clear all; wlp=0.2*pi;wls=0.35*pi;wus=0.65*pi;wup=0.8*pi; B=wls-wlp; M=ceil(12*pi/B)-1; wp=[(wls+wlp)/2/pi，(wus+wup)/2/pi]; hn=fir1(M，wp，'stop'，blackman(M+1)); 运行该程序会显示如下错误： ??? Error using ==> fir1 at 92 The window l... clear all;
wlp=0.2*pi;wls=0.35*pi;wus=0.65*pi;wup=0.8*pi;
B=wls-wlp;
M=ceil(12*pi/B)-1;
wp=[(wls+wlp)/2/pi，(wus+wup)/2/pi];
hn=fir1(M，wp，'stop'，blackman(M+1));
运行该程序会显示如下错误：
??? Error using ==> fir1 at 92
The window length must be the same as the filter length.
具体该怎么解决那？
先看下fir1中的一段解释
For filters with a gain other than zero at Fs/2， e.g.， highpass
and bandstop filters， N must be even. Otherwise， N will be
incremented by one. In this case the window length should be
specified as N+2.
即高通、带阻滤波器的阶数应该控制为奇数，因为如果阶数为偶数，则在π点必有一零点，这对于高通带阻来说是不允许的，故取阶数为奇数，而你FIR1滤波器阶数为M+1阶，所以你的M必须为偶数，所以可以将程序改为
clear all;
clc
wlp=0.2*pi;wls=0.35*pi;wus=0.65*pi;wup=0.8*pi;
B=wls-wlp;
M=ceil(12*pi/B);
M=M+mod(M，2);
wp=[(wls+wlp)/2/pi，(wus+wup)/2/pi];
hn=fir1(M，wp，'stop'，blackman(M+1));
freqz(hn)
评论
QCNAN564 
长按识别二维码查看信息详情