8/12/2019 SC Papers

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SET-1RRCode No: RR410406

B.Tech IV Year I Semester Examinations, December-2011SATELLITE COMMUNICATIONS

(ELECTRONICS AND COMMUNICATION ENGINEERING) Time: 3 hours Max. Marks: 80

Answer any five questionsAll questions carry equal marks

---1.a) Satellite communications have lots of advantages over terrestrial communications.

List all the advantages and discuss in brief. b) State Keplers laws of orbital motion.c) Explain what is meant by the geostationary orbit? How does this orbit differ from

geosynchronous orbit? [4+6+6]

2.a) List the frequency band designations in common use for Satellite services. What isthe basis on which the Satellite frequencies are selected? Justify why uplinkfrequency has to be greater than down link frequency.

b) Prove that the maximum duration of Satellite eclipse is 70 minutes. [8+8]

3.a) With the help of a neat block schematic, explain earth segment of a Satellitecommunication link.

b) In a communication Satellite, power supply system is an important subsystem.Explain about it, in detail. [10+6]

4.a) A Satellite at a distance of 36,000 km, from a point on the surface of earth, radiates a power of 2 Watts from an antenna with a gain of 17 dB in the direction of anobserver. Find the flux density at the receiving point and the power received by anantenna with an effective area of 10 m 2.

b) The earth subtends an angle of 17 0 when viewed from geostationary orbit. What arethe dimensions and gain of a horn antenna that will provide global coverage at 4GHz? [9+7]

5.a) Derive the general link design equation. Find out the expression for G/T ratio. b) Explain the concept of Frequency-reuse and how it can be implemented in

Satellite communication.c) Differentiate Noise temperature and Noise figure. [8+4+4]

6.a) With the help of neat schematic diagrams, explain in detail about:(i) TDMA (ii) FDMA (iii) CDMA.

b) Write a note on direct broadcast Satellites. [10+6]

7.a) A 3-meter diameter earth station antenna of circular aperture is used to receiveSatellite signals in the 4 GHz band. The system noise figure is 1 dB. Calculate theG/T ratio of the earth station. Express the answer in dBK -1.

b) A low noise amplifier (LNA) is connected to a receiver which has a noise figure of12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculatethe overall noise temperature referred to the LNA input. [8+8]

8.a) With the aid of a block schematic, describe the functioning of transmit-receiveearth station.

b) An earth station radiates an equivalent isotropic radiated power of 54 dBW at 14 GHzfrom a 10-m parabolic antenna. The transmit feeder losses between the high-poweramplifier (HPA) and the antenna are 2.5 dB. Calculate the output of the HPA.[10+6]

******

8/12/2019 SC Papers

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SET-2RRCode No: RR410406

B.Tech IV Year I Semester Examinations, December-2011SATELLITE COMMUNICATIONS

(ELECTRONICS AND COMMUNICATION ENGINEERING) Time: 3 hours Max. Marks: 80

Answer any five questionsAll questions carry equal marks

---1.a) With the help of a neat block schematic, explain earth segment of a Satellite

communication link. b) In a communication Satellite, power supply system is an important subsystem.

Explain about it, in detail. [10+6]

2.a) A Satellite at a distance of 36,000 km, from a point on the surface of earth, radiates a power of 2 Watts from an antenna with a gain of 17 dB in the direction of anobserver. Find the flux density at the receiving point and the power received by anantenna with an effective area of 10 m 2.

b) The earth subtends an angle of 17 0 when viewed from geostationary orbit. What arethe dimensions and gain of a horn antenna that will provide global coverage at 4GHz? [9+7]

3.a) Derive the general link design equation. Find out the expression for G/T ratio. b) Explain the concept of Frequency-reuse and how it can be implemented in

Satellite communication.c) Differentiate Noise temperature and Noise figure. [8+4+4]

4.a) With the help of neat schematic diagrams, explain in detail about:(i) TDMA (ii) FDMA (iii) CDMA.

b) Write a note on direct broadcast Satellites. [10+6]

5.a) A 3-meter diameter earth station antenna of circular aperture is used to receiveSatellite signals in the 4 GHz band. The system noise figure is 1 dB. Calculate theG/T ratio of the earth station. Express the answer in dBK -1.

b) A low noise amplifier (LNA) is connected to a receiver which has a noise figure of12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculatethe overall noise temperature referred to the LNA input. [8+8]

6.a) With the aid of a block schematic, describe the functioning of transmit-receiveearth station.

b) An earth station radiates an equivalent isotropic radiated power of 54 dBW at 14 GHzfrom a 10-m parabolic antenna. The transmit feeder losses between the high-poweramplifier (HPA) and the antenna are 2.5 dB. Calculate the output of the HPA.[10+6]

7.a) Satellite communications have lots of advantages over terrestrial communications.List all the advantages and discuss in brief.

b) State Keplers laws of orbital motion.c) Explain what is meant by the geostationary orbit? How does this orbit differ from

geosynchronous orbit? [4+6+6]

8.a) List the frequency band designations in common use for Satellite services. What isthe basis on which the Satellite frequencies are selected? Justify why uplinkfrequency has to be greater than down link frequency.

b) Prove that the maximum duration of Satellite eclipse is 70 minutes. [8+8]******

8/12/2019 SC Papers

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SET-3RRCode No: RR410406B.Tech IV Year I Semester Examinations, December-2011

SATELLITE COMMUNICATIONS(ELECTRONICS AND COMMUNICATION ENGINEERING)

Time: 3 hours Max. Marks: 80Answer any five questions

All questions carry equal marks---

1.a) Derive the general link design equation. Find out the expression for G/T ratio. b) Explain the concept of Frequency-reuse and how it can be implemented in

Satellite communication.c) Differentiate Noise temperature and Noise figure. [8+4+4]

2.a) With the help of neat schematic diagrams, explain in detail about:(i) TDMA (ii) FDMA (iii) CDMA.

b) Write a note on direct broadcast Satellites. [10+6]

3.a) A 3-meter diameter earth station antenna of circular aperture is used to receiveSatellite signals in the 4 GHz band. The system noise figure is 1 dB. Calculate theG/T ratio of the earth station. Express the answer in dBK -1.

b) A low noise amplifier (LNA) is connected to a receiver which has a noise figure of12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculatethe overall noise temperature referred to the LNA input. [8+8]

4.a) With the aid of a block schematic, describe the functioning of transmit-receiveearth station.

b) An earth station radiates an equivalent isotropic radiated power of 54 dBW at 14 GHzfrom a 10-m parabolic antenna. The transmit feeder losses between the high-poweramplifier (HPA) and the antenna are 2.5 dB. Calculate the output of the HPA.[10+6]

5.a) Satellite communications have lots of advantages over terrestrial communications.List all the advantages and discuss in brief.

b) State Keplers laws of orbital motion.c) Explain what is meant by the geostationary orbit? How does this orbit differ from

geosynchronous orbit? [4+6+6]

6.a) List the frequency band designations in common use for Satellite services. What isthe basis on which the Satellite frequencies are selected? Justify why uplinkfrequency has to be greater than down link frequency.

b) Prove that the maximum duration of Satellite eclipse is 70 minutes. [8+8]

7.a) With the help of a neat block schematic, explain earth segment of a Satellitecommunication link.

b) In a communication Satellite, power supply system is an important subsystem.Explain about it, in detail. [10+6]

8.a) A Satellite at a distance of 36,000 km, from a point on the surface of earth, radiates a power of 2 Watts from an antenna with a gain of 17 dB in the direction of anobserver. Find the flux density at the receiving point and the power received by anantenna with an effective area of 10 m 2.

b) The earth subtends an angle of 17 0 when viewed from geostationary orbit. What arethe dimensions and gain of a horn antenna that will provide global coverage at 4GHz? [9+7]

******

8/12/2019 SC Papers

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B.Tech IV Year I Semester Examinations, December-2011

SET-4RRCode No: RR410406

SATELLITE COMMUNICATIONS(ELECTRONICS AND COMMUNICATION ENGINEERING)

Time: 3 hours Max. Marks: 80Answer any five questions

All questions carry equal marks---

1.a) A 3-meter diameter earth station antenna of circular aperture is used to receiveSatellite signals in the 4 GHz band. The system noise figure is 1 dB. Calculate theG/T ratio of the earth station. Express the answer in dBK -1.

b) A low noise amplifier (LNA) is connected to a receiver which has a noise figure of12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculatethe overall noise temperature referred to the LNA input. [8+8]

2.a) With the aid of a block schematic, describe the functioning of transmit-receiveearth station.

b) An earth station radiates an equivalent isotropic radiated power of 54 dBW at 14 GHzfrom a 10-m parabolic antenna. The transmit feeder losses between the high-power

amplifier (HPA) and the antenna are 2.5 dB. Calculate the output of the HPA.[10+6]

3.a) Satellite communications have lots of advantages over terrestrial communications.List all the advantages and discuss in brief.

b) State Keplers laws of orbital motion.c) Explain what is meant by the geostationary orbit? How does this orbit differ from

geosynchronous orbit? [4+6+6]

4.a) List the frequency band designations in common use for Satellite services. What isthe basis on which the Satellite frequencies are selected? Justify why uplinkfrequency has to be greater than down link frequency.

b) Prove that the maximum duration of Satellite eclipse is 70 minutes. [8+8]

5.a) With the help of a neat block schematic, explain earth segment of a Satellitecommunication link.

b) In a communication Satellite, power supply system is an important subsystem.Explain about it, in detail. [10+6]

6.a) A Satellite at a distance of 36,000 km, from a point on the surface of earth, radiates a power of 2 Watts from an antenna with a gain of 17 dB in the direction of anobserver. Find the flux density at the receiving point and the power received by anantenna with an effective area of 10 m 2.

b) The earth subtends an angle of 17 0 when viewed from geostationary orbit. What arethe dimensions and gain of a horn antenna that will provide global coverage at 4GHz? [9+7]

7.a) Derive the general link design equation. Find out the expression for G/T ratio. b) Explain the concept of Frequency-reuse and how it can be implemented in

Satellite communication.c) Differentiate Noise temperature and Noise figure. [8+4+4]

8.a) With the help of neat schematic diagrams, explain in detail about:(i) TDMA (ii) FDMA (iii) CDMA.

b) Write a note on direct broadcast Satellites. [10+6]******