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View File - University of Engineering and Technology, Taxila

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Satellite:Frequencies:14.75 GHz up <strong>and</strong>11.36 GHz downAntennas: 1.425 beamwidth up <strong>and</strong> down (Note that this is 3-dBmeasurement.)Transponder:B<strong>and</strong>width ¼ 50 MHz.Saturated output power ¼ 20.02 W.Input noise temperature ¼ 226.5 C.Gain (up to point <strong>of</strong> saturation) ¼ 119.2 dB.Path losses in benign environment:201 dB at 14.75 GHz195 dB at 11.36 GHzEarth station:Antenna:Diameter 3 mAperture efficiencies:64.5% at 1.47 GHz 61.25% at 11.36 GHzOhmic loss between the antenna <strong>and</strong> LNA ¼ 1dBReceiver (IF) b<strong>and</strong>width ¼ 50 MHz.Calculate the transmitter power required to just saturate the transponderoutput amplifier for an earth station at the edge <strong>of</strong> thecoverage zone <strong>of</strong> the satellite antenna. Ignoring any noise contributionsfrom the satellite transponder, estimate (i) the earthstation’s G=T required to give a carrier-to-noise ratio <strong>of</strong>17.92 dB in the earth station IF amplifier <strong>and</strong> (ii) the earth stationnoise temperature allowing for a loss figure <strong>of</strong> 0.5 dB.Find the carrier-to-noise ratio in the transponder when its output isjust saturated. Also find the carrier-to-noise ratio in the earthreceiver IF amplifier when the transponder noise is included.2. A satellite carrying a 9.8-GHz continuous-wave beacon transmitter islocated in geosynchronous orbit 37,586 km from an earth station. Thebeacon’s output power is 0.3 W <strong>and</strong> feeds an antenna <strong>of</strong> 19-dB gain towardthe earth station. The antenna is 3.65 m in diameter with an apertureefficiency <strong>of</strong> 62.5%.(i)(ii)(iii)Calculate the satellite EIRP.Calculate the receiving antenna gain.Calculate the path loss.Copyright © 2002 by Marcel Dekker, Inc. All Rights Reserved.

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