Vidyavardhini's College of Engineering and Technology



Program: BE Electronics and Telecommunication Engineering Curriculum Scheme: Revised 2016Examination: Final Year Semester VIII Course Code: ECCDLO8043 and Course Name: Satellite Communication 1)Which of the following components receives, translates the signal frequency and re-transmits the signal in a satellite?Answera.Repeaterb.Relayc.TransponderCd.Transducer2)What is the number of transponders if the satellite uses 12 channels of frequency and frequency reuse is implemented?a.12b.6c.24Cd.33)In Rf tuning, what is the first local oscillator?a.Quartz oscillatorb.Frequency synthesizerc.Magnetic oscillatord.Electric oscillators4)What type of satellite TV service uses compressed data transmission to beam signals directly to every home?a.Direct broadcast satelliteb.Mobile satellite serviceAc.Broadcasting satellite serviced.Fixed satellite service5)Which frequency band does the direct broadcast satellite system use?a.C bandb.X bandc.Ku bandCd.MF band6)What is the number of satellites present in the Iridium system?a.72b.51c.66Cd.327)Which frequency band is used for connecting the satellite system with the public switched telephone network?a.L bandb.Ku bandc.C bandd.Ka bandD8)The noise power of any device becomes 0 whena.Absolute Temperature is 0Ab.Antenna gain is 0c.Transmitted power is 0d.Radiation Energy incident on the device is 09)An LNA is connected to a receiver which has a noise figure of 12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculate the overall noise temperature referred to the LNA input.a.120.43 KAb.150.21 Kc.140.2 Kd.125.5 K10)For a satellite circuit the individual link carrier-to-noise spectral density ratios are: uplink 100 dBHz; downlink 87 dBHz. Calculate the combinedC/N0 ratioa.67.89 dBHzb.89.67 dBHzc.79.86 dBHzd.86.79 dBHzD11)A satellite signal transmitted from a satellite transponder to earth’s station is called asa.Uplinkb.DownlinkBc.Terrestriald.Earth bound12)RFL occur due toa.Connection between receive antenna and receiverAb.Connection between mixer and amplifierc.Antenna misalignmentd.Connection between antenna and amplifier13)In Rf tuning, what is the first local oscillator?a.Quartz oscillatorb.Frequency synthesizerBc.Magnetic oscillatord.Electric oscillators14)Define S/N ratioa.The S/N introduced in the preceding section is used to refer to the ratio of signal power to noise power at the receiver output. This ratio is sometimes referred to as the post detector.b.The S/N introduced in the preceding section is used to refer to the ratio of signal power to noise power at the receiver input. This ratio is sometimes referred to as the post detector.Bc.Either of themd.None of above15)Unit of dbW is relative toa.1mWb.1WBc.1kWd.20W16)Calculate Noise Factor for a circuit having noise figure 16.23a.42Ab.23c.16d.5417)?Is a loss of power of a satellite downlink signal due to earth’s atmosphere.a. Atmospheric lossb. Path lossBc. Radiation lossd.RFI18)The equivalent Noise temperature for a system having Noise Factor 2, reference temperature 290K isa.290KAb.300Kc.580Kd.132K19)For global communication, the number of satellites needed isa.1b.3Bc.10d.520)For southern hemisphere, if ES is to east of satellite thena.A=180+A’b.A=A’c.A=360+A’d.A=360-A’D21)Autumn Equinox occurs neara.21 Decemberb.21 Marchc.21 SeptemberCd.21 August22)A single dipole will receive signal from circularly polarized wave at a loss ofa.0dBb3 dBBc.6dBd.9dB23)Which Law suggest that? “ the path followed by a satellite around the primary will be an ellipse “a.Keplers 1st law of satellite motionAb.Newtons third law of motionc.Keplers 2nd? law of satellite motiond.Keplers 3rd? law of satellite motion24)MEO orbits are located at?a.16-50km from surface of the earthb.1600-5000km from surface of the earthc.160-500km from surface of the earthd.10000-20000km from surface of the earthD25)What is the number of components of the vector that describes the translational motion of the vehicle?a.6Ab.3c.2d.126………… is considered as the unsolved problem in satellite system. a.Costb.Accessc.PrivacyCd.Coverage37The discussing sharing of a communication satellite by many geographically dispersed Earth station, DAMA meansa.Demand-Assigned Multiple AccessAb.Decibel Attenuated Microwave Accessc.Digital Analog Master Antennad.Dynamically-Assigned Multiple Access28Beam Switching by Transponder hopping is a solution of interconnection when :a.Number of Beams are Highb.Number of beams LowBc.Payload is Highd.Payload is Low29The duration of connection between an Up Beam and Down Beam is defined as a :a.Time slotb.Framec.WindowCd.Frequency slot30What is the process called when the state vector is calculated on board the vehicle?a.Navigationb.Guidancec.Surveillanced.Position location31Which type of navigation measure the state vector without regard to the path travelled by the vehicle in the past?a.Dead reckoningb.PositioningBc.Direct reckoningd.AHRS32Which one of the following does not fall under the positioning system?a.Radio systemsb.Celestial systemsc.AHRSCd.Mapping navigation systems33Which of the following navigational systems is most stealthy?a.Secondary surveillance radarb.VORc.Celestial navigationCd.SONAR34How is the velocity of an aircraft measured by passive radio systems?a.Doppler shiftAb.Velocity data is transmitted by the aircraft and received by the stationc.Secondary surveillance methodd.Satellite mapping35The distance the aircraft has to cover in the ground to achieve takeoff speed is called? a.Ground rollAb.Take off distancec.Runway lengthd.Airborne distance36The distance the aircraft climbs to clear an obstacle of particular height during takeoff is called as?a.Ground rollb.Take off distancec.Runway lengthd.Airborne distanceD37What is the take-off clearance height for a military aircraft?a.50ftAb.35ftc.20ftd.100ft38The velocity at which yawing motion can be produced by rudder deflection while the aircraft is on the ground is called _______a.Ground roll speedb.Ground control speedc.Minimum control speed on the groundCd.Control speed39For a satellite circuit the individual link carrier-to-noise spectral density ratios are: uplink 100 dBHz; downlink 87 dBHz. Calculate the combined C/N0 ratio.a.84.4 dBHzb.87.6 dBHzc.85.9 dBHzd.86.79dBHzD40The height at which approach is aborted when the runway is not in sight is called as?a.Decision heightAb.Approach altitudec.Clearance altituded.Landing altitude41What is Bandwidth available for? C band? : a.50 GHzb.50 MHzc.500 MHzCd.2? GHz42TV transmission isa.SimplexAb.Half Duplexc.Full Duplexd.None of the above43Winter solstice occurs neara.21 DecemberAb.24 Marchc.27 Decemberd.21 June44Which band is used for DBS TV system :a.C bandb.V bandc.VHFd.Ku BandD45In a typical mobile satellite array antenna if three elements are activated, how many elements are deactivated?a.3b.11Bc.5d.946For an equatorial orbit, movement of the satellite about the Yaw axis moves the antenna footprint:a. North and Southb. EAST and WestBc. North and Westd. South and East47The most common device used as an LNA isa.zener diodeb.tunnel diodeBc.IMPATTd.Shockley diode48?The radiation patterns of earth coverage antennas have a beamwidth of approximatelya.21?b.5?c.17?Cd.35?49What circuit is responsible in activating and deactivating adjacent antenna elements in a mobile satellite array?a.Radial dividerAb.Divider/combinerc.Radial combinerd.?Radial multiplexer50The frequency band used by most satellite isa.UHFb.VHFc.SHFCd.EHF51?It is the direction of maximum gain of the earth station antennaa.Footprintb.BoresightBc.Angle of elevationd.Angle of azimuth52What is meant by EIRP?a.Equivalent Isotropic Radiated PowerAb.Energy Isotropic Radiated Powerc.Equivalent Isotropic Resonance Powerd.Energy Isotropic Resonance Power53Which of the following is not usually a part of a transponder?a.LNAb.Mixerc.ModulatorCd.HPA54The satellite communications channel in a transponder are defined by thea.LNAb.Bandpass filterBc.Mixerd.Input signals55The standby units are also called asa.Guard band unitsb.Redundant unitsBc.Dispensable unitd.Unwanted unit56What is the PN sequence length for a PN sequence generated using a feedback register of length m=3 and chip rate 107 chips per second.a.3b.15Bc.7d.857Calculate the frame efficiency for an INTELSAT frame where overhead bits are 6144 and total bits are 120832.a.94.9 %Ab.50.84%c.99.4%d.84.50%58In some phase detection systems, the phase detector must be allowed for some time to receiver from one burst before the next burst receiving by it. The waiting time is known as______a.Preamble b.Guard time c.Frame efficiency d.Decoding quenchingD59Which of the following is not a typical output from the GPS receiver?a.Latitudeb.SpeedBc.Altituded.Longitude60The echo heard by a telephone user on a satellite channel can be removed by usinga.A vocoderb.A multiplexerc.Echo suppressorCd.Digital techniques61Satellite used for intercontinental communications are known asa.Domsatb.Marisatc.sat62In satellite communication, frequency modulation is used because satellite channel hasa.small bandwidth and negligible noiseb.large bandwidth and severe noiseBc.maximum bandwidth and minimum noised.high modulation index63Determine angle of tilt λE = 39°; aGSO= 42164 km; R= 6371 km; b=λE = 59°a.11.7 degreeAb.12.7 degreec.16 degreed.19 degree64Which of the following is not a satellite subsystem?a.Ground stationAb.Power systemc.Telemetry munication subsystem65The point where the orbit crosses the equatorial plane going from south to north is called as:a.Ascending NodeAb.Centre of earthc.Descending Noded.Argument of Perigee66The apogee distance from centre of earth for e=0.1 and semi-major axis 7000km isa.7000kmb.7700kmBc.35786kmd.42000km67In RF tuning, _________ provides the final up conversion to the microwave frequency?a.Fixed-frequency local oscillatorb.RF frequency synthesizerBc.Quartz oscillatord.Magnetic oscillator68For northern hemisphere, if ES is to east of satellite thena.A=180-A’b.A=180+A’Bc.A=360-A’d.A=360+A’69C – band of satellite communication ranges froma.2-3 GHzb.4-8GHzBc.8-12GHzd.12-16GHz70The point nearest from earth in satellite orbit is called as?a.Semi minor axisb.Apogeec.PerigeeCd.Eccentricity71The range between a ground station and a satellite is 43,000 km. Calculate the free-space loss at a frequency of 7 GHz.a.100.2dBb.150dBc.201.97dBCd.200.4 dB72A satellite stay in orbit because the following two factors are balanceda.Satellite weight and speedb. Gravitational force and centrifugal forceBc. Centripetal force and speedd.Satellite weight and the pull of the moon and sun73The jet thrusters are usually fired toa.maintain altitudeAb.put the satellite into the transfer orbitc.inject the satellite in the geosynchronous orbitd.bring the satellite back to earth.74The physical location of a satellite is determined by itsa.distance from the earthb.latitude and longitudeBc.reference to the starsd.position relative to the sun75Satellite that provide services within a single countrya. DomsatAb. Comsatc. Regionald. Global76The ________ angle measures the satellite position clockwise from the direction of true north.a.azimuthAb.elevationc.depressiond.critical77What is meant by GPRS ?a.General packet receiver serviceb.General packet radio serviceBc.Global packet radio serviced.Global packet receiver service78When individual up converters are used to modulate a channel, what is used to combine them into final signal?a.Microwave combinerAb.Multiplexerc.Mixerd.Amplifier79What provides the sufficient drive to the final power amplifier?a.Intermediate-power amplifierAb.Operational amplifierc.Power driver circuitd.Up converter80What technique does DSP use to double the number of channels by using helical antennas?a.Spatial isolationb.Frequency reuseBc.Multiplexingd.Modulation81Noise Power at 100K and BW of 10 MHz isa.1.38exp(-12)b.1.38exp(-13)c.1.38exp(-14)Cd.1.38exp(-15)82A satellite link operating at 14 GHz has receiver feeder losses of 1.5 dB and a free-space loss of 207 dB. The atmospheric absorption loss is 0.5 dB, and the antenna pointing loss is 0.5 dB. Depolarization losses may be neglected. Calculate the total link loss for clear-sky conditions.a.209.5dBAb.201.8dBc.205.9 dBd.208.4dB83The effective area of an isotropic antenna that operates at 14 GHZ.a.-34.7dBb.-44.37dBBc.44.37dBd.34.7dB84A satellite is operated at an EIRP of 56 dBW with an output BO of 6 dB. The transmitter feeder losses amount to 2 dB, and the antenna gain is 50 dB. Calculate the power output of the TWTA required for full saturated EIRP.a.16dBWb.15dBWc.14dBWCd.18dBW85Departure and approach are sub phases of what?a.Landing phaseb.Take off phasec.Terminal phaseCd.Surface phase86All satellites rotate around the earth in an orbit that forms a plane that passes through the center of gravity of earth called ____.a.Focusb.GeocenterBc.Orbitd.Center87In satellite communications, type of orbit which is virtually all orbits except those travel directly above the equator or directly over the North or the South poles.a.Equatorial orbitb.Polar orbitc.Geosynchronous orbitd.Inclined orbitD88It is the vertical angle formed between the direction of travel of an electromagnetic wave radiated from an earth station antenna pointing directly toward a satellite and the horizontal plane.a.Angle of depressionb.Angle of inclinationc.Angle of elevationCd.Angle of azimuth89It is the horizontal angular distance from a reference direction either the southern or northern most point of the horizon.a.Angle of elevationb.Latitudec.Longituded.AzimuthD90It is the angle between the earth’s equatorial plane and the orbital plane of the satellite measured counterclockwise.a.Angle of elevationb.Angle of azimuthc.Angle of inclinationCd. Angle of tetrahedron91The position of a satellite is measurea.by its elevation angle with respect to the horizonb.by its azimuth angle measured clockwise from the direction of true northc.through the line of apsidesd.by its elevation angle with respect to the horizon and its azimuth angle measured clockwise from the direction of true northD92An orbit when the satellite rotates in a path above the equator.a.Polar orbitb.Inclines orbitc.Equatorial orbitCd.Geosynchronous orbit93How does interference between uplink and downlink signals be prevented?a.By using different ground stationsb.By using different satellitesc.By using different carrier frequenciesCd.By different polarization94A satellite is orbiting in the equatorial plane with a period from perigee to perigee of 12 h. Given that the eccentricity is 0.002, calculate the semimajor axis. The earth’s equatorial radius is 6378.1414 km.a.25532Kmb.26610KmBc.21610Kmd.23532Km95In satellite communication, frequency modulation is used because satellite channel hasa.small bandwidth and negligible noiseb.large bandwidth and severe noiseBc.maximum bandwidth and minimum noised.high modulation index96Phase modulation is commonly-used for data transmission mainly because a.phase can be varied from + 180° to 180°b.it gives highest data rates that can be transmitted over a given channelc.demodulation is very easyd.it is resistant to the effects of noiseD97Which of the following amplifiers is used in the transmitter substation?a.RF amplifiersb.Buffer amplifiersc.Klystron amplifierCd.Operational amplifiers98The transmit and receive signals are separated in a device known as a.diplexerAb.modulatorc.demodulatord.LNA99An LNA is connected to a receiver which has a noise figure of 12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculate the overall noise temperature referred to the LNA input.a.125.2Kb.118.4Kc.120.43KCd.122.3K100For a satellite circuit the individual link carrier-to-noise spectral density ratios are: uplink 101.5 dBHz; downlink 93.2 dBHz. Calculate the combined C/N0 ratio.a.91.45 dBHzb.93.5 dBHzc.94.6 dBHzd.92.6 dBHzD ................
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