satellite communications finals.pptx

8/21/2019 Satellite Communications Finals.pptx

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SatelliteCommunications

Engr. Leah Q. Santos

Faculty, Eng’g-EcE dept.


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Satellite Link Models Uplink Model


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Satellite Link Models Transponder


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Satellite Link Models Downlink Model


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Satellite Link Models Cross-Links – also known as

intersatellite links (ISLs)


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Satellite System

arameters

Back – Of - reduction o! input power toreduce the amount o! intermodulation

distortion caused "y the nonlinearampli#cation o! $%

Back – Of Loss (Lbo ) – the amount o!"acked-o& !rom rated le'els .

Satrated otpt !ower(!o(sat)or !t )-output power o! a typical satellite earthstation e(pressed in d)*.


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Satellite System

arameters"!# inpt$otpt c%aracteristic cr&e


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Satellite System

arameters Satrated otpt !ower(!o(sat)or !t )- output

power o! a typical satellite earth station .

where+

E" energy o! a single "it /"it0

t total saturated power * or /sec0

1" time o! a single "it sec0


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E(ample+For a total transmit power o! 3444 *,determine the energy per "it in d) !or atransmission rate o! 54 M"ps.

%nswer+ -67 d)


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Satellite System

arameters 'fecti&e Isotropic adiated !ower

('I!)- an e8ui'alent transmit powerand is e(pressed as+

where+E9: E&ecti'e 9sotropic :adiated ower *0

in antenna input power*0

%t transmit antenna gainunitless ratio0


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E(ample+For an earth station transmitter with an antennaoutput power o! 64 d)*, a "ack-o& loss o! ; d),a total "ranching and !eeder loss o! ; d), and atransmit antenna gain o! 64 d), determine theE9:.

%nswer+ 76 d)*


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Seatwork+For an earth station transmitter has an $% witha rated saturated power o! 34,444*. % "ack-o&loss o! < d), a total "ranching loss o! = d),!eeder loss o! 6 d), and a transmit antenna gaino! 64 d), determine the E9:.

%nswer+ d)*


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Satellite System

arameters 'i&alent *oise Te+peratre(Te)

* , TB

*here+

? total noise power watts0

@ )oltAmann’s constant oules/@el'in0

) "andwidth hertA0

1 temp o! the en'ironment @el'in0

F 3 B 1e 1F-30

*here+

1e e8ui'alent noise temperature kel'in0

F noise !actor unitless0

1 temp. o! the en'ironment kel'in0


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Satellite System

arameters


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E(ample+ Con'ert noise #gures o! 6 d) and 6.3d)

to e8ui'alent noise temperatures. se;44 @ !or the en'ironmental temperature.

%nswer+ 65;.< @ and 673 @


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Satellite System

arameters *oise Densit. (*o)- the noise power normaliAed

to a 3- $A "andwidth, or the noise power presentin a 3-$A "andwidth.

/%ere0

?o - noise density watts/hertA Doule/cycle0

? total noise power watts0

) "andwidth hertA0

@ )oltAmann’s constant Doule/kel'in0 1e e8ui' noise temperature kel'in0

?od"*/$A0 34 log ? -34 log )

34 log @ B 34 log 1e


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Satellite System

arameters Carrier-to-*oise Densit. atio (C$*o) – the

a'erage wide"and carrier power-to-noisedensity ratio.

/ideband carrier power – the com"ined powero! the carrier and its associated side"ands.


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Satellite System

arameters 'ner1. o2 Bit-to-*oise Densit. atio('b$*o)

–one o! the most important and most o!tenused parameters when e'aluating a digital radiosystem.

- a con'enient way to compare digital systemsthat use di&erent transmission rates, modulationschemes, or encoding techni8ues.


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Satellite System

arameters 'ner1. o2 Bit-to-*oise Densit. atio('b$*o)

–one o! the most important and most o!tenused parameters when e'aluating a digital radiosystem.

- a con'enient way to compare digital systemsthat use di&erent transmission rates, modulationschemes, or encoding techni8ues.


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Satellite System

arameters


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Satellite System

arameters


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E(ample+ % coherent )S@0 transmitter operates

at a "it rate o! =4 M"ps. For apro"a"ility error o! 34e(p-6s


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ain-1o-E8ui'alent ?oise

1emperature :ation 3ain-to-ei&alent noise te+peratre

ratio(3$Te) – a #gure o! merit used to representthe 8uality o! a satellite or earth stationrecei'er.

/%ere0

3, recei'e antenna gaind)0

Ts, operating or system temp.G@0Ta, antenna temp. G@0

Tr, recei'er e&ecti'e input noise temp. G@0


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Satellite SystemLink E8uations


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nplink E8uation+

E9: earth Free-space satellite additional)oltAmann’s

station path loss /1e atmospheric

constant

Losses


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Hownlink E8uation+

E9: earth Free-space satellite additional)oltAmann’s

station path loss /1e atmospheric

constant

Losses


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E(ample+

Complete the link"udget !or asatellite systemwith the !ollowing

parameters+

a. E9:

". C/?o

c. C/?

d. E"/?o

e. E"/?o o'erall0


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Formulas+


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%ssignment+ Chapter =5 page 36I

1)SJ + 1uesday March ;,=435

satellite communications finals.pptx

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