数字调制解调技术大学毕业论文英文文献翻译及原文Word文档格式.docx

数字调制解调技术大学毕业论文英文文献翻译及原文Word文档格式.docx

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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 

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 

errorparameterbasedonIQgainimbalanceandphaseimbalance.4）.Themetrologymethodandsystemfordigital 

errorparameterbasedonanalogPMintheaspectofGMSKandFSK 

modulation.5）.Themetrologymethodandsystemfordigital 

errorparameterbasedonBasebandwaveformdesign.Basedonthesemethods,ourproposalaregivenasfollows:

first,establishpublicmetrologystandardfordigital 

errorparameters;

second,developanewtypeofinstrument"

vectorsignalanalyzercalibrator"

.

Inthispaper,weproposeanovelmethodofchaotic 

basedonthecombinationofChaoticPulsePosition 

Modulation 

（CPPM）andChaoticPulseWidthModulation 

（CPWM）.Thiscombinationlooksverypromisingfortheimprovementofinformationprivacyinchaos-baseddigitalcommunications.IntheCPPM+CPWMmethod,eachpulseisachaoticsymbolwhichcarriesbinaryinformationoftwobitscorrespondingtoitspositionandwidth,wherethepositionisdeterminedbytheintervalbetweenrisingedgeofthecurrentpulsecomparedtothepreviousoneandthewidthisdeterminedbythedurationbetweentherisingedgeandthefallingedgeofthesamepulse.Thisofferstheincreaseofbitrate,bandwidthefficiencyandprivacyincomparisonwiththemethodofCPPM.Theschemesof 

andDemodulation 

（MoDem）ofCPPM+CPWMareproposed,designedandanalyzedthatbasedontheconventionalschemesofCPPM.ThenumericalsimulationintimedomainofthesystemofCPPM+CPWMMoDemisimplementedinMatlab/Simulink.

Itgivesasummaryoftheoreticalandpracticalstudiesonthepropertiesofpulse-phase 

modulation,developedmainlyin1943.Thepropertiesofpulse-phasemodulation 

arestudiedbymeansofFouriertransformations.Althoughsomeapproximationsareintroduced,thecalculationsleadtothefollowingdefiniteconclusions:

（1）Pulse-phase 

introducesnoamplitudedistortionexceptatsub-multiplesoftherecurrentfrequency.

（2）Theharmonicdistortion,ifany,isnegligibleandthismethodof 

canbeusedforhigh-qualitybroadcasting.（3）Pulse-phase 

issubjecttoaspecialtypeofdistortioncalled?

cross-distortion,?

producedbysidebandsoftherecurrentfrequencyappearinginthesignalbandwidth.Curvesoftheapproximateamountofthistypeofdistortionaregiven,anditisshownthat,inpracticalmulti-channelsystems,thisdistortionisnegligible,providedthattherecurrentpulsefrequencyisatleastdoublethehighestsignalfrequencytobetransmitted,andpreferablyequalto,orgreaterthan,threetimesthisfrequency.Thisstudyisfollowedbyconsiderationsonthesignal/noiseratioinpulse-phase 

modulation.Pulse-phasemodulation 

iscomparedwithamplitude 

andaformula,givingtheimprovementinthesignal/noiseratioduetopulse-phase 

modulation,isestablishedbyverysimpleconsiderations.Itisshownthatthisratioimprovesasthefrequencybandwidthusedinpulse-phase 

modulation.Itisshownhowanimprovementof3dbinsignal/noiseratiocanbeobtainedbysuppressingthenoiseonthesynchronizingpulse,andapracticalcircuitdevelopedandappliedin1943bytheauthorisdescribed.Finally,atypicalexampleofpulsetechniqueisgiven.Inpracticalcircuitsthemodulatoranddemodulatorpulsesarenotperfectlyshaped,becauseofthedeparturefromlinearityduetofinitetime-constants.Thisintroducesharmonicdistortion.Itisshownhowthisdistortioncanbepracticallyelimi-natedbydesigningcircuitssothatthetimeconstantisequalat 

modulationand 

demodulation.

Itpresentanoveltechniquefordigitaldata 

and 

demodulationcalledtriangular 

（TM）.The 

techniquewasdevelopedprimarilytomaximizetheamountofdatasentoveralimitedbandwidthchannelwhilestillmaintainingverygoodnoiserejectionandsignaldistortionperformance.Themodulation 

techniqueinvolvesbreakingdigitaldataintoaseriesofparallelwords.Eachwordisthenrepresentedbyonehalfperiodofatriangularwaveformwhoseslopeisproportionaltothevalueoftheparallelworditrepresents.Thedemodulation 

techniqueforthisuniquelydefinedwaveforminvolvesfirstdigitizingthewaveformatahigherconstantsamplingrate.Alinearregressionalgorithmusingthemethodofleastsquaresisthenusedtocomputetheslopeofthedigitizedwaveformtoaveryhighprecision.Thisprocessisrepeatedforeachrisingandfallingedgeofthetriangularmodulatedwaveform.Allencodeddataisextractedbypreciseslopecomputationsinceeachslopeuniquelydefinestheencodeddataworditrepresents.Theabilityofthe 

algorithmtocomputetheexactslopeofthemodulatedwaveformdetermineshowmanybitscanberepresentedbythemodulatedwaveform.Transmissionchannelbandwidthlimitationsdeterminetheallowablerangeofslopesused.Severalsimulationsareperformedtoprovideasampleofhowthe 

methodwillperforminvariousrealworldenvironments.Thepaperalsodiscussesseveralapplicationareaswherethemodulation 

techniquewillprovidesuperiorresultsoverother 

methods.

Thetheoryofconstantenvelopeorthogonalfrequencydivisionmultiplexing（CE-OFDM）isanalyzedinthispaper,alongwiththeintroductionoftheimplementationmethodofCE-OFDMtechnique.Besides,the 

processissimulatedandanalyzed.AndtheresultsindicatethatCE-OFDMconductsphasemodulation 

onthebasisofOFDM 

modulation.Thus,FFT/IFFTisimplementedinthetransmittingandreceivingterminals.Furthermore,themethodofequalizationappliedinthe 

processcanoptimizesystemperformance.Andalso,CE-OFDMsolvestheproblemofhighpeak-to-averagepowerratio（PAPR）inOFDM,reducingPAPRto0Db.

Highefficient 

technologyisahotresearchtopic.UNB 

modulation,foritsgoodperformance,ispaidtomoreattention.First,thearticleintroducesEBPSK 

schemeasUNB 

method,givesitstimeandfrequencydomaincharacteristicsandpres