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1、QPSKSystemDesignandSimulation:LaboratoryManualHours:4SCIE,UESTCOutlineObjectivesTheoriesCarriersynchronizationSymbolsynchronizationExperimentsObjectivesGeneratingQPSKmodulatedsignals,includinggenerationofinformationsource,matchedfilterdesignandmodulationopera
2、tions;Retrievingsignalstransmittedoverwirelesspropagationchannels,i.e.,modulatedsignalsatreceiver.Notethatthetransmitterandreceiveraremutualindependent.Further,frequencyoffsetmayoccurinreceivedsignals,therefore,carrierandsymbolsynchronizationarerequired.Objec
3、tives(Con’t)Understandingthetheoriesonoptimalreceiverstructure,correlateddetectionandmatchedfiltering;DesigninganoptimalreceiverforQPSKmodulatedsignals.TheoriesQPSKReceiverDiagramTheoriesCarrierSynchronizationEnormousalgorithmsforcarriersynchronization,PLL,na
4、rrowbandfiltering,etc.Weutilizeadigitalsignalprocessingmethodtodirectlyestimatethefrequencyoffsetusedlattertocompensatethecarrierfrequencyoffset.Assuminginthisexperiment,thefrequencyoffsetbetweentransmitterandreceiveriswithin50kHz,orlessthan1/1000ofthesymbolr
5、ate.TheoriesSymbolSynchronizationTheoriesSymbolSynchronization(Con’t)Differentsymbolsynchronizationtechniquesonlydifferinthetimingrecoveryalgorithmsandtheloopfilterdesign.Thefunctionofloopfilter,sotermedassmoothingfilter,istoeliminatenoise.Variousmethods,such
6、as,Godneralgorithm,maximaloutputpoweralgorithm,etc.Themaximaloutputpoweralgorithm,whichisarefinementofgradientdescent,isutilizedinthisexperiment.ExperimentsWritematlabprogramtoSimulateQPSKsignalmodulation,andgenerateQPSKmodulatedsignalsDemodulateQPSKsignalsDi
7、rectlydemodulateQPSKsignalswithoutcarrierorsymbolsynchronization,andobservetheoutputsignalconstellation.Addcarriersynchronizationandsymbolsynchronizationatthereceiver,andobservethecorrespondingoutputsignalconstellation.Selectdifferentalgorithmsforcarriersynch
8、ronizationandsymbolsynchronization,andobservetheconstellationAnalysisandreportsExperiments(Con’t)Youareexpectedtocompleteindividuallyandindependently.Yourworkmustbeoriginalandthelabreport
