hr_type4.m

很多matlab的源代码

function [Hr,w,d,L] = Hr_Type4(h)
% Computes Amplitude response Hr(w) of a Tyoe-3 Lp FIr filter
% -------------------------------------------------------------
% [Hr,w,d,L] = Hr_Type4(h)
% Hr = Amplitude Response
% w = frequencies between [0 pi] over which Hr is computed
% d = Type-4 LP filter cofficients
% L = Order of Hr
% h = Type-4 LP filter impulse response
%
M = length(h);
L = M/2;
d = 2*[h(L:-1:1)];
n = [1:1:L];
n = n-0.5;
w = [0:1:500]'*pi/500;
Hr = sin(w*n)*d';