat No. Enrolment No.
GUJARAT TECHNOLOGICAL UNIVERSITY
M.E Sem-II Examination July 2010 Subject code: 710418 Subject Name: Satellite Communication
Date: 10 / 07 /2010 Time: 11.00am - 1.30pm
Total Marks: 60
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define the following terms:
06
06
06
(i) Apogee (ii) Perigee (iii) Inclination (b) State Keplers three laws of planetary motion.
Q.2 (a) Explain why there is only one geostationary orbit. Derive the equation to find range of a geostationary satellite from an earth station in terms of Earths radius, height of geostationary orbit above the equator and elevation angle of earth station antenna.
(b) An earth station is located at latitude 30 S and longitude 130 E. Calculate the antenna-look angles for a satellite at 156 E.
06
OR
(b) Calculate for your home location the look angles required to receive from the satellite immediately east of your longitude.
06
Q.3 (a) A geostationary satellite stationed at 90 W transmits a vertically polarized wave. Determine the polarization of the resulting signal received at an earth station situated at 70 W, 45 N.
06
(b) Briefly describe the three- axis method of satellite stabilization. 06
OR
Q.3 (a) Draw to scale the uplink and downlink channeling schemes for a 500 06 MHz bandwidth C-band satellite, accommodating the full complement of 36-MHz bandwidth transponders. Assume the use of 4 MHz guard bands.
(b) Explain what is meant by thermal control and why it is necessary in a 06 satellite.
Q.4 (a) Describe and compare MATV and CATV systems. 06
(b) Describe the antenna subsystem in the space segment. 06
OR
Q.4 (a) Calculate the gain of a 3-m parabolic reflector antenna at a frequency of 6 06 GHz and 14 GHz.
(b) Define noise factor. The noise factor of an amplifier is 7:1 .Calculate 06 noise figure and equivalent noise temperature.
Q.5 (a) Explain what is meant by carrier-to- noise ratio? At the input to a receiver 06 ,the received carrier power is 40 pW and the system noise temperature is 450 K. Calculate the Carrier-to-noise density ratio in dBHz. Given the bandwidth of 36 MHz, calculate C/N ratio in dB.
(b) Explain the need for a reference burst in a TDMA system. 06
OR
Q.5 (a) Explain input and output back-off in power amplifier. 06
(b) The EIRP of each earth station in an FDMA network is 47 dBW and the 06 input data rate are at the T1 bit rate with 7/8 FEC added. The downlink bit rate is limited to a maximum of 60 Mbps with 6-dB output back-off applied. Compare the EIRP needed for the earth station in a TDMA network utilizing the same transponder.
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