數(shù)字信號處理byZaiyueYangCSE,ZJU,2016第5章數(shù)字濾波器的設(shè)計5.1數(shù)字濾波器的基本概念52模擬濾波器的設(shè)計5.3用脈沖響應(yīng)不變法設(shè)計ⅢR數(shù)字低通濾波器54用雙線性變換法設(shè)計IR數(shù)字低通濾波器5.5數(shù)字高通、帶通和帶阻濾波器的設(shè)計上一堂課學(xué)了些什么?DesignanalogApplyfreq.bandApplyfiltertransformationtransformationlowpassElterpecincationsDesiredmirButterworth,Chebyshev,脈沖響應(yīng)不變法LPtohP階躍響應(yīng)不變法Ellipse,Bessel,etcBPBS雙線性變換法HowtodesignanaloglowpassfiltersButterworth:H(jQ2)1+(Chebyshev(j2)21+cC2(Elliptic1+E/它們的特點是什么?如何確定它們的參數(shù)?UsingMatlabButterworth:buttap,buttord,butterChebyshev:cheblap,cheblord,cheby1,cheb2aphebard,cheby2Elliptic:ellipap,ellipord,ellipHowtotransformLPtoHP/BP/BsFrequencybandtransformations·LPtohe:·LPtoBP:gBQ·LPtobsBUsingmatlab仍然調(diào)用設(shè)計模擬低通濾波器的函數(shù)注意通帶和阻帶的截止頻率·LP:Ω.<g·HP:<g°BP:93<9n<9m<9BS:Ωn1<9x<923n<ma注意加high'、'stop7AnalogtoDigitallstoZDesigndigitalfilterH(z)foragivenanalogfilterHa(s)GeneralPrinciplePreservecertain"aspects"ofanaloganddigitalfiltersAspectsTransformationsShapeoftheimpulseresponseImpulseinvarianceakShapeofstepresponseStepinvarianceSystemfunctionrepresentationBilinears5.3脈沖響應(yīng)不變法PreservetheshapeoftheimpulseresponseThedigitalfilterimpulseresponselooks"similar"tothatofananalogfilter模擬濾波數(shù)字濾波器H(s)的器H(x)的單位沖擊單位脈沖響應(yīng)h(n)=h(t)len=h(nt采樣時間h(n)在采樣點上等于h(t)脈沖響應(yīng)不變法是一種時域逼近方法已知H。(s),尋找H(z),使得h(n)=h2(nT)Howtosolveit?H()=>A1.從H()到0)40=S1[B.