外文翻譯-數(shù)字濾波器的仿真與實現(xiàn)

鄭州輕工業(yè)學院畢業(yè)設計(論文)外文資料翻譯院系電子信息工程專業(yè)班級電子信息工程學生姓名靖世敏學號540901030111外文出處附件：1.外文資料翻譯譯文〔約3000漢字〕；2.外文資料原文(與課題相關的1萬印刷符號左右)。指導教師評語：指導教師簽名：年月日英文原文ThesimulationandtherealizationofthedigitalfilterWiththeinformationageandtheadventofthedigitalworld,digitalsignalprocessinghasbecomeoneoftoday'smostimportantdisciplinesanddoortechnology.Digitalsignalprocessingincommunications,voice,images,automaticcontrol,radar,military,aerospace,medicalandhouseholdappliances,andmanyotherfieldswidelyapplied.Inthedigitalsignalprocessingapplications,thedigitalfilterisimportantandhasbeenwidelyapplied.1、figuresUniton:AnaloganddigitalfiltersInsignalprocessing,thefunctionofafilteristoremoveunwantedpartsofthesignal,suchasrandomnoise,ortoextractusefulpartsofthesignal,suchasthecomponentslyingwithinacertainfrequencyrange.Thefollowingblockdiagramillustratesthebasicidea.Therearetwomainkindsoffilter,analoganddigital.Theyarequitedifferentintheirphysicalmakeupandinhowtheywork.Ananalogfilterusesanalogelectroniccircuitsmadeupfromcomponentssuchasresistors,capacitorsandopampstoproducetherequiredfilteringeffect.Suchfiltercircuitsarewidelyusedinsuchapplicationsasnoisereduction,videosignalenhancement,graphicequilibriuminhi-fisystems,andmanyotherareas.Therearewell-establishedstandardtechniquesfordesigningananalogfiltercircuitforagivenrequirement.Atallstages,thesignalbeingfilteredisanelectricalvoltageorcurrentwhichisthedirectanalogueofthephysicalquantity(e.g.asoundorvideosignalortransduceroutput)involved.Adigitalfilterusesadigitalprocessortoperformnumericalcalculationsonsampledvaluesofthesignal.Theprocessormaybeageneral-purposecomputersuchasaPC,oraspecializedDSP(DigitalSignalProcessor)chip.TheanaloginputsignalmustfirstbesampledanddigitizedusinganADC(analogtodigitalconverter).Theresultingbinarynumbers,representingsuccessivesampledvaluesoftheinputsignal,aretransferredtotheprocessor,whichcarriesoutnumericalcalculationsonthem.Thesecalculationstypicallyinvolvemultiplyingtheinputvaluesbyconstantsandaddingtheproductstogether.Ifnecessary,theresultsofthesecalculations,whichnowrepresentsampledvaluesofthefilteredsignal,areoutputthroughaDAC(digitaltoanalogconverter)toconvertthesignalbacktoanalogform.Notethatinadigitalfilter,thesignalisrepresentedbyasequenceofnumbers,ratherthanavoltageorcurrent.Thefollowingdiagramshowsthebasicsetupofsuchasystem.

Unitreferstotheinputsignalsusedtofilterhardwareorsoftware.Ifthefilterinput,outputsignalsareseparated,theyareboundtorespondtotheimpactoftheUnitisseparated,suchasdigitalfiltersfilterdefinition.Digitalfilterfunction,whichwastoimportsequencesXtransformationintoexportoperationsthroughaseriesY.Accordingtofiguresfilterfunction24-hourliveresponsecharacteristics,digitalfilterscanbedividedintotwo,namely,unlimitedlonglivelonglivethecorrespondingIIRfilterandthelimitedresponsetoFIRfilters.IIRfiltershavetheadvantageofthedigitalfilterdesigncanusesimulationresults,andsimulationfilterdesignofalargenumberoftablesmayfacilitatesimple.Itistheshortcomingsofthenonlinearphase;Linearphaseifrequired,willusetheentirenetworkphase-correction.Imageprocessingandtransmissionofdatacollectionisrequiredwithlinearphasefiltersidentity.AndFIRlinearphasedigitalfiltertoachieve,butanarbitrarymargincharacteristics.Impactfromthedigitalfilterresponseoftheunitscanbedividedintotwobroadcategories:theimpactofthelimitedresponse(FIR)filters,andunlimitednumberofshocksto(IIR)digitalfilters.FIRfilterscanbestrictlylinearphase,butbecausethesystemFIRfilterfunctionextremityfixedattheoriginalpoint,itcanonlyusethehighernumberofbandstoachievetheirhighselectivityforthesamefilterdesignindicatorsFIRfiltercalledbandthanafewhigh-IIR5-10times,thecostishigher,Signaldelayisalsolarger.Butifthesamelinearphase,IIRfiltersmustbenetwork-widecalibrationphase,thesamesectionalsoincreasethenumberoffiltersandnetworkcomplexity.FIRfilterscanbeusedtherecursivemethod,notinalimitedprecisionofashock,andintothehomesandquantitativefactorsofuncertaintyarisingfromtheimpactoferrorsthanIIRfiltersmallnumber,andFIRfiltercanbeusedFFTalgorithms,thecomputationalspeed.ButunlikeIIRfiltercanfilterthroughthesimulationresults,thereisnoready-madeformulaFIRfiltermustusecomputer-aideddesignsoftware(suchasMATLAB)tocalculate.So,abroaderapplicationofFIRfilters,andIIRfiltersarenotverystrictrequirementsonoccasions.Unitfromsub-functionscanbedividedintothefollowingfourcategories:(1)Low-filter(LPF);(2)high-filter(HPF);(3)belt-filter(BPF);(4)topreventfilter(BSF).Thefollowingchartdottedlinefortheidealsofthefilterfrequencycharacteristics:2、MATLABintroducedMATLABisamatrixlaboratory(MatrixLaboratory)isintended.Inadditiontoanexcellentvaluecalculationcapability,italsoprovidesprofessionalsymbolsterms,wordprocessing,visualizationmodeling,simulationandreal-timecontrolfunctions.MATLABastheworld'stopmathematicalsoftwareapplications,withastrongengineeringcomputing,algorithmsresearch,engineeringdrawings,applicationsdevelopment,dataanalysisanddynamicsimulation,andotherfunctions,inaerospace,mechanicalmanufacturingandconstructionfieldsplayinganincreasinglyimportantrole.AndtheClanguagefunctionrich,theuseofflexibility,high-efficiencygoalsprocedures.Highlanguagebothadvantagesaswellaslowlevellanguagefeatures.Therefore,Clanguageisthemostwidelyusedprogramminglanguage.AlthoughMATLABisacomplete,fullyfunctionalprogrammingenvironment,butinsomecases,dataandprocedureswiththeexternalenvironmentoftheworldisverynecessaryanduseful.FilterdesignusingMATLAB,couldbeadjustedwiththedesignrequirementsandfiltercharacteristicsoftheparameters,visualsimple,greatlyreducingtheworkloadforthefilterdesignoptimization.Intheelectricitysystemprotectionandsecondarycomputercontrol,manysignalprocessingandanalysisarebasedonarecertaintypessinusoidalwaveandthesecondharmonicsofthesystemvoltageandcurrentsignals(especiallyatDprocess),aremixedwithavarietyofcomplexcomponents,thefilterhasbeeninstalledpowersystemduringthecriticalcomponents.Currentcomputerprotectionandtheintroductionoftwodigitalsignalprocessingsoftwaremainfilter.Digitalfilterdesignusingtraditionalcumbersomeformula,theneedtochangetheparametersafterrecalculation,especiallyinhighfilters,filterdesignworkload.UsesMATLABsignalprocessingboxescanachieverapidandeffectivedigitalfilterdesignandsimulation.MATLABisthebasicunitofdatamatrix,withitsdirectivesexpressionmathematics,engineering,commonlyusedformisverysimilar,itisusedtosolveaproblemthaninMATLABC,FortranandotherlanguagesEndprecisionmuchthesamething.ThepopularMATLAB5.3/Simulink3.0includinghundredsofinternalfunctionwiththemainpackand30typesoftoolkits(Toolbox).kitscanbedividedintofunctionaltoolkitsanddisciplinestoolkit.MATLABtoolkitusedtoexpandthefunctionalsymbolsterms,visualizationmodelingsimulation,wordprocessingandreal-timecontrolfunctions.professionaldisciplinestoolkitisastrongertoolkits,toolkitscontrol,signalprocessingtoolkit,toolkits,etc.belongingtosuchcommunicationsMATLABuserstoopenwidelywelcomed.Inadditiontotheinternalfunction,allthepackagesMATLABtoolkitsarereadabledocumentandthedocumentcouldbeamended,modifiedorusersthroughoriginalprogramtheconstructionofnewprocedurestopreparethemselvesforkits.3、DigitalfilterdesignDigitalfilterdesignofthebasicrequirementsDigitalfilterdesignmustgothroughthreesteps:(1)Identificationofindicators:Inthedesignofafilter,theremustbesomeindicators.Theseindicatorsshouldbedeterminedonthebasisoftheapplication.Inmanypracticalapplications,digitalfiltersareoftenusedtoachievethefrequencyoperation.Therefore,indicatorsintheformofgeneraljurisdictiongivenfrequencyrangeandphaseresponse.Marginskeyindicatorsgivenintwoways.Thefirstisabsoluteindicators.ItprovidesafunctiontorespondtothedemandsofthegeneralapplicationofFIRfilterdesign.Thesecondindicatoristherelativeindicators.Itsvalueintheformofanswerstodecibels.Inengineeringpractice,themostpopularofsuchindicators.Forphaseresponseindicatorsforms,usuallyinthehopethatthesystemwithalinearphasefrequencybandshuman.Usinglinearphasefilterdesignwiththefollowingresponsetotheindicatorsstrengths：①itonlycontainsafewalgorithms,nopluraloperations；②thereisdelaydistortion,onlyafixedamountofdelay;③thefilterlengthN(numberofbandsforN-1),thevolumecalculationforN/2magnitude.(2)Modelapproach:Onceidentifiedindicatorscanuseapreviousstudyofthebasicprinciplesandrelationships,afiltermodeltobeclosertothetargetsystem.(3)Achieved:theresultsoftheabovetwofilters,usuallybydifferentialequations,systemfunctionorpulseresponsetodescribe.Accordingtothisdescriptionofhardwareorsoftwareusedtoachieveit.4、IntroductionofDSPToday,DSPiswidelyusedinthemoderntechnologyandithasbeenthekeypartofmanyproductsandplayedmoreandmoreimportantroleinourdailylifeRecently,NorthwesternPolytechnicalUniversityAviationMicroelectronicCenterhascompletedthedesignofdigitalsignalprocessorcoreNDSP25,whichisaimingatTMS320C25digitalsignalprocessorofTexasInstrumentTMS320series.Byusingtop2downdesignflowNDSP25iscompatiblewithinstructionandinterfacetimingofTMS320C25.Digitalsignalprocessors(DSP)isafitforreal-timedigitalsignalprocessingforhigh-speeddedicatedprocessors,themainvarietyusedforreal-timedigitalsignalprocessingtoachieverapidalgorithms.Intoday'sdigitalagebackground,theDSPhasbecomethecommunications,computer,andconsumerelectronicsproducts,andotherfieldsbaseddevice.Digitalsignalprocessorsanddigitalsignalprocessingisinseparably,weusuallysay"DSP"canalsomeanthedigitalsignalprocessing(DigitalSignalProcessing),isthatinthisdigitalsignalprocessorsLane.Digitalsignalprocessingisacovermanydisciplinesappliedtomanyareasanddisciplines,referstotheuseofcomputersorspecializedprocessingequipment,thesignalsindigitalformforthecollection,conversion,recovery,valuation,enhancement,compression,identification,processing,thesignalsarecompliantform.Digitalsignalprocessorsfordigitalsignalprocessingdevices,itisaccompaniedbyadigitalsignalprocessingtoproduce.DSPdevelopmentprocessisbroadlydividedintothreephases:the20thcenturytothe1970stheorythatthe1980sand1990sforthedevelopmentofproducts.BeforetheemergenceofthedigitalsignalprocessingintheDSPcanonlyrelyonmicroprocessors(MPU)tocomplete.However,theadvantageoflowerhigh-speedreal-timeprocessingcannotmeettherequirements.Therefore,untilthe1970s,atalentmadebasedDSPtheoryandalgorithms.WithLSItechnologydevelopmentin1982wasthefirstrecipientoftheworldgavebirthtotheDSPchip.Yearslater,thesecondgenerationbasedonCMOS工藝DSPchipshaveemerged.Thelate1980s,theadventofthethirdgenerationofDSPchips.DSPisthefastest-growing1990s,therehavebeenfoursuccessivefive-generationandthegenerationDSPdevices.After20yearsofdevelopment,theapplicationofDSPproductshasbeenextendedtopeople'slearning,workandallaspectsoflifeandgraduallybecomeelectronicsproductsdeterminants.中文翻譯數(shù)字濾波器的仿真與實現(xiàn)隨著信息時代和數(shù)字世界的到來，數(shù)字信號處理已成為當今一門極其重要的學科和技術領域。數(shù)字信號處理在通信、語音、圖像、自動控制、雷達、軍事、航空航天、醫(yī)療和家用電器等眾多領域得到了廣泛的應用。在數(shù)字信號處理應用中，數(shù)字濾波器十分重要并已獲得廣泛應用。1、數(shù)字濾波器介紹：模擬和數(shù)字濾波器在信號處理、過濾功能是一個不排除局部信息,如隨機噪音、提取有用的信號局部,如局部地勢在一定的頻率范圍.以下方框圖說明根本思路.有兩大類型的過濾,模擬以及數(shù)字.他們是完全不同的物理結構,如何工作.類比電子電路模擬用的過濾局部組成,例如由電阻、電容、放大器和生產所需的過濾效果.這種過濾器被廣泛使用的電路減少噪音等方面的應用,提高視頻信號、圖像均衡的高科技系統(tǒng)等眾多領域.有完善的技術標準設計的模擬電路進行過濾特定要求.在各個階段,是一個信號,是電機電壓和過濾,目前直接的物理模擬量(例如聲音或視頻信號和變頻器生產)處理.數(shù)碼過濾用數(shù)字進行數(shù)值計算處理器的信號抽樣值.處理器的可能通用計算機等PC或專業(yè)開展方案圖(數(shù)字信號處理器)芯片.模擬信號必須先投入使用的取樣和數(shù)碼藝術開展局(模擬到數(shù)字轉換器).由此二元多,占抽樣連續(xù)輸入信號的價值,轉移到處理器,進行數(shù)字計算.這些計算通常涉及多方面的投入和增加產品價值的共同因素.如有必要,這些計算結果,現(xiàn)在是抽樣信號值的過濾,產出通過開展援助委員會(類比數(shù)位轉換器來)信號轉換回模擬形式.看到一個數(shù)字過濾,信號是由一系列數(shù)字,而不是電壓或逆流.以下列圖表顯示了這種制度的根本格局：濾波器是指用來對輸入信號進行濾波的硬件或軟件。如果濾波器的輸入、輸出都是離散信號，那么該濾波器的沖擊響應也必然是離散的，這樣的濾波器定義為數(shù)字濾波器。數(shù)字濾波器的功能，就是把輸入序列X通過一定的運算變換成輸出序列Y。根據(jù)數(shù)字濾波器沖激響應函數(shù)的時域特性，可將數(shù)字濾波器分為兩種，即無限長沖激相應IIR濾波器和有限長沖激響應FIR濾波器。IIR數(shù)字濾波器的優(yōu)點是可以利用模擬濾波器設計的結果，而模擬濾波器的設計有大量圖表可查，方便簡單。它的缺點是相位的非線性；假設需要線性相位，那么要采用全通網(wǎng)絡進行相位校正。圖象處理以及數(shù)據(jù)采集傳輸都要求濾波器具有線性相位特性。而FIR數(shù)字濾波器可以實現(xiàn)線性相位，又可具有任意幅度特性。從數(shù)字濾波器的單位沖擊響應來看，可分為兩大類：有限沖擊響應〔FIR〕數(shù)字濾波器和無限沖擊響應〔IIR〕數(shù)字濾波器。FIR濾波器卻可以得到嚴格的線性相位，然而由于FIR濾波器的系統(tǒng)函數(shù)的極點固定在原點，所以只能用較高的階數(shù)來實現(xiàn)其高選擇性，對于同樣的濾波器設計指標，F(xiàn)IR濾波器所要求的階數(shù)要比IIR高5至10倍，所以本錢較高，信號延遲也較大。但是如果要求相同的線性相位，那么IIR濾波器就必須加全通網(wǎng)絡進行相位校正，同樣也要增加濾波器網(wǎng)絡的節(jié)數(shù)和復雜性。FIR濾波器可以用非遞歸的方法實現(xiàn)，在有限精度下不會產生振蕩，同時由于量化舍入以及系數(shù)的不確定性所引起的誤差的影響要比IIR濾波器小的多，并且FIR濾波器可以采用FFT算法，運算速度快。但是不象IIR濾波器可以借助模擬濾波器的成果，F(xiàn)IR濾波器沒有現(xiàn)成的計算公式，必須要用計算機輔助設計軟件〔如MATLAB〕來計算。由此可知，F(xiàn)IR濾波器應用比擬廣，而IIR濾波器那么用在相位要求不是很嚴格的場合。濾波器從功能上分又可分為如下4類:(1)低通濾波器(LPF)；(2)高通濾波器(HPF)；(3)帶通濾波器(BPF)；(4)帶阻濾波器(BSF)。理想濾波器的幅頻特性下列圖虛線為：2、MATLAB介紹：MATLAB是矩陣實驗室〔MatrixLaboratory〕之意。除具備卓越的數(shù)值計算能力外，它還提供了專業(yè)水平的符號計算，文字處理，可視化建模仿真和實時控制等功能。MATLAB作為世界頂尖的數(shù)學應用軟件，以其強大的工程計算、算法研究、工程繪圖、應用程序開發(fā)、數(shù)據(jù)分析和動態(tài)仿真等功能，在航空航天、機械制造和工程建筑等領域發(fā)揮著越來越重要的作用。而C語言功能豐富，使用靈活方便，目標程序效率高。既有高級語言的優(yōu)點，又有低級語言的特點。因此，C語言是目前應用最廣的編程語言。雖然MATLAB是一個完整的、功能齊全的編程環(huán)境，但在某些情況下，與外部環(huán)境的數(shù)據(jù)和程序的交互是非常必須而且有益的。利用MATLAB設計濾波器，可以隨時比照設計要求和濾波器特性調整參數(shù)，直觀簡便，極大的減輕了工作量，有利于濾波器設計的最優(yōu)化。在電力系統(tǒng)微機保護和二次控制中，很多信號的處理與分析都是基于正旋基波和某些整次諧波而進行的，而系統(tǒng)電壓電流信號〔尤其是故障瞬變過程〕中混有各種復雜成分，所以濾波器一直是電力系統(tǒng)二次裝置的關鍵部件。目前微機保護和二次信號處理軟件主要采用數(shù)字濾波器。傳統(tǒng)的數(shù)字濾波器設計使用繁瑣的公式計算，改變參數(shù)后需要重新計算，在設計濾波器尤其是高階濾波器時工作量很大。利用MATLAB信號處理箱可以快速有效地實現(xiàn)數(shù)字濾波器的設計與仿真。MATLAB的根本數(shù)據(jù)單位是矩陣，它的指令表達式與數(shù)學,工程中常用的形式十分相似,故用MATLAB來解算問題要比用C,FO