%% Determine if Filter has Maximum Phase
% Design an allpass filter and determine if the filter has maximum phase.
% Using the dsp.AllpassFilter System object™, design an allpass filter that uses the minimum multiplier structure.

a = dsp.AllpassFilter

% Using the ismaxphase function, determine if the filter has maximum phase.

ismaxphase(a)

% Verify the location of poles and zeros of the filter transfer function on the z-plane. By definition, the zeros of the maximum phase filter must be outside the unit circle.

zplane(a)

%
% Copyright 2020 The MathWorks, Inc.