1、Ap,As为通带最大衰减和阻带最小衰减,以dB为单位。Wp,Ws为归一化通带截频和阻带截频,0Wp,Ws1。输出参数:N为滤波器的阶数;Wc为截频,0Wc(4)stop巴特沃斯带阻数字滤波器Columns1through70.0000-0.00000.0000-0.00000.0000-0.00000.0000Columns8through14-0.00000.0000-0.00000.0000-0.00000.0000-0.0000Columns15through210.0001-0.00010.0003-0.00070.0015-0.00290.0056Columns22through28
2、-0.01020.0179-0.03050.0502-0.07980.1227-0.1828Columns29through350.2636-0.36860.4998-0.65760.8396-1.04091.2534Columns36through42-1.46601.6661-1.84011.9753-2.06102.0904-2.0610Columns43through491.9753-1.84011.6661-1.46601.2534-1.04090.8396Columns50through56-0.65760.4998-0.36860.2636-0.18280.1227-0.0798
3、Columns57through630.0502-0.03050.0179-0.01020.0056-0.00290.0015Columns64through70-0.00070.0003-0.00010.0001-0.00000.0000-0.0000Columns71through77Columns78through81-0.00000.0000-0.00000.00000.0000-0.00010.0003-0.00110.0030-0.00740.0160-0.03180.0585-0.10080.1637-0.25190.3692-0.51740.6952-0.89801.1176-
4、1.34271.5597-1.75421.9125-2.02342.0794-2.07732.0188-1.90981.7596-1.57981.3828-1.18030.9828-0.79850.6332-0.49020.3705-0.27340.1970-0.13860.0953-0.06390.0419-0.02680.0167-0.01020.0061-0.00350.0020-0.00110.0006-0.00030.0002-0.00010.0000-0.00000.0000-0.00003(1)T0=204;N=205;T=1;k=0:T0;x=sin(2/8000)*770*p
5、i*k)+sin(2/8000)*1209*pi*k);subplot(2,1,1);stem(k,x);时域波形);Xm=fft(x,N)/N;f=(-(N-1)/2:(N-1)/2)/N/T;subplot(2,1,2);stem(f,abs(fftshift(Xm);频谱图N,Wc=buttord(0.1925,0.30225,3,60)subplot(4,1,1);subplot(4,1,2);y=filter(b,a,x);subplot(4,1,3);stem(k,y);低通滤波后时域波形ym=fft(y,N)/N;subplot(4,1,4);stem(f,abs(fftshif
6、t(ym);低通滤波后频谱图高通滤波后时域波形高通滤波后频谱图Wp1=680720/4000;Ws1=650-20720+20/4000;Rp1=3;Rs1=40;N1,Wn1=cheb1ord(Wp1,Ws1,Rp1,Rs1);b1,a1=cheby1(N1,Rp1,Wn1);freqz(b1,a1,512,8000);型切比雪夫滤波器1Wp2=750790/4000;Ws2=750-20790+20/4000;Rp2=3;Rs2=40;N2,Wn2=cheb1ord(Wp2,Ws2,Rp2,Rs2)b2,a2=cheby1(N2,Rp2,Wn2);figure;freqz(b2,a2,51
7、2,8000);型切比雪夫滤波器2Wp3=830870/4000;Ws3=830-20870+20/4000;Rp3=3;Rs3=40;N3,Wn3=cheb1ord(Wp3,Ws3,Rp3,Rs3)b3,a3=cheby1(N3,Rp3,Wn3);freqz(b3,a3,512,8000);型切比雪夫滤波器3Wp4=920960/4000;Ws4=920-20960+20/4000;Rp4=3;Rs4=40;N4,Wn4=cheb1ord(Wp4,Ws4,Rp4,Rs4);b4,a4=cheby1(N4,Rp4,Wn4);freqz(b4,a4,512,8000);型切比雪夫滤波器4grid
8、on;1:500;y1=filter(b1,a1,x);y2=filter(b2,a2,x);y3=filter(b3,a3,x);y4=filter(b4,a4,x);plot(k,y1,k,y2,g-,k,y3,r-,k,y4,y-滤波后4条输出曲线legend(697HZ,770HZ852HZ941HZWp1=11801220/4000;Ws1=1180-301220+30/4000;N1,Wn1=cheb1ord(Wp1,Ws1,Rp1,Rs1)Wp2=13101350/4000;Ws2=1310-301350+30/4000;N2,Wn2=cheb1ord(Wp2,Ws2,Rp2,R
9、s2);Wp3=14601500/4000;Ws3=1460-301500+30/4000;输出曲线1209HZ1336HZ1477HZ(5)x0=sin(2/8000)*941*pi*k)+sin(2/8000)*1336*pi*k);x1=sin(2/8000)*697*pi*k)+sin(2/8000)*1209*pi*k);x2=sin(2/8000)*697*pi*k)+sin(2/8000)*1336*pi*k);x3=sin(2/8000)*697*pi*k)+sin(2/8000)*1477*pi*k);x4=sin(2/8000)*770*pi*k)+sin(2/8000)*
10、1209*pi*k);x5=sin(2/8000)*770*pi*k)+sin(2/8000)*1336*pi*k);x6=sin(2/8000)*770*pi*k)+sin(2/8000)*1477*pi*k);x7=sin(2/8000)*852*pi*k)+sin(2/8000)*1209*pi*k);x8=sin(2/8000)*852*pi*k)+sin(2/8000)*1336*pi*k);x9=sin(2/8000)*852*pi*k)+sin(2/8000)*1477*pi*k);B1,A1=cheby1(N1,Rp1,Wn1);B2,A2=cheby1(N2,Rp2,Wn2)
11、;N3,Wn3=cheb1ord(Wp3,Ws3,Rp3,Rs3);B3,A3=cheby1(N3,Rp3,Wn3);B4,A4=cheby1(N4,Rp4,Wn4);wp1=11801220/4000;ws1=1180-301220+30/4000;rp1=3;rs1=40;n1,wn1=cheb1ord(wp1,ws1,rp1,rs1);b1,a1=cheby1(n1,rp1,wn1);wp2=13101350/4000;ws2=1310-301350+30/4000;rp2=3;rs2=40;n2,wn2=cheb1ord(wp2,ws2,rp2,rs2);b2,a2=cheby1(n2
12、,rp2,wn2);wp3=14601500/4000;ws3=1460-301500+30/4000;rp3=3;rs3=40;n3,wn3=cheb1ord(wp3,ws3,rp3,rs3);b3,a3=cheby1(n3,rp3,wn3);Y01=filter(B1,A1,x0);Y02=filter(B2,A2,x0);Y03=filter(B3,A3,x0);Y04=filter(B4,A4,x0);plot(k,Y01,k,Y02,k,Y03,k,Y04,输出曲线1y01=filter(b1,a1,x0);y02=filter(b2,a2,x0);y03=filter(b3,a3,x0);plot(k,y01,k,y02,k,y03,Y11=filter(B1,A1,x1);Y12=filter(B2,A2,x1);Y13=filter(B3,A3,x1);Y14=filter(B4,A4,x1);sub
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