华科电气带通滤波器设计Matlab仿真代码与图片.docx

基于频域抽样法的FIR数字带通滤波器设计wsl=0.12*pi; wsh=0.82*pi; wpl=0.32*pi; wph=0.62*pi; delta=(wpl-wsl); M=ceil(2*pi*3/delta); al=(M-1)/2; wl=(2*pi/M); k=0:M-1; T1=0.12;T2=0.6;Hrs=[zeros(1,ceil(0.12*pi/wl)+1),T2,T1,ones(1,ceil(0.3*pi/wl)),T1,T2,zeros(1,ceil(0.3734*pi/wl)),T2,T1,ones(1,ceil(0.3*pi/wl)),T1,T2,zeros(1,ceil(0.12*pi/wl)+1)]; wdl=[0 0.12 0.32 0.62 0.82 1]; k1=0:floor((M-1)/2);k2=floor((M-1)/2)+1:M-1;angH=[-al*(2*pi)/M*k1,al*(2*pi)/M*(M-k2)]; H=Hrs.*exp(j*angH); h=real(ifft(H));%傅立叶反变换figure(1);%冲击响应图stem(k,h); title(impulse response); xlabel(n);ylabel(h(n)); grid; figure(2);%幅频曲线图Hf=abs(H);w=k*wl/pi; plot(w,Hf,*b-) axis([0 1 -0.1 1.1]); title(amplitude response); xlabel(frequency in pi units);ylabel(Hr(w)); set(gca,xtickmode,manual,xtick,wdl); set(gca,ytickmode,manual,ytick,[0 0.12 0.6 1]); grid; figure(3); fs=15000; [c,f3]=freqz(h,1); f3=f3/pi*fs/2; plot(f3,20*log10(abs(c))); title(频谱特性); xlabel(频率/HZ);ylabel(衰减/dB); grid; t=(0:100)/fs; x=sin(2*pi*t*700)+sin(2*pi*t*3200)+sin(2*pi*t*6200); q=filter(h,1,x); [a,f1]=freqz(x); f1=f1/pi*fs/2; [b,f2]=freqz(q); f2=f2/pi*fs/2; figure(4); subplot(2,1,1); plot(f1,abs(a)); title(输入波形频谱图); xlabel(频率);ylabel(幅度) subplot(2,1,2); plot(f2,abs(b)); title(输出波形频谱图); xlabel(频率);ylabel(幅度)基于频域抽样法的FIR数字带通滤波器设计 wsl=0.12*pi;%低阻带边缘 wsh=0.82*pi;%高阻带边缘 wpl=0.32*pi;%低通带边缘 wph=0.62*pi;%高通带边缘 delta=(wpl-wsl);%过度带 M=ceil(2*pi*3/delta);%抽样点数 al=(M-1)/2; wl=(2*pi/M); %抽样间隔 k=0:M-1; T1=0.12; T2=0.6;%过渡带样本点 Hrs=[zeros(1,ceil(0.12*pi/wl)+1),T2,T1,ones(1,ceil(0.3*pi/wl)),T1,T2,zeros(1,ceil(0.3734*pi/wl)),T2,T1,ones(1,ceil(0.3*pi/wl)),T1,T2,zeros(1,ceil(0.12*pi/wl)+1)]; wdl=[0 0.12 0.32 0.62 0.82 1]; k1=0:floor((M-1)/2);k2=floor((M-1)/2)+1:M-1; angH=[-al*(2*pi)/M*k1,al*(2*pi)/M*(M-k2)]; H=Hrs.*exp(j*angH); h=real(ifft(H));%傅立叶反变换 figure(1);%冲击响应图 stem(k,h); title(impulse response); xlabel(n);ylabel(h(n)); grid; figure(2);%幅频曲线图 Hf=abs(H);w=k*wl/pi; plot(w,Hf,*b-) axis([0 1 -0.1 1.1]); title(amplitude response); xlabel(frequency in