数字调制解调技术大学毕业论文英文文献翻译及原文.docx

数字调制解调技术大学毕业论文英文文献翻译及原文.docx

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数字调制解调技术大学毕业论文英文文献翻译及原文

毕业设计（论文）

外文文献翻译

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数字调制解调技术

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2017.02.14

英文文献

Technologyofdigitalmodulationanddemodulationplaysaimportantroleindigitalcommunicationsystem,thecombinationofdigitalcommunicationtechnologyandFPGAisacertainlytrend.Withthedevelopmentofsoftwareradio,therequirementfortechnologyofmodulationanddemodulationishigherandhigher.Thispaperstartswithstudyingdigitalmodulationanddemodulationtheoryatfirst,andanalysesbasicprincipleofthreekindsofimportantmodulationanddemodulationway（FSK,MSK,GMSK）.TheRohde&SchwarzSME03,SignalGenerator,providesAMmodulationandExternalFSKdigitalmodulationrequiredforthedevelopmentandtestingofdigitalmobileradioreceivers.TheapplicationofPWMindigitalmodulationanddemodulationforanalogcommunicationsignalsinseveralmodulationmodesResearchresultsprovethatthedesignofdigitalIFmodulatoranddemodulatorofSoftwareRadioappeasesthecapabilityandrequirementofSoftwareRadio.Atransfusionspeedmonitorsystemisdesignedbasedoninfraredtechnologywithmodulationanddemodulation.It'sthecombinationofmodulatoranddemodulator.Timesynchronizationthatiskeytechnologyofdigitaldemodulationisccalliedbysoftware.ThepaperprovidesthedesignofhardwareofdigitalIFmodulatoranddemodulatorofSoftwareRadiowhichincludesDigitalSignalProcessor、MicroControlUnitandAD/DAconvertoretc.DigitalDown/UpConverter（DDC/DUC）,modulationanddemodulationarediscussedinthedissertationassomeessencialpartsofSDRplatform.TwoWayAutomaticCommunicationSystem（TWACS）isanewvaluablecommunicationtechnologyfordistributionnetworks,whichhasspecialofmodulationanddemodulation.Inthispaper,westudytheOFDMtechnologybasedon802.16a,realizethebasebandmodulationanddemodulationbyusingTMS320C6201,andoptimizethesoftwaremodule.ThepaperintroducestheprincipleofQPSKmodulationanddemodulation,thecircuitarealsoberealizedbasedonFPGA.Withtheimprovementofthetechnology,especiallyinthefieldssuchascomputertechnology,datacodingandcompress,digitalmodulationandVLSI,theworldelectronicinformationindustryenterintothedigitalera.First,thefeaturesoffaxcommunicationandthemodeofmodulationanddemodulationaredescribed.Inautomaticclassificationofdigitalmodulationsignal,computingenvelopevarianceafterdifferencehasimportantmeaningtodistinguishPSKandFSKsignal.Thescienceandtechnologyofspaceflight.TheeffectonmodulationanddemodulationofQPSKviacarrierphasenoisecannotbeignored,anditisdifficulttoanalyze.

Digital modulation errorparameters,suchaserrorvectormagnitudeEVM,isimportantintestandmeasurementofinformationsystem.Thispaperintroducesthetechnologyresearchprogressinthemetrologyofdigital modulation errorparameters.First,wepointoutthebasicproblemsexistinginthefield,whichisabouttraceabilityandparameterrangeofcalibration,anddescribetherelevantresearch,suchasthethinkingandtechnologyofthe`RFwaveformmetrology'.Then,wehighlighttheresearchprogressofourteam:

1）.Themetrologymethodandsystemfordigital demodulation errorparameterbasedonCWcombination,whichfitsBPSK,QPSK,8PSK,16QAM,64QAM modulation:

thismethodcanachievetraceabilityanderrorsettingabilityinawiderange,whenstandardEvmRmsis1.585%,theexpandeduncertainty（k=2）is0.009%.2）.Themetrologymethodandsystemfordigitaldemodulation errorparameterbasedonanalog AM orPM.3）.Themetrologymethodandsystemfordigital demodulation errorparameterbasedonIQgainimbalanceandphaseimbalance.4）.Themetrologymethodandsystemfordigital demodulation errorparameterbasedonanalogPMintheaspectofGMSKandFSK modulation.5）.Themetrologymethodandsystemfordigital demodulation errorparameterbasedonBasebandwaveformdesign.Basedonthesemethods,ourproposalaregivenasfollows:

first,establishpublicmetrologystandardfordigital modulation errorparameters;second,developanewtypeofinstrument"vectorsignalanalyzercalibrator".

Inthispaper,weproposeanovelmethodofchaotic modulation basedonthecombinationofChaoticPulsePosition Modulation （CPPM）andChaoticPulseWidthModulation （CPWM）.Thiscombinationlooksverypromisingfortheimprovementofinformationprivacyinchaos-baseddigitalcommunications.IntheCPPM+CPWMmethod,eachpulseisachaoticsymbolwhichcarriesbinaryinformationoftwobitscorrespondingtoitspositionandwidth,wherethepositionisdeterminedbytheintervalbetweenrisingedgeofthecurrentpulsecomparedtothepreviousoneandthewidthisdeterminedbythedurationbetweentherisingedgeandthefallingedgeofthesamepulse.Thisofferstheincreaseofbitrate,bandwidthefficiencyandprivacyincomparisonwiththemethodofCPPM.Theschemesof Modulation andDemodulation （MoDem）ofCPPM+CPWMareproposed,designedandanalyzedthatbasedontheconventionalschemesofCPPM.ThenumericalsimulationintimedomainofthesystemofCPPM+CPWMMoDemisimplementedinMatlab/Simulink.

Itgivesasummaryoftheoreticalandpracticalstudiesonthepropertiesofpulse-phase modulation,developedmainlyin1943.Thepropertiesofpulse-phasemodulation arestudiedbymeansofFouriertransformations.Althoughsomeapproximationsareintroduced,thecalculationsleadtothefollowingdefiniteconclusions:

（1）Pulse-phase modulation introducesnoamplitudedistortionexceptatsub-multiplesoftherecurrentfrequency.

（2）Theharmonicdistortion,ifany,isnegligibleandthismethodof modulation canbeusedforhigh-qualitybroadcasting.（3）Pulse-phase modulation issubjecttoaspecialtypeofdistortioncalled?

cross-distortion,?

producedbysidebandsoftherecurrentfrequencyappearinginthesignalbandwidth.Curvesoftheapproximateamountofthistypeofdistortionaregiven,anditisshownthat,inpracticalmulti-channelsystems,thisdistortionisnegligible,providedthattherecurrentpulsefrequencyisatleastdoublethehighestsignalfrequencytobetransmitted,andpreferablyequalto,orgreaterthan,threetimesthisfrequency.Thisstudyisfollowedbyconsiderationsonthesignal/noiseratioinpulse-phase modulation.Pulse-phasemodulation iscomparedwithamplitude modulation andaformula,givingtheimprovementinthesignal/noiseratioduetopulse-phase modulation,isestablishedbyverysimpleconsiderations.Itisshownthatthisratioimprovesasthefrequencybandwidthusedinpulse-phase modulation.Itisshownhowanimprovementof3dbinsignal/noiseratiocanbeobtainedbysuppressingthenoiseonthesynchronizingpulse,andapracticalcircuitdevelopedandappliedin1943bytheauthorisdescribed.Finally,atypicalexampleofpulsetechniqueisgiven.Inpracticalcircuitsthemodulatoranddemodulatorpulsesarenotperfectlyshaped,becauseofthedeparturefromlinearityduetofinitetime-constants.Thisintroducesharmonicdistortion.Itisshownhowthisdistortioncanbepracticallyelimi-natedbydesigningcircuitssothatthetimeconstantisequalat modulationand demodulation.

Itpresentanoveltechniquefordigitaldata modulation and demodulationcalledtriangular modulation （TM）.The modulation techniquewasdevelopedprimarilytomaximizetheamountofdatasentoveralimitedbandwidthchannelwhilestillmaintainingverygoodnoiserejectionandsignaldistortionperformance.Themodulation techniqueinvolvesbreakingdigitaldataintoaseriesofparallelwords.Eachwordisthenrepresentedbyonehalfperiodofatriangularwaveformwhoseslopeisproportionaltothevalueoftheparallelworditrepresents.Thedemodulation techniqueforthisuniquelydefinedwaveforminvolvesfirstdigitizingthewaveformatahigherconstantsamplingrate.Alinearregressionalgorithmusingthemethodofleastsquaresisthenusedtocomputetheslopeofthedigitizedwaveformtoaveryhighprecision.Thisprocessisrepeatedforeachrisingandfallingedgeofthetriangularmodulatedwaveform.Allencodeddataisextractedbypreciseslopecomputationsinceeachslopeuniquelydefinestheencodeddataworditrepresents.Theabilityofthe demodulation algorithmtocomputetheexactslopeofthemodulatedwaveformdetermineshowmanybitscanberepresentedbythemodulatedwaveform.Transmissionchannelbandwidthlimitationsdeterminetheallowablerangeofslopesused.Severalsimulationsareperformedtoprovideasampleofhowthe modulation methodwillperforminvariousrealworldenvironments.Thepaperalsodiscussesseveralapplicationareaswherethemodulation techniquewillprovidesuperiorresultsoverother modulation methods.

Thetheoryofconstantenvelopeorthogonalfrequencydivisionmultiplexing（CE-OFDM）isanalyzedinthispaper,alongwiththeintroductionoftheimplementationmethodofCE-OFDMtechnique.Besides,the modulation and demodulation processissimulatedandanalyzed.AndtheresultsindicatethatCE-OFDMconductsphasemodulation onthebasisofOFDM modulation.Thus,FFT/IFFTisimplementedinthetransmittingandreceivingterminals.Furthermore,themethodofequalizationappliedinthe demodulation processcanoptimizesystemperformance.Andalso,CE-OFDMsolvestheproblemofhighpeak-to-averagepowerratio（PAPR）inOFDM,reducingPAPRto0Db.

Highefficient modulation technologyisahotresearchtopic.UNB modulation,foritsgoodperformance,ispaidtomoreattention.First,thearticleintroducesEBPSK modulation schemeasUNB modulation method,givesitstimeandfrequencydomainch