bpiir3cheb2.m

matlab IIR带通 滤波器设计 m文件 巴特沃斯

clc;
Fs=8000;		% Sampling frequency 8 kHz
Fls=270;
Flp=280;
Fup=320;
Fus=330;

Wp=[2*Flp/Fs,2*Fup/Fs];	% Normalized passband edge frequency
Ws=[2*Fls/Fs,2*Fus/Fs];	% Normalized stopband edge frequency

Rp=1;			% Passband ripple in dB
Rs=20;		    % Stopband attenuation in dB

[N,Wn]=cheb2ord(Wp,Ws,Rp,Rs); 
[b,a]=cheby2(N,Rs,Wn);
[hw,w]=freqz(b,a);
subplot(3,2,1);
plot(w/pi,20*log10(abs(hw)));grid
axis([0,1,-80,5]);xlabel('ω/π');
ylabel('幅度（dB）')
subplot(3,2,3);plot(w/pi,angle(hw));
grid;axis([0,1,-pi,pi]);
xlabel('ω/π');ylabel('相位（rad）');

[Z,P,K]=tf2zp(b,a);		% Transfer function to zero-pole
[sos,G]=zp2sos(Z,P,K)		% Zero-pole to 2nd-order section

Coeff1=sos( : ,[5,6] )*16384;
Coeff2=sos( : ,[1,2,3] )*16384;
Coeff2=Coeff2*0.5555;
Coeff=[Coeff1,Coeff2];
Coeff=round(Coeff)