外文翻译---fir数字滤波器的设计

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1、FIRDigitalFilterDesignInchapter9weconsideredthedesignofIIRdigitalfilters.Forsuchfilters,itisalsonecessarytoensurethatthederivedtransferfunctionG(z)isstable.Ontheotherhand,inthecaseofFIRdigitalfilterdesign,thestabilityisnotadesignissueasthetransferfunctionisapolynomialinz-1andisthusalwaysguaranteedst

2、able.Inthischapter,weconsidertheFIRdigitalfilterdesignproblem.UnliketheIIRdigitalfilterdesignproblem,itisalwayspossibletodesignFIRdigitalfilterswithexactlinear-phase.First,wedescribeapopularapproachtothedesignofFIRdigitalfilterswithlinear-phase.Wethenconsiderthecomputer-aideddesignoflinear-phaseFIRd

3、igitalfilters.Tothisend,werestrictourdiscussiontotheuseofmatlabindeterminingthetransferfunctions.SincetheorderoftheFIRtransferfunctionisusuallymuchhigherthanthatofanIIRtransferfunctionmeetingthesamefrequencyresponsespecifications,weoutlinetwomethodsforthedesignofcomputationallyefficientFIRdigitalfil

4、tersrequiringfewermultipliersthanadirectformrealization.Finally,wepresentamethodofdesigningaminimum-phaseFIRdigitalfilterthatleadstoatransferfunctionwithsmallergroupdelaythanthatofalinear-phaseequivalent.Theminimum-phaseFIRdigitalfilteristhusattractiveinapplicationswherethelinear-phaserequirementisn

5、otanissue.10.1preliminaryconsiderationsInthissection,wefirstreviewsomebasicapproachestothedesignofFIRdigitalfiltersandthedeterminationofthefilterordertomeettheprescribedspecifications.10.1.1BasicApproachestoFIRDigitalFilterDesignUnlikeIIRdigitalfilterdesign,FIRfilterdesigndoesnothaveanyconnectionwit

6、hthedesignofanalogfilters.ThedesignofFIRfiltersisthereforebasedonadirectapproximationofthespecifiedmagnituderesponse,withtheoftenaddedrequirementthatthephaseresponsebelinear.RecallacausalFIRtransferfunctionH(z)oflengthN+1isapolynomialinz-1ofdegreeN:(10.1)Thecorrespondingfrequencyresponseisgivenby(10

7、.2)Ithasbeenshowninsection5.3.1thatanyfinitedurationsequencex[n]oflengthN+1iscompletelycharacterizedbyN+1samplesofitsdiscrete-timeFouriertransformX.Asaresult,thedesignofanFIRfilteroflengthN+1canbeacco