ensurethatthespectralcontentsofthecuttingsignalarepreserved,whilespuriousdataareminimized.Thedesignedfilterdoesnoteliminateallspuriouscomponents,butasubsequentDiscreteWaveletTransform(DWT)willenhancethecuttingforcesignalbyitsfilterbankproperty.Thewavelettransformbringsatime-frequencyrepresentationofasignalindecimatedformdependingontheapplicationdetaillevel;theresultwillbegivenastimedomainsamplesatthedecimatedfrequencyinacompressedform[].ThebasesoftheWaveletTransformarethewavelets,generatedfromabasicwaveletfunctionbydilationsandtranslations.Givenatime-varyingsignalf(t),awavelettransformationconsistsofcomputingcoefficientsthataretheinnerproductsofthesignalandafamilyofwavelets[].ByDWTweunderstandthecontinuouswaveletswiththediscretescaleandtranslationfactors[].TheDWTisdefinedasstatedinEq.(),wherecj,kiscalledthewaveletcoefficient正常刀具原始切削信号(b)正常刀具过滤切削信号(c)正常刀具原始数据段(d)正常刀具压缩数据段图B.(a)已损刀具原始切削信号(