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TN912.3101832200630StudyandImplementationofSpeechEnhancementAlgorithm20011220032VADKLKLKLVAD(VoiceActivityDetection)KLMATLABTIDSKKLDSKAbstractTheaimofspeechenhancementistocompressbackgroundnoise,toextractpurespeech,andtoimprovecommunicationqualityinnoisyenvironment.Becausepeoplehaslimitedknowledgeaboutnoisesignal,itisdifficulttofindageneralnoisemodelandageneralspeechenhancementapproach.Moreover,itishardtodistinguishbetweenspeechsignalandsomenoisesignalwhosepropertyissimilartospeechinmathematics.Sospeechenhancementisaspecialprobleminsignalestimation.Thisproblemcanbesolvedbystudyingmorespeechsignalprocessingtechnologyandlearninglinguisticsandperceptionpropertydeeply.Accordingtothedifferencenumbersofinputchannel,speechenhancementalgorithmcanbedividedintotwotypes.Onetypeisspeechenhancementalgorithmwithmulti-channelinput.Anotherisspeechenhancementalgorithmwithsingleinputchannel.Anewspeechenhancementalgorithmisproposed,whichisnamedadaptiveKLTspeechenhancementalgorithmwithpreprocessingVAD.Thatalgorithmisakindofalgorithmwithsignalinputchannelprocessingcolorednoise.Inproposedalgorithm,anadaptiveKLT(Karhunen-Loevetransform)speechenhancementalgorithmwithpreprocessingVADisstudied.InthisalgorithmspeechsignaldegradedbyadditivecolorednoiseisdecomposedintothecomponentsbyadaptiveKLTalongcleanspeechvectorspace.Eachcomponentismodifiedduetoitsnoiseandcleanspeechenergiesalongeacheigenvector.NoisespeechframeisdetectedbyVADwithspeechpreprocessingalgorithm,andnoiseenergyofnextnoisyspeechframeisestimated.Eachcomponentismodifiedaccordingtoanoptimizationcriterionoffrequencydomainconstraint.TheninverseKLTisconductedandanestimationoftheenhancedsignalissynthesized.ThealgorithmisemulatedinMATLAB,andisvalidatedintheory.ThenitisperformedrealtimerealizationonDSKboardofTIIncorporated.Objectivetestandsubjectivelisteningshowthatthealgorithmdemonstratesbetterperformanceinenvironmentofcolorednoise.Keywords:Speechenhancement;AdaptiveKarhunen-Loevetransform;VAD;DSK;Realtimerealizationi···································································································11.1···················································································11.2················································································21.2.1················································31.2.2················································41.3·····················································································12······································································142.1·························································································142.2·············································································162.3·································································192.4·····················································································19··························································213.1·················································································213.1.1··········································································213.1.2······································································223.2·························································243.3·····················································28···········································································································29VADKL·········304.1······························································304.2·········································································324.3·························································································334.3.1KLT···································································344.3.2·······················································374.3.3VAD··················································································38ii···········································································································41·························································································435.1··········································435.2KLT···········································475.2.1············································475.2.2··············································································50DSP························································526.1·····························································································526.1.1DSK······················································································526.1.2TLC320AD50C···················································536.1.3McBSP··················································546.2·····················································································566.2.1··································································576.2.2C·································································576.2.3······························································