Krisna DSK Udayana 05-TransmissionMedia

8/10/2019 Krisna DSK Udayana 05-TransmissionMedia

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Transmissionistheprocessoftransportinginformationbetweenend ointsofas stemornetwork.

Transmissionsystems

may

use

copper

cable,

optical

cable,

or

radiochannelstointerconnectfarendandnearend.

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TransmissionMedia

Guided

Cable

Medium

more

important

than

the

signal Ungui e

Atmosphere

OuterSpace

Signalmoreimportantthanthemedium

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Twoinsulatedcopperwiresinaspiral

Twistingdecreases

crosstalk

Mostcommonformforanalo anddi ital

Usedintelephonesystem

Subscriberloops

Fromapersonshometothelocalofficeofthephone

company

10Mbpswithnewerat100Mbps

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LongDistance 4 Mb s

ISDN Integrated

Services

Digital

Network

Digital Repeatersrequiredevery23kilometers

Analog Bandwidthof250KHz,carryafewvoicechannels

Susceptibletonoise,shielded (STP)andunshielded

. Comparedtoopticalandcoaxtwistedpairislimited

inbandwidth distance anddatarate

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ara e nes are o en use as

part of antenna arrays. Ordinary

television twinlead, is an example

Figure (a).

Parallel lines can be shielded to

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,

illustrated

in Figure (b).


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Hollowoutercylindricalconductor

surroundingasingle

view

Mostversatileofmediums usedforTV lon

distancetelephone,andLANS

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Partoflongdistancetelephonenetwork

,

Transmitsboth

analog

and

digital

signals

Fre uenc characteristicssu eriortotwisted air

Lesssusceptibletonoise

Forlong

distance

Amplifiersneededeveryfewkilometers

Repeatersneededeverykilometerorso

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Coaxial Cable Applications

For coaxial cable, the characteristic

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,

glassor

plastic

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Betterthancoaxialcableortwistedpair

Dataratesof2Gb sover10sofKm

Lightweight

good

for

buildings

Lowerattenuationthancoaxortwisted

o e ec e yex remee ec romagne c e s

Crosstalkandimpulse

Verydifficult

to

tap

good

security

Applications

LongHaultrunks,metrotrunks,ruralexchangetrunks,more

loopsand

in

LANS

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Operatesinrange1014 to1015 Hz

Multimode Varietyofanglesoflightwillreflectandpropagate

SingleMode

Radiusofthecore=orderofawavelength

Superiorperformance

Twodifferentlightsources bothemitlightwhenvoltageapplied

LED Light

Emitting

Diode

less

costly,

longer

life

ILDInjectionLaserDiode greaterdatarate

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Antennae

FocusedEM

beam

Thehigherfrequencythemorefocused

Omnidirectional

Lowerfrequency

Threerangesoffrequencies

26GHz 40GHzmicrowave

30MHz

1GHz

broadcast

radio

3x10**11to2x10**14Hzinfrared

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TerrestrialMicrowave

ara o c

s

Narrowbeam lineofsightontowerstoavoidobstacles

Seriesoftowersforlongdistance

Applications:

VoiceandTV

Shortpoint

to

point

between

buildings

MainSourceofloss

Attentuation especiallywithrainful

Re eaters or am lifiers 10 to 100km

Interferencewith

overlapping

bands

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SatelliteMicrowave

Itisessentiallyamicrowaverelaystation

Receivestransmission

on

one

frequency

Transmitsonasecondfrequency

Operateson

anumber

of

frequency

PointtoPoint

Groundstationtosatelliteto

Multipoint

Groundstationtosatellitetomu p erece v ngs a ons

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SatelliteMicrowave Satelliteorbit

35,784Km,tomatchearthrotation

ays xe a ove e

transmitter/receiverstation

as

earthrotates

Satellitesneedtobeseparatedby

distance

Avoidinterference

Applications

, ,Optimum frequency range 1 10 GHz

Below 1GHz results in noise, above 10GHz results in severe

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Omnidirectionalunlikesatellite

Frequencyrange

Radio3kHzto300Ghz

Broadcastradio 30MHzto1GHz

Broadcastradio

Transmissionlimitedtolineofsight

Lesssensitivetoattenuationfromrainfallthanmicrowave

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eachother

or

via

reflection

No

frequency

allocation

or

licensing

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Documents

Krisna DSK Udayana 05-TransmissionMedia