4-19.m

matlab数字信号与应用源代码4

%例程4－19   Ⅲ、Ⅳ型理想带通滤波器的单位冲激响应 计算

function hd=ideal_bp2(Wcl,Wch,N)
%compute the ideal bandpass fiter unit pulse respondence hd(n)
%wcl: low cutoff frequency
%wch: high cutoff frequency
%N: window length
%hd: unit pulse respondence

alpha= (N-1)/2;
n=0:1:N-1;
m=n-alpha+eps;
hd=[cos(Wch*m)-cos(Wcl*m)]./(pi*m);