资源描述：
《numerical fourier transforms dft and fft数值傅立叶变换dft和fft》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。
1、NumericalFourierTransformsDFTandFFTLeventSevgiDOGUSUniversity,ElectronicsandCommunicationEngineeringDepartmentZeametSokak,No21,Acıbadem,Istanbul,Turkey,lsevgi@dogus.edu.trAbstract-FrequencyanalysisisoneofthekeyissuesintheIEEESociety.Usingcomputersinnumericalcalculationsmean
2、smovingintoanon-physical,syntheticenvironment.Numerically,discreteorfastFouriertransformations(DFTorFFT)areusedtoobtainthefrequencycontentsofatimesignalandthesearetotallydifferentthanmathematicaldefinitionoftheFouriertransform.ThisarticlesimplereviewsDFTandFFTwithcharacteri
3、sticexamples.1.IntroductionTheanalysisofrealworldsignalsisafundamentalproblemformanyengineersandscientists,especiallyforelectricalengineerssincealmosteveryrealworldsignalischangedintoelectricalsignalsbymeansoftransducers,e.g.,accelerometersinmechanicalengineering,EEGelectro
4、desandbloodpressureprobesinbiomedicalengineering,seismictransducersinEarthSciences,antennasinelectromagnetics,andmicrophonesincommunicationengineering,etc.Traditionalwayofobservingandanalyzingsignalsistoviewthemintimedomain.BaronJeanBaptisteFourier[1],morethanacenturyago,sh
5、owedthatanywaveformthatexistsintherealworldcanberepresented(i.e.,generated)byaddingupsinewaves.Sincethen,wehavebeenabletobuild(breakdown)ourrealworldtimesignalintermsof(into)thesesinewaves.Itisshownthatthecombinationofsinewavesisunique;anyrealworldsignalcanberepresentedbyon
6、lyonecombinationofsinewaves[2].TheFouriertransform(FT)hasbeenwidelyusedincircuitanalysisandsynthesis,fromfilterdesigntosignalprocessing,imagereconstruction,stochasticmodelingtonon-destructivemeasurements.TheFThasalsobeenwidelyusedinelectromagneticsfromantennatheorytoradiowa
7、vepropagationmodeling,radarcross-sectionpredictiontomulti-sensorsystemsystemdesign.Forexample,thesplit-stepparabolicequationmethod(whichisnothingbutthebeampropagationmethodinoptics)hasbeeninusemorethandecadesandisbasedonsequentialFToperationsbetweenthespatialandwavenumberdo
8、mains.Twoandthreedimensionalpropagationproblemswithnon-flatrealisticterrainprofile
