n.m

IIR-butter低通滤波器设计

wp=0.3*pi;
ws=0.4*pi;
Rp=3;
As=30;
T=1;
Pf=(2/T)*tan(wp/2);
Sf=(2/T)*tan(ws/2);
%巴特沃思型滤波器阶数
N=ceil((log10((10^(Rp/10)-1)/(10^(As/10)-1)))/(2*log10(Pf/Sf)));
fprintf('\n***巴特沃思型滤波器阶数=%2.0f \n',N)