freqz_m.m

来自「the file contain many matlab signal sour」· M 代码 · 共 18 行

function [db,mag,pha,grd,w]=freqz_m(b,a);
% Modified version of freqz subroutine
% ---------------------
% [db,mag,pha,grd,w]=freqz_m(b,a);
% db=Relative magnitude in dB computed over 0 to pi radians
% mag=absolute magnitude computed over 0 to pi radians
% pha=Phase response in radians over 0 to pi radians
% grd=Group delay over 0 to pi radians
% w=501 frequency samples between 0 and pi redians
% b=numerator polynomial of H(z) (for FIR:b=h)
% a=denomintor polynomial of H(z) (for FIR:a=[1])
%
[H,w]=freqz(b,a,1000,'whole');
H=(H(1:501))';w=(w(1:501))';
mag=abs(H);
db=20*log10((mag+eps)/max(mag));
pha=angle(H);
grd=grpdelay(b,a,w);