www.gusucode.com > signal 案例源码程序 matlab代码 > signal/IIRFilterEffectiveImpulseResponseLengthDigitalFilterExample.m
%% IIR Filter Effective Impulse Response Length --- --- Digital Filter % Use |designfilt| to design a 4th-order lowpass elliptic filter with % normalized passband frequency $0.4\pi$ rad/sample. Specify 1 dB of % passband ripple and 60 dB of stopband attenuation. Determine the % effective impulse response sequence length and visualize it. % Copyright 2015 The MathWorks, Inc. %% d = designfilt('lowpassiir','FilterOrder',4,'PassbandFrequency',0.4, ... 'PassbandRipple',1,'StopbandAttenuation',60, ... 'DesignMethod','ellip'); len = impzlength(d) impz(d)