%% Group Delay Response of a Butterworth digitalFilter
% Use designfilt to design a sixth-order Butterworth Filter with normalized 3-dB frequency 0.2\pi rad/sample. Display its group delay response.

d = designfilt('lowpassiir','FilterOrder',6, ...
    'HalfPowerFrequency',0.2,'DesignMethod','butter');
grpdelay(d)

% Copyright 2015 The MathWorks, Inc.