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.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
文献、资料中文题目:
数字调制解调技术
文献、资料英文题目:
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翻译日期:
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,givesitstimeandfrequencydomaincharacteristicsandpres
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