用双线性变换法设计切比雪夫II型的数字IIR带通滤波器

《用双线性变换法设计切比雪夫II型的数字IIR带通滤波器》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、用双线性变换法设计切比雪夫II型的数字IIR带通滤波器用双线性变换法设计原型低通为切比雪夫II型的数字IIR带通滤波器，要求通带边界频率为400Hz，500Hz，阻带边界频率分别为350Hz，550Hz，通带最大衰减1dB，阻带最小衰减40dB，抽样频率为2000Hz，用MATLAB画出幅频特性，画出并分析滤波器传输函数的零极点；信号经过该滤波器，其中450Hz，600Hz，滤波器的输出是什么？用Matlab验证你的结论并给出的图形。Matlab详细设计：%DesignofaChebIIBandpassDigitalFilterbyusingbilinearmethodclc;cleara

2、ll;Rp=1;%bandpassattenuationindBRs=40;%bandstopattenuationindBOmegaS1_1=350;OmegaS1_2=550;OmegaP1_1=400;OmegaP1_2=500;Fp=2000;%samlingfrequencyWp1=2*pi*OmegaP1_1/Fp;Wp2=2*pi*OmegaP1_2/Fp;Ws1=2*pi*OmegaS1_1/Fp;Ws2=2*pi*OmegaS1_2/Fp;OmegaP1=2*Fp*tan(Wp1/2);%nonlinearlizationOmegaP2=2*Fp*tan(Wp2/2);%

3、nonlinearlizationOmegaS1=2*Fp*tan(Ws1/2);%nonlinearlizationOmegaS2=2*Fp*tan(Ws2/2);%nonlinearlizationOmegaP0=sqrt(OmegaP1*OmegaP2);%equivalentmidfrequencyBw=OmegaP2-OmegaP1;%bandwithEta_P0=OmegaP0/Bw;%NormalizationEta_P1=OmegaP1/Bw;%NormalizationEta_P2=OmegaP2/Bw;%NormalizationEta_S1=OmegaS1/Bw;%N

4、ormalizationEta_S2=OmegaS2/Bw;%NormalizationLemta_P_EquivalentLowPass=Eta_P2/(Eta_P2^2-Eta_P0^2);%changetotheequivalentLowpasspatameterLemta_S1_EquivalentLowPass=-Eta_S1/(Eta_S1^2-Eta_P0^2);%changetotheequivalentLowpasspatameterLemta_S2_EquivalentLowPass=Eta_S2/(Eta_S2^2-Eta_P0^2);%changetotheequi

5、valentLowpasspatameterLemta_S_EquivalentLowPass=min(Lemta_S1_EquivalentLowPass,Lemta_S2_EquivalentLowPass);%getthesmallest%EstimatetheFilterOrder[N,Wn]=cheb2ord(Lemta_P_EquivalentLowPass,Lemta_S_EquivalentLowPass,Rp,Rs,'s');%DesigntheFilter[num1,den1]=cheby2(N,Rs,Wn,'s');[num2,den2]=lp2bp(num1,den

6、1,OmegaP0,Bw);[num,den]=bilinear(num2,den2,Fp);%Computethegainresponsew=0:pi/255:pi;h=freqz(num,den,w);g=20*log10(abs(h));%Plotthegainresponsefigure;plot(w/pi,g);gridaxis([01-605]);xlabel('omega/pi');ylabel('GainindB');title('GainResponseofaChebIIBandpassFilter');%Plotthepolesandzeros[z,p,k]=tf2

7、zp(num,den);figure;zplane(z,p);%»æÖÆ´«Ê亯ÊýÁ㼫µãtitle('´«Ê亯ÊýµÄÁ㼫µã')f1=450;f2=600;t=0:0.0001:1x1=sin(2*pi*f1*t);x2=sin(2*pi*f2*t);x=x1+x2;figure;subplot(2,2,1)%»æÖÆx1µÄ²¨ÐÎplot(x1);gridon;axis([0,50*pi,-3,