telcommunications final project report电子毕业设计报告.docx

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telcommunicationsfinalprojectreport电子毕业设计报告

AnalysisofTelecommunicationSystems

GuoQi

X00097450

BachelorofelectronicEngineering（ORD）

April2015

Supervisinglecturer:

MrDonalO’Toole

HeadofDepartment:

MrJamesWright

DELARATION

Ideclarethatthisreportismyownworkandthatallcontributionsfromotherpeopleandsourcesarereferencedinthebodyofthereportandfullylistedinthereferencessectionattheendofthereport.Iacceptthatpresentingotherpeople’sworkasmyownisaseriousoffenceanditisalsoaseriousbreachoftheInstitute’sregulations.

Studentname:

GuoQiDate:

04/2015

ABSTRACT

TheaimofthisprojectistouseSIMULINKinMATLABtoinvestigatethebehaviorofarangeofTelecommunicationSystems.StudentsareencouragedtoworktogetherinthefirstsemestertolearnhowtouseandapplyvariousSimulinkblockstoconstructandexaminedifferentTelecommunicationSystems,forexamplePSDsforsignalsandnoise,noisegeneration,basebandsignal,eyediagramsandpassbandsignals.InthesecondsemesterareexpectedtoconstructandanalyzevariousTelecommunicationSystemswithindividuallyassignedspecificationssuchasclockrecovery,channelcodesandsoon.

GLOSSARYOFTECHNICALTERMINOLOGY

PSD（PowerSpectralDensity）:

PowerSpectralDensitydescribesthepowerperunitareaperunitwavelengthofanillumination.*[1]

PDF（ProbabilityDensityFunction）:

isafunctionthatdescribestherelativelikelihoodforthisrandomvariabletotakeonagivenvalue.*[2]

Gaussiannoise:

isstatisticalnoisehavingaprobabilitydensityfunction（PDF）equaltothatofthenormaldistribution,whichisalsoknownastheGaussiandistribution.*[3]

ISI（IntersymbolInterference）:

isaformofdistortionofasignalinwhichonesymbolinterfereswithsubsequentsymbols.*[4]

AWGN（AdditiveWhiteGaussianNoise）:

isabasicnoisemodelusedinInformationtheorytomimictheeffectofmanyrandomprocessesthatoccurinnature.*[5]

BER（BitErrorRate）:

isthenumberofbiterrorsperunittime.*[6]

Jitter:

isthedeviationfromtrueperiodicityofapresumedperiodicsignalinelectronicsandtelecommunications,ofteninrelationtoareferenceclocksource.*[7]

NRZ（Non-Return-To-Zero）:

anon-return-to-zero（NRZ）linecodeisabinarycodeinwhich1sarerepresentedusuallybyapositivevoltageand0sarerepresentedusuallybyanegativevoltage,withnootherneutralorrestcondition.*[8]

SNR（Signal-to-noiseratio）isameasureusedinscienceandengineeringthatcomparesthelevelofadesiredsignaltothelevelofbackgroundnoise.*[9]

LPF（low-passfilter）isafilterthatpassessignalswithafrequencylowerthanacertaincutofffrequencyandattenuatessignalswithfrequencieshigherthanthecutofffrequency.*[10]

CHAPTER1:

INTRODUCTION

1.1BACKGROUND

Telecommunicationistouseelectricalsignalsorelectromagneticwavestocommunicateatadistancebytechnologicalmeans.Thewordisoftenusedinitspluralform,telecommunications,becauseitinvolvesmanydifferenttechnologies.

Intelecommunication,acommunicationssystemisacollectionofindividualcommunicationsnetworks,transmissionsystems,relaystations,tributarystations,anddataterminalequipment（DTE）usuallycapableofinterconnectionandinteroperationtoformanintegratedwhole.Thecomponentsofacommunicationssystemserveacommonpurpose,aretechnicallycompatible,usecommonprocedures,respondtocontrols,andoperateinunion.Telecommunicationsisamethodofcommunication（e.g.,forsportsbroadcasting,massmedia,journalism,etc.）.Acommunicationssubsystemisafunctionalunitoroperationalassemblythatissmallerthanthelargerassemblyunderconsideration.*[11]

1.2OBJECTIVES

1.Measurementandcalculatesignalandnoisepowerspectraldensities.

2.Generate,transmitanddetectsignalsusingM-arysignalling（AlluseM=4）.Useandoptimalreceiver.

3.Usethefollowingchannels:

1）NoisyChannelonly

（2）NoisyandDispersiveChannel.

4.UseBERdetectortodetermineerrors.Presentresultsinasuitabletable.

5.UseM-QAMasanexampleofpassbandmodulation.Provideconstellationplots.

6.PrepareComparisonStudies:

（a）Usingnoisychannelonly:

CompareperformanceofassignedlinecodewithM-aryQAM.

（b）Usingnoisyanddispersivechannel:

Compareperformanceofassignedlinecodetothatofasystemusingraisedcosinepulse.

7.Analysisisincludedwherepossible.UseSimulinkblockstodeterminenoisepowerandsignalpower.UseequationstodetermineerrorprobabilityandcomparetotheBERfromthesimulation.

8.Useeyediagramstoillustratetheeffectoftimingjitter,channelnoiseandchanneldispersion.

9.ImplementSynchronization（ofassignedBasebandsystem）

10.Implementchannelcode（cycliccode）

CHAPTER2:

LITERATUREREVIEW

DigitalCommunicationSystemsUsingMATLABandSimulink,DennisSilage,2009

2.1INTRODUCTION

TheaimofthischapteristointroducethedifferentkindsofblocksinSimulinkwewilluseinMATLABlater.

2.1.1.RandomIntegerGenerator

TheRandomIntegerGeneratorblockisthedatasourcefromtheCommSources,CommunicationsBlocksetwhichproducesrandombinaryintegers（0and1）atadataraterb=1.6kbits/secwhichisgivenasanexampleshowninFigure2.1.1,sothedatabittimecanbecalculatedTb=1/rb=6.25x10-4sec.

Figure2.1.1RandomIntegerGenerator

2.1.2Ratetransition

TheRateTransitionblockfromtheSignalAttributes,SimulinkBlocksetproducesdataatasimulationsampletimeTsimulation=1.25x10-5secwhichisgivenasanexampleshowninFigure2.1.2.Becausethesesignalsaresampledatan80kHZsimulationratewithTb=6.25x10-4sec,eachsignalhas50simulationsamplesperbittimeTb（Wehavealreadyknownrb=1.6kbits/secwhichisgivenasanexample）.

ThedataistransferredbyRateTransitionblockfromtheoutputofablockwithoneratetotheinputofablockwithadifferentrate.

Figure2.1.2ratetransition

2.1.3Sum,offsetandGainblock

Theunipolarbinarydata（0and1）isoffsetby-0.5（thisvalueisjustanexample）whichisshowninFigure2.1.3,withtheConstantblockandtheSumblock,andprocessedbytheGainblockfromtheSourceandMathOperations,SimulinkBlocksetwithaparameterofagainG=10（thisvalueisjustanexample）togeneratesignal.Theseblockstransmit100%dutycycle,polarrectangularpulsesandaretheinitialprototypeforPAM.

Figure2.1.3Sum,offsetandGainblock

2.1.4AWGNChannel

AWGN（AdditiveWhiteGaussianNoise）representsthechannelbytheblockfromtheChannels,CommunicationsBlocksetwhichisshowninFigure2.1.4,withtheparameterofvariance

2=5（thisvalueisjustanexample）andmean=0.

Figure2.1.4AWGNChannel

2.1.5SampleandHold

ThesimplePAMreceivershowninFigure2.1.5istheSampleandHoldblockfromtheSignalOperations,SignalProcessingblockset,withtheparameterofarisingedgecontrolsignal.

Figure2.1.5SampleandHoldblock

2.1.6PulseGenerator

APulseGeneratorblockfromtheSources,SimulinkBlocksetisshowninFigure2.1.6,withparametersofaunipolaramplitudeA=0Vor1V,bittimeTb=6.25x10-4sec（thisvalueisjustanexample）,apulsewidthof10%Tb=6.25x10-5secandaphasedelayofTb/2=3.125x10-4sec.

Figure2.1.6PulseGenerator

2.1.7Sign

ThedataisinputtedtotheSignblockfromtheMathOperations,SimulinkBlockset,showninFigure2.1.7,whichproducesa1iftheinputislargerthanzero,zeroiftheinputiszeroand-1iftheinputissmallerthanzero.

Figure2.1.7Signblock

2.1.8LookupTable

Theoutput（-1,0,1）ischangedtobinary（-5,5）bytheLookupTableblockfromtheLookupTables,SimulinkBlocksetwhichisshowninFigure2.1.8,withinputvaluesof[-1,0,1]andoutputdataof[-5,-5,5].

Figure2.1.8LookupTable

2.1.9Scopeblock

TheScopeblockfromtheSinks,SimulinkBlocksetisabletodisplaythedatasource,whichisshowninFigure2.1.9.

Figure2.1.9Scope

2.1.10BERcalculationblock

TheErrorRateCalculationblockforbiterrorrate（BER）analysis,showninFigure2.1.10,derivedfromtheCommSinks,CommunicationsBlockset.Parametersaresetwithareceiveddatadelayof1（thisvalueofdelaydependsonyourcircuit）tocompensateforthesimplePAMreceiver.

Figure2.1.10BERcalculationblock

2.1.11LowpassFilter

Figure2.1.11showstheparametersofanAnalogFilterDesignblock.Thisblockprovidesalowpassfilter（LPF）,whichisselectedtobea9-poleChebyshevtypeIfilter.Also,wecangetitscutofffrequency

=1.2kHz（1.2xrb,rb=1kHZisjustanexample）andanpassbandrippleof0.1dB（≈1%ripple）.TheparametersoftheAnalogFilterDesignblockneedapassbandedgefrequencyinradians/secor2

=2

（1200）rad/sec.

Figure2.1.11LowpassFilter

2.1.12Eyediagramblock

TheEyediagramblockshowninFigure2.1.12derivesfromtheCommSinks,CommunicationsBlockset,whichisabletodisplayarepeatingtimeslice,centeredat1msec,withalengthof2msec.

Figure2.1.12Eyediagram

2.1.13VariableTimeDelayblock

TheVariableTimeDelayblockderivesfromtheContinuous,SimulinkBlockset,whichisshowninFigure2.1.13.TheVariableTimeDelayblockaddstheoutputofthepreviousgeneratorblockasanotherinputwithamaximumdelayof2.5msec（thisvalueisanexample）.

Figure2.1.13VariableTimeDelayblock

2.1.14UniformRandomNumberblock

TheuniformRandomNumberblockshowninFigure2.1.14derivesfromtheSources,SimulinkBlockset,withauniformdistributedpdfofamplitudesfromaminimumvalue2x10-5（thisvalueisanexample）toamaximumnumber5x10-4（thisvalueisalso