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1、贵州大学硕士学位论文ABSTRACTPurposeofcommunicationsignalsmodulationrecognitionistojudgethemodulationmethodfromasectionofinterceptedsignalsunderthelesspriorinformation.Withthefastdevelopmentofcommunicationtechnique,thestylesofcommunicationsignalsbecomemorecomplexandvarious.Signalenvironmentisgraduallyintensi
2、ve,thismakessignalrecognitionmoredifficult.Howtocarryoutthefeatureparameterextractionandmodulationrecognitionundertheconditionofthelowsignalnoiseratio(SNR)?Thisisthemaincontentofthethesis.Becausewavelettransformhasmulti-resolutionanalysisfeature,wecancarryouttheparameterextraction(symbolrate)ontyp
3、icalanaloguesignalsanddigitalsignalsbytwicecontinuouswavelettransformandonetimeFouriertransform.Moreover,theanaloguesignalscanbedistinguishedfromdigitalsignalsbytheextractedparameter.ThecombinationofHilberttransformanddiscretewavelettransformisusedtoextractinstantaneousamplitude,frequencyandphasef
4、romthesixdigitalsignalswhichare2ASK,4ASK,2FSK,4FSK,2PSK,4PSK,andthen,wecandothemodulationrecognitionfurtherly.Weextractphaseinformationfrom2PSK,4PSKand8PSKbycontinuouswavelettransform,meanwhile,wecarryoutmodulationrecognitionforin-classMPSKthroughthewaveletcoefficientpeakcollectionprobabilitydensi
5、tyfunctionandmaximumlikelihoodfunction.Foranaloguemodulationsignalswhicharethebasisofdigitalmodulationsignals,traditionaldecisiontheoryisusedtodomodulationrecognitionforthefivetypicalanaloguesignals(AM,DSB,FM,PM,SSB).Thedecisiontheoryisalsousedtodomodulationrecognitionforthesixdigitalsignalsmentio
6、nedabove.Furthermore,wecomparetheeffectofdecisiontheorywiththatofwavelettransform.Finally,thetraditionaldecisiontheoryisimprovedfromtheaspectoftheparameterextraction.Thetypesofrecognitionareextendedto8PSKand16QAMthroughtheimprovedmethod,moreover,thecorrectrecognitionrateandtherangeofSNRarealsobeim
7、provedhighly.Keywords:Communicationsignals,Wavelettransform,Featureextraction,Modulationidentification,DecisiontheoryII贵州大学硕士学位论文第1章绪论1.1研究背景通信信号调制识别的基本任务是在多信号环境和有噪声干扰的条件下确定出接收信号的调制方式及其一些信号参数，从而为进一步分析和处理信号提供依据。随着
