microwave communication system

7/25/2019 Microwave Communication System

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A L M A C H R I S T I N E C . D A N Z A L A N , E C E

MICROWAVE

COMMUNICATION SYSTEM


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Introduction

Microwavesare the ultrahigh, superhigh, andetre!el" high #re$uencies directl" a%o&e thelo'er #re$uenc" ranges 'here !ost radio

co!!unication no' ta(es place and %elo' theoptical #re$uencies that co&er in#rared, &isi%le,and ultra&iolet light)


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Micro'a&e #re$uenc" %ands


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Microwave Radio-FrequencyAssignments

Band Frequency (GHz) Application

L 1 2

S 2 4 Marine radar

C 4 Co!!ercial u"e#

"atellite"

$ 12 Military

%u 12 1 Co!!ercial u"e#"atellite"

% 1 2& Co!!ercial u"e#"atellite"

%a 2& 4' Military

' '

* ' 1''


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ENG VAN

GMA EDSACOMPLEX

PLDT

SAMPALOC

TANDANG SORATRANSMIITTER

DOMSAT ANTIPOLO (TO

BE TRANSFERRED TO

NBC TOWER)

OB VAN

Micro+a,eCo!!unicationSet-up


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Applications*

A !icro'a&e o&en#or the purpose o# coo(ing#ood)

Micro'a&es are used in%roadcastingtrans!issions

Radaralso uses !icro'a&e radiation

Wireless +ANprotocols, such as luetoothand the IEEE-./)00gand%

speci#ications Metropolitan Area Net'or(s1 MAN protocols, such asWiMA2%ased

in the IEEE-./)03speci#ication

Ca%le TVand Internetaccess

Mo%ile phone net'or(s

Man" se!iconductor processingtechni$ues use!icro'a&es to generate plas!a#or such purposes asreacti&e ion etchingand 4ECV5)
http://en.wikipedia.org/wiki/Microwave_ovenhttp://en.wikipedia.org/wiki/Cookinghttp://en.wikipedia.org/wiki/Broadcastinghttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Wireless_LANhttp://en.wikipedia.org/wiki/Protocol_(computing)http://en.wikipedia.org/wiki/Bluetoothhttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/802.11ghttp://en.wikipedia.org/wiki/802.11bhttp://en.wikipedia.org/wiki/Metropolitan_Area_Networkhttp://en.wikipedia.org/wiki/WiMAXhttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/802.16http://en.wikipedia.org/wiki/Cable_TVhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Fabrication_(semiconductor)http://en.wikipedia.org/wiki/Plasma_physicshttp://en.wikipedia.org/wiki/Reactive_ion_etchinghttp://en.wikipedia.org/wiki/Reactive_ion_etchinghttp://en.wikipedia.org/wiki/Plasma_physicshttp://en.wikipedia.org/wiki/Fabrication_(semiconductor)http://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Cable_TVhttp://en.wikipedia.org/wiki/802.16http://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/WiMAXhttp://en.wikipedia.org/wiki/Metropolitan_Area_Networkhttp://en.wikipedia.org/wiki/802.11bhttp://en.wikipedia.org/wiki/802.11ghttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/Bluetoothhttp://en.wikipedia.org/wiki/Protocol_(computing)http://en.wikipedia.org/wiki/Wireless_LANhttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Broadcastinghttp://en.wikipedia.org/wiki/Cookinghttp://en.wikipedia.org/wiki/Microwave_oven


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I!portant considerations

Signals #ollo' a straight line or +ine o# Sight 6+OS7path)

Signals are a##ected %" o%structions 6Man1!ade

o%8ects, earth9s terrain7 and 'eather:at!osphericconditions 6#ree space attenuation7;

Installed in tall to'ers, %uildings or !ountains

Rela" can etend across countr" and continents)


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I!portant considerations

Tight %ea!, high #re$uenc";

?co&ering U>< and E>< range 6actuall"

%et'een 0 to 0.. @>7)Micro'a&e s"ste! capacities &ar" #or! 0/ to //...

&oice channels) 4resentl", !icro'a&e s"ste!s carr"pulse code !odulated ti!e di&ision !ultipleed

&oice %and circuits and use !ore !odern digital!odulation techni$ues, such as phase shi#t (e"ingand $uadrature a!plitude !odulation)


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Types of Microwave Transmission Link

Short Haulusuall" at lo'er capacit" ranging #ro! 3B(%ps up to /M%ps)

Long Haulused #or %ac(%one route applications at=B M%ps to 3/. M%ps capacit")


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Pre-

emphasisNetwork

FMDeviator

Mixer B.F

Microwave

Generator

C

h

a

n

n

e

l

c

om

b

i

n

i

n

g

N

e

t

wo

r

k

Ba"e/and

(audio#data#,ideo)

(0F out


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System variables for permissible distances between the transmitter

and its associated receiver:1. Transmitter output power

2. Receiver Noise threshold

3. Terrain

4. Atmospheric condition

5. System Capacity

. Relia!ility o!"ectives

#. $er%ormance e&pectation


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C+ASSI


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Categories o# Micro'a&e

0) +ine o# Sight Co!!unication

Use lo' trans!it po'er and highl" directionalantennas

Su%8ect to earth %ulge and other o%structions Mai!u! distance is =. to . statute !iles


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Categories o# Micro'a&e

/) Tropospheric Scatter Co!!unications Re$uires &er" high po'ered %ea! o# energ"

e"ond +OS

Uses re#racti&e properties 4ro&ides relia%le co!!unications up to B..

statute !ile


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Terres!ria" Microwave

asicall" there are / t"pes o# !icro'a&e stations) Ter!inalsD are points in the s"ste! 'here the

%ase%and signals either originate or ter!inate

RepeatersD are points in the s"ste! 'here the%ase%and signals !a"%e recon#igured or si!pl"repeated or a!pli#ied)


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Types of passive repea!ers

0) T'o identicalpara%olic antennas

placed %ac( to %ac(


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Types of passive repea!ers

/) A #lat %ill%oard t"peFre#lecting sur#ace)

1 #lat !etal t"pe used tore#lect !icro'a&e

signals


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T"pes o#


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T"pes o#


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Micro'a&e and >< Wire 5ipole Voltage:current

=. D =..M>

Micro'a&e Wa&eguide 4ara%olic:>orn

Electro!agnetic'a&es

0 D =. @>


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TY4ES O< MICROWAVE 4AT>

0) +ine1o#1Sight 4ath

/)@raing 4ath

=) O%structed 4ath


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C>ARACTERISTICS O< MICROWAVE

0) Micro'a&es %eha&e si!ilarl" as light 'a&es)

/) It can %e re#lected, re#racted and di##racted)

=) It can %e a%sor%ed %" so!e o# the particles in the

at!osphere)B) It can %e scattered)

) It can %e polaried)


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5i&ersit"

It suggests that there are !ore than onetrans!ission path or !ethod o# trans!ission

%et'een a trans!itter and the recei&er)

It can select the path or !ethod that gi&es thehighest $ualit" o# recei&ed signal)


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5i&ersit" Techni$ues

Space di&ersit"


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Space 5i&ersit"

addition o# another recei&e antenna,separated indistance #ro! the #irst

1 i!pro&e!ent in relia%ilit" co!es #ro! the reduced

pro%a%ilit" that %oth paths 'ill %e ad&ersel" a##ected%" #ading at the sa!e ti!e

1 !ore &ertical spacing %et'een antennas o##ers lesspath correlation and %etter path relia%ilit"


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Space di&ersit"


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Space diversity scheme: ntennaSeparation !S"

S = 3Re/ L

#here: $ %

path len&th

'e % e((ectiveearth radi)s !m"


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Space di&ersit"


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Other 5i&ersit" Techni$ues*

Cross%and di&ersit" Dthe signals are trans!itted usingentirel" di##erent allocations)

>"%rid 5i&ersit" D co!%ination o# space and #re$uenc"di&ersit"

4olariation 5i&ersit" D a single R< carrier is propagated'ith / di##erent electro!agnetic polariations 6Verticaland horiontal7

Angle di&ersit" D trans!ission o# in#or!ation at t'o or!ore slightl" di##erent angles resulting to t'o or !orepaths %ased on illu!inating di##erent scatter &olu!e introposcater s"ste!)


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Other 5i&ersit" Techni$ues

4ath 5i&ersit" D in this !ethod, the signal is sent toa lin( 'hich connects to the original destination, %utis not as se&erel" a##ected %" #ade)


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5egree o# 5i&ersit"

It descri%es the nu!%er o# signals carr"ing the sa!ein#or!ation a&aila%le at the recei&er)

5egree o# di&ersit" are*

0) 5ual di&ersit"/) Triple di&ersit"

=) Huad di&ersit"


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+ro!ec!ion Swi!cin'

/ T"pes o# protection s'itching e$uip!ent

0) >ot Stand%"

/) 5i&ersit"


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Ho! S!an-y/

Receiver

System XMR

Primary !"

System XMR

Stan#by !$

failure switch

%ctive RC&R

!"

Stan#by RC&R

!$

ransmitter

*Hot standby is designed for equipment failure

only


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Ear!0s c*rva!*re presen!s L$S os!r*c!ion an-m*s! e compensa!e- *sin' 123 ear! ra-i*s for

a!mosperic en-in' of waves.

Ear! #4"'e


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E


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At!ospheric Conditions

0) Su%1standard at!osphere 6J07

1 the !icro'a&e %ea! is %ent a'a" #ro! the

sur#ace o# the earth

1 produces a pheno!enon (no'n as Earthulging E##ectF

/) Standard at!osphere 6KB:=7

1 the !icro'a&e %ea! is slightl" %ent to'ards

the sur#ace o# the earth

1 nor!al at!ospheric condition


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=) Super1standard at!osphere 6LB:=7

1 the !icro'a&e %ea! is %ent to'ards the

sur#ace o# the earth

1 produces a pheno!enon (no'n as Eartho!ogenous at!osphere 6K07

1 no re#racti&e e##ect on the !icro'a&e signal

1 no densit" gradient


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) In#init" condition 6K7

1 the !icro'a&e %ea! tend to #ollo' the

cur&ature o# the earth

1 results to ero cur&ature or


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4ropagation Condition

Propagation Condition K factor

Perfect * temperat)re +one, no (o&, no

d)ctin&, &ood atmospheric condition day andni&ht

4/3

Ideal* dry, mo)ntaino)s, no (o& * ./0

Average * Flat, temperate, some (o& 1/0 *

Difficult* coastal 1/0 * 2

ad* coastal, water, tropical 2 - 1/3


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Earth ulge

1 change in &ertical height o# the earth9s sur#ace #ro! ahoriontal re#erence line 'ith respect to the distance)


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Earth ulge Co!putations

'here*

e%Kearth %ulge

d0Kdistance #ro! site 0

d/Kdistance #ro! site /

Ke##ecti&e earth9s radius#actor


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4ath Calculations

+ere3 d total di"tance in !idt radio orizon 5or tran"!it

antenna (!i)dr radio orizon 5or recei,eantenna (!i)t tran"!it antenna ei6t (5eet)r recei,e antenna ei6t (5eet)


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4ath Calculations

Terrestrial !icro'a&e lin(sgenerall" use line1o#1sightpropagation

The !ai!u! distance%et'een t'o stations depends

upon the height o# thetrans!itting and recei&ingantennas, as 'ell as theterrain %et'een the!

+ine1o#1sight propagation isde#ined %"*


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4o'er udget Calculations

a path po'er %udget is nothing %ut an ite!ied listo# all s"ste! losses and gains 6in deci%els7 #ro! thetrans!itter on one end o# the path to the recei&er onthe other end, and e&er"thing in %et'een)


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+in( udget

Trans!itter 4o'er

Trans!ission +ine +osses


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Transmission Losses

a) WAVE@UI5E +OSS1Ta(en #ro! the specs o# the'a&eguideused) This is the a!ount

o# loss, usuall" epressed in d per unit length 6d:#t or d:!7 o#signal as it tra&els in the 'a&eguide)

%) CONNECTOR +OSS1 ta(en #ro! specs6.) d7

c)COU4+IN@ +OSS1 ta(en #or! specs 6coato 'a&eguideto air7

d) >YRI5 +OSSD ta(en #ro! specs, AA circulator loss60d7

e) RA5OME +OSSD ta(en #ro! the specs6.) d7
http://var/www/apps/conversion/tmp/scratch_7/hyperlinks/waveguides.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/Microwave%20Connectors.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/coax.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/circulators.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/Radomes.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/Radomes.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/circulators.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/coax.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/Microwave%20Connectors.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/waveguides.ppt


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3. Atmospheric Absorption Loss (AAL)

a) O2Y@EN ASOR4TION +OSS

- attenuation due to the a%sorption o#

radio #re$uenc" energ" %"o"gen !olecules in the at!osphere)

%) WATER VA4OR +OSS

- attenuation due to the a%sorption o#radio #re$uenc" energ" %"'ater &apor in theat!osphere)
http://var/www/apps/conversion/tmp/scratch_7/hyperlinks/oxygen.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/water%20vapor.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/water%20vapor.ppthttp://var/www/apps/conversion/tmp/scratch_7/hyperlinks/oxygen.ppt


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4. Miscellaneous Path Loss (MPL)

a) 5I


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5. OTHER LOE

a) RAIN +OSSES

1 attenuation due to the e##ects o# rain

%) C+UTTER +OSSES

1 attenuation due to trees and %uildings inthe #ront o# the antenna


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c) ANTENNA MISA+I@NMENT

- hu!an #actor error) This loss co!es#ro! the condition o# the antenna 'hen %einginstalled) The &alue o# this loss is assu!ed ne&erto go a%o&e .)/d per antenna or .) d #or the

lin()


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4ara%olic Antenna @ain

English system:

5-#6 7.8 9 :;"o'f 5H< 9 :;"o'D f!

Metric system:

5-#6 =7.> 9 :;"o'f 5H< 9 :;"o'D m


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Net 4ath +oss

Recei&ed Signal +e&el

Eff i I i ""


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=. Effec!ive Iso!ropica""yRa-ia!e- +ower EIR+B

the a!ount o# po'er that 'ould ha&e to %e

e!itted %" an isotropic antenna to produce the

pea( po'er densit" o%ser&ed in the direction o#!ai!u! antenna gain)


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EIR4 K 4t @

antD T++

'here*

4tK R< po'er output 6d!7

@antK trans!it antenna gain 6d7

T++ K total trans!ission line loss at

trans!itter 6ta(en #ro! specs, in d7


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:. An!enna 5ain (orm*"a

@ant

K P 6Qd:7/

'here*

P D antenna e##icienc"

6t"pical &alue K .)7d K dia!eter o# antenna in !eters


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@ant

K /. log #6@>7

/. log d6!7

0)-

'here*

# K #re$uenc" in @>

d K dia!eter o# antenna in !eters


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3. Iso!ropic Receive Leve" IRLB

IR+ K EIR4 D


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8. Receive- Si'na" Leve" RSLB *nfa-e-

RS+ K IR+ @ant

D T++

RS+ K 4t @ant6T7D T++6T7D


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@. Receiver Treso"- C2NB

the !ini!u! 'ide%and carrier po'er 6C!in

7 at the

input to a recei&er that 'ill pro&ide a usa%le

%ase%and output; so!eti!es called recei&er

sensiti&it"

R i T "- C2NB


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Receiver Treso"- C2NB

C:N6d7

K RS+6d!7

1 4n6d!7

'here*4n K ther!al noise threshold o# the recei&ing

s"ste!

T " N i T "- + B


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7. Terma" Noise Treso"- +nB

4n K 0B 0. log N ( - M i (MB


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>. (a-e Mar'in (MB

e$uation considers the non1ideal and less

predicta%le characteristics o# radio 'a&e

propagation such as multi-path lossand terrainsensitivity

i i i


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Using arnett1Vignant E$uation*


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'here*


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A Values

B s!ooth terrain, o&er 'ater, or #lat desert

0 a&erage terrain

.)/ !ountains, &er" rough or &er" dr"terrain


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B Values

.) hot hu!id areas

.)/ a&erage inland areas, nor!al, interiorte!perature or su%1arctic areas

.)0/ !ountainous or &er" dr" %ut non1re#lecti&e areas

S t @ i


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S"ste! @ain

1It is the di##erence %et'een the no!inal outputpo'er o# a trans!itter and the !ini!u! inputpo'er re$uired %" a recei&er)

1It !ust %e greater than or e$ual to the su! o# allgains and losses incurred %" a signal as itpropagates #ro! a trans!itter to a recei&er)

1 It represents the net loss o# a radio s"ste!)


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@SK 4t1 C!in4

t1 C

!inL

+osses D @ains

'here*

@SD S"ste! @ain 6d7

4tD trans!itter output po'er 6d!7

C!in

D !ini!u! recei&er input po'er #or a

gi&en $ualit" o%8ecti&e 6d!7

@ K


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@SK


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Sa!ple 4ro%le!s

0)


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=) Consider a space1di&ersit" !icro'a&e radio s"ste!operating at an R< carrier #re$uenc" o# 0)- @>)

Each station has a /)B1!eter dia!eter para%olic

antenna that is #ed %" a 0..! o# air1#illed coaialca%le) The terrain is s!ooth and the area has a

hu!id cli!ate) The distance %et'een stations is B.

(!) A relia%ilit" o%8ecti&e o# )G is desired)

5eter!ine the s"ste! gain) The air1#illed coaial

ca%le has a #eeder loss o# )B d:0..! and

%ranching loss o# / d)


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RECEIVER SENSITIVITY

the !ini!u! 'ide%and carrier po'er o# the input o#the recie&er that 'ill pro&ide a usa%le %ase%andoutput)

Recei&er Ther!al Noise

1 so!eti!es called 5etection ThresholdF or

A%solute Noise ThresholdF

Pn = - 174 + 10 log

B + NF

I!pro&e!ent Threshold


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I!pro&e!ent Threshold

this is the point at 'hich the R< carrier1to noise ratiois e$ual to0. d

Carrier D to D Noise Ratio


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Carrier D to D Noise Ratio

The ratio o# the !ini!u! 'ide%and carrier po'er atthe input o# a recei&er that 'ill pro&ide a usa%le

%ase%and output to the 'ide%and noise po'erpresent at the input o# a recei&er and the noise

introduced 'ithin the recei&er)


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Ra"leigh 5istri%ution o#


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Sa!ple 4ro%le! 0

An ) The

trans!itter output po'er is =. d!) The recei&er9s

#ront end acti&e stage is a !ier 'ith a noise #igure o# d) The path length is /0 !i, the antennas at each

end ha&e a = d gain and the trans!ission line

losses at each end are = d) I# the


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Sa!ple 4ro%le! /

A !icro'a&e s"ste! operating at 3 @> uses atrans!itter 'ith an output po'er o# 0 W) oth sites

uses a 3 #t para%olic dish antenna 'ith a 'a&eguide

loss o# d per site) I# the distance %et'een the t'osites is =. !iles, deter!ine the relia%ilit" o# the

s"ste! using Ra"leigh 5istri%ution o#


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SYSTEM 4ER


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S"ste! Relia%ilit"

the percentage o# ti!e the s"ste! or lin( !eetsper#or!ance re$uire!ents

S"ste! Una&aila%ilit"


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S"ste! Una&aila%ilit"

4ath Relia%ilit"


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4ath Relia%ilit"

7t repre"ent" te percenta6e o5 ti!e telin8 i" e9pected to operate +itout anouta6e cau"ed /y propa6ation condition"

Sa!ple 4ro%le!s


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Sa!ple 4ro%le!s

0) I# the MT< o# a co!!unications circuit is /.,...hours and its MTTR is = hours, 'hat is its a&aila%ilit"

/) A long distance telephone co!pan" e!plo"s #i&e!icro'a&e radio hops o&er a single route to lin( t'oi!portant cities) I# each hop has an MT< o# 0.,...hours and an MTTR o# = hours, 'hat is the MTTR and

relia%ilit" o# the route Assu!e that the #ailure occurat di##erent periods o# ti!e)

microwave communication system

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