1、sprintf(A=%d,B=%d,C=%d,A,B,C)命令窗口输出结果:A=5.086632e+00,B=3.109529e+00,C=5.355640e-01%用改进的相关算法求幅值和相位z=3*sin(t);z1=3*cos(t);zz=z.*z;sz=s.*z;sz1=s.*z1;x1=length(sz);x2=length(zz);x3=length(sz1);rz=sum(zz)/x2;rsz=sum(sz)/x1;rsz1=sum(sz1)/x3;B=sqrt(2*rz);C=atan(rsz1/rsz);A=2*rsz/(B*cos(C);A=4.986266e+00,B=
2、2.998500e+00,C=5.264407e-01实验三设计一个巴尔低通滤波器%设计一个巴尔沃特低通滤波器,fp=1khz,fs=2khz,ap=1db,as=40db;fp=1000;fs=2000;wp=2*pi*fp;ws=2*pi*fs;ap=1;as=40;n,wc=buttord(wp,ws,ap,as,s);fprintf(阶数为%dn,n);num,den=butter(n,wc,%z,p,k=buttap(n);disp(分子多项式系数分别为%.4en,num);分母多项式系数分别为,den);w=wp ws;h1=freqs(num,den,w);Ap=%.4en,-2
3、0*log10(abs(h1(1);As=%.4en,-20*log10(abs(h1(2);w1=0:200:12000*pi;h=freqs(num,den,w1);gain=20*log10(abs(h);plot(w1/(2*pi),gain);xlabel(Hzylabel(dBtitle(幅频特性输出结果:阶数为8分子多项式系数分别为0.0000e+006.2187e+30分母多项式系数分别为1.0000e+003.6222e+046.5603e+087.7093e+126.4060e+163.8498e+201.6360e+244.5108e+27Ap=6.1668e-01As=
4、4.0000e+01图形为实验四 设计一个高通滤波器%设计一个高通滤波器fp=5khz,fs=1khz,ap=40db;fp=5000;fs=1000;wp=1/(2*pi*fp);ws=1/(2*pi*fs);阶数为disp(n);numt,dent=lp2hp(num,den,1);高通滤波器分子多项式系数,numt)高通滤波器分母多项式系数,dent)w=1/wp 1/ws;h1=freqs(numt,dent,w);,-20*log10(abs(h1(1)Bp=%.4en,-20*log10(abs(h1(2)h=freqs(numt,dent,w1);gain=20*log10(ab
5、s(h);频率幅值阶数为 4高通滤波器分子多项式系数高通滤波器分母多项式系数5.1920e+041.3478e+092.0497e+131.5585e+17Ap=1.0977e-01Bp=4.0000e+01 图形实验5 用FFT设计低通滤波器%用fft变换设计低通滤波器N=100;n=0:(N-1);fs=100;%采样频率f1=1;f2=10;y=sin(2*pi*f1/fs*n)+sin(2*pi*f2/fs*n);%原始信号subplot(211);plot(2*pi*f2/fs*n,y,k%显示波形时间原始信号ffty=fft(y);%进行快速傅里叶变换ffty1=ffty;ffty
6、1(f2/(fs/N)+1)=0;%f2频率对应的幅值为零ffty1(N-f2)/(fs/N)+1)=0;%f2/2频率对应f2的对称频率值对应幅值为零yy=ifft(ffty1);%逆fft变换subplot(212);plot(2*pi*f2/fs*n,yy);滤波以后的低频信号输出图形为实验六 用FFT高通滤波器设计ffty1(f1/(fs/N)+1)=0;ffty1(N-f1)/(fs/N)+1)=0;滤波以后的高频信号实验7 用双线性设计数字滤波器%用双线性设计数字滤波器,wp=0.2pi,ws=0.6Pi,ap=2db,as=15db;wp=0.2*pi;ws=0.6*pi;fs=
7、1/2;ap=2;as=15;Wp=2*fs*tan(wp/2);Ws=2*fs*tan(ws/2);n,wc=buttord(Wp,Ws,ap,as,numz,denz=bilinear(num,den,fs);分子多项式的系数,numz);分母多项式的系数,denz);h=freqz(numz,denz,w);ap=%.4fn,-20*log10(abs(h(1);as=%.4fn,-20*log10(abs(h(2);w=linspace(0,2*pi,1024);plot(w/pi,gain);Normalized frequencyGain,dBaxis(0 1 -50 0);gri
8、d;输出结果分子多项式的系数1.5777e-013.1555e-01分母多项式的系数-6.0620e-012.3730e-01ap=0.3945as=15.0000实验8切比雪夫1型设计低通和高通滤波器%用切比雪夫1型设计低通滤波器%wp=2*pi*1000,ws=2*pi*2000,ap=1,as=40;wp=2*pi*1000,ws=2*pi*2000,ap=1,as=40;n,wc=cheb1ord(wp,ws,ap,as,num,den=cheby1(n,ap,wc,%.4fn,num),den)h=freqs(num,den,w);w=0:12000*pi;plot(w/(2*pi)
9、,gain);0.00001202796127888840400.00001.00005886.214566671782.4829241699153902.8650904788863911639.0000ap=1.0000as=45.3060图形%用切比雪夫1型设计高通滤波器wp=2*pi*5000,ws=2*pi*1000,ap=1,as=40;wp=1/wp;ws=1/ws;numz,denz=lp2hp(num,den,1);h=freqs(numz,denz,w);ap=%.4enas=%.4enap=1.0000e+00as=4.7847e+01输出图形实验9 用切比雪夫2型设计低通
10、和高通滤波器%用切比雪夫2型设计低通滤波器n,wc=cheb2ord(wp,ws,ap,as,num,den=cheby2(n,as,wc,566.3919290688415499.929229837909134910329000.000024344.5782296168842.79422252800523365.803210820843108280358.000029837909134910292000.0000as=44.1570wp=2*pi*5000;ws=2*pi*1000;幅频特性曲线as=4.4779e+01实验10画一个信号的频谱图%画频谱图f1=50;f2=100;f3=20
11、0;N=100t=0:N-1;data=25+22*sin(2*pi*f1/fs*t)+30*sin(2*pi*f2/fs*t)+50*sin(2*pi*f3/fs*t);y = fft(data);yabs =abs(y);n = 0:N/2;yabs(1)=yabs(1)/2;stem(n*fs/N,2*yabs(1:N/2+1)/N);频谱图实验11 数字高通滤波器的设计%数字高通滤波器的设计,ws=0.2pi,wp=0.6pi,as=15,ap=2;用巴特沃斯滤波器设计。wp=0.6*pi;ws=0.2*pi;t=2;fs=1/t;wp=2/t*tan(wp/2);ws=2/t*tan
12、(ws/2);numg,deng=lp2hp(num,den,1);numz,denz=bilinear(numg,deng,fs);分子多项式的系数为分母多项式的系数为ap=%fnas=%fn0.01:1.2*pi;plot(w/(2*pi),20*log10(abs(h);分子多项式的系数为3.7521e-01-7.5042e-01分母多项式的系数为-3.1201e-011.8884e-01ap=0.394549as=15.000000输出图像用切比雪夫1型滤波器设计。1.7097e-01-3.4195e-015.6036e-014.2134e-01ap=2.000000as=28.530
13、518用切比雪夫2型滤波器设计。3.2784e-01-4.1044e-011.5646e-012.2258e-01as=20.237224%模拟带通滤波器的设计,wp1=6,wp2=8,ws1=4,ws2=11,ap=1.as=32;wp1=6,wp2=8,ws1=4,ws2=11,ap=1,as=32;b=wp2-wp1;w02=wp1*wp2;ws1=(ws1*ws1-w02)/(b*ws1);ws2=(ws2*ws2-w02)/(b*ws2);ws=min(abs(ws1),abs(ws2);wp=1;num,den=lp2bp(num,den,sqrt(w02),b);w=3:0.1:12;plot(w,20*log10(abs(h);wp1=6,wp2=8,ws1=4,ws2=11;w=ws1 wp1 wp2 ws2;set(gca,xti
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