hbfilt.m

里面囊括了基于matlab滤波器设计的各种.m文件

 % The design of halp-band filter by using the simple method
% according to the paper "Multirate filters, Filter Banks, Polyphase 
% Networks, and Applications: A Tutorial " 
% The input parameter N is odd integer. The result h is casual.

function h = hbfilt(N);
n = -(N-1)/2:-1;
neg_h = sin(pi*n/2)./(pi*n);
pos_h = sin(0.5*pi*(-n)*antieye((N-1)/2))./(pi*(-n)*antieye((N-1)/2));
h(1:(N-1)/2) = neg_h;
h((N+3)/2:N) = pos_h;
h((N+1)/2) = 1/2;
% Hamming window weighting, you can specify other form windows
h = h.*hamming(N)';
H = freqz(h,1,1000);
plot((0:999)/1000,dbvalue(abs(H)),'c');
title('Frequency Response of Half-band Filter');
axis([0,1,-100,10]);