基于数字信号处理课程设计

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1、数字信号处理班级：13通信1班同组人：骆燕张逸媛鲁鑫a33李秀婷何思雨数字信号处理课程设计1、试设计一个模拟低通Butterworth滤波器解：经计算可知低通Butterworth滤波器的阶数为3用Matlab软件计算的程序如下：OmegaP=0.2*pi;OmegaS=0.3*pi;Rp=7;As=16;N=ceil(log10((10.^(0.1*abs(Rp))-1)./(10.^(0.1*abs(As))-1))/(2*log10(OmegaP/OmegaS)))运行程序后出来的结果如下图:使用Matlab软件仿真的程序如下：Wp=in

2、put('Normalizedpassbandedge=');Ws=input('Normalizedstopbandedge=');Rp=input('PassbandrippleindB=');Rs=input('MinimumstopbandattenuationindB=');[N,Wn]=buttord(Wp,Ws,Rp,Rs);[b,a]=butter(N,Wn);[h,omega]=freqz(b,a,512);plot(omega/pi,20*log10(abs(h)));grid;xlabel('omega/pi');yl

3、abel('GaindB');title('IIRButterworthLowpassFilter');得出的仿真波形如下：2、设Chebyshev模拟滤波器的技术指标Wc=2´p2kHz,Ws=2´p4kHz,在W=Ws处的衰减小于-15dB,通带波动参数，e2=0.2，求其阶数，并绘出幅频响应分贝图。解：经计算可知切比雪夫模拟滤波器的阶数为4用matlab计算的程序如下：clc;clearall;OmegaP=2*pi*2000;OmegaS=2*pi*4000;Rp=0.17;As=15;g=sqrt((10^(As/10)-1)/(10

4、^(Rp/10)-1));OmegaR=OmegaS/OmegaP;N=ceil(log10(g+sqrt(g*g-1))/log10(OmegaR+sqrt(OmegaR*OmegaR-1)))其计算结果显示如下：使用matlab软件仿真程序如下：clc;clearall;OmegaP=2*pi*2000;OmegaS=2*pi*4000;Rp=0.17;As=15;g=sqrt((10^(As/10)-1)/(10^(Rp/10)-1));OmegaR=OmegaS/OmegaP;N=ceil(log10(g+sqrt(g*g-1))/lo

5、g10(OmegaR+sqrt(OmegaR*OmegaR-1)));OmegaC=OmegaS;[z0,p0,k0]=cheb2ap(N,As);a0=real(poly(p0));aNn=a0(N+1);p=p0*OmegaC;a=real(poly(p));aNu=a(N+1);b0=real(poly(z0));M=length(b0);bNn=b0(M);z=z0*OmegaC;b=real(poly(z));bNu=b(M);k=k0*(aNu*bNn)/(aNn*bNu);b=k*bw0=[OmegaP,OmegaS];[H,w]

6、=freqs(b,a);Hx=freqs(b,a,w0);dbHx=-20*log10(abs(Hx)/max(abs(H)))plot(w/(2*pi)/1000,20*log10(abs(H)));xlabel('f(kHz)');ylabel('dB');axis([-1,12,-55,1]);set(gca,'xtickmode','manual','xtick',[0,1,2,3,4,5,6,7,8,9]);set(gca,'ytickmode','manual','ytick',[-50,-40,-30,-20,-10,0]);gr

7、id;显示结果如下图：3、用矩形窗、汉宁窗和布莱克曼窗设计FIR低通滤波器。程序为：clearall;N=11;n=1:N;wdhn=hamming(N);wdbl=blackman(N);w=boxcar(N);plot(n',[wdhn,wdbl,w])显示结果如下图：4、用matlab设计一个LPFFIRwp=0.24πws=0.28πas>=50dB绘出幅频响应分贝图解：设计Kaiser窗满足题意，利用Matlab软件可先求出窗口的介数以及β的值，经计算可知N=25，β=3.4493利用Matlab软件求值的程序如下：clc;clear

8、all;wp=0.24*pi;ws=0.28*pi;As=60;deltaf=(ws-wp)/(2*pi);N0=ceil((As-7.95)/(14