freqz_m.m

来自「很多matlab的源代码」· M 代码 · 共 19 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 compute over 0 to pi radians
% mag = absolute magnitude computed over 0 to pi radians
% pha = Phase reponse in radians over 0 to radians
% grd = Rroup delay over 0 to pi radians
% w = 501 frequency samples between 0 to pi radians
% b = numerator polynomial of H(z) (for FIR:b=h)
% a = denominator polynomial pf H(z) (for FIR:a=[1])
%
[H,w] = freqz(b,a,1000,'whole');
H = (H(1:1:501))';
w = (w(1:1:501))';
mag = abs(H);
db = 20*log10((mag+eps)/max(mag));
pha = angle(H);
grd = grpdelay(b,a,w);