isminphase(h) determines if the filter object h is maximum phase, and returns 1 if true and 0 if false. adapfilt, dfilt, and mfilt objects work with isminphase.

isminphase(h,tolerance) uses input argument tolerance to determine whether the values of the filter transfer function zeros are close enough to 1 to be considered to be on the unit circle, returning 1 if true (the difference between the transfer function zero values and 1 is less than tolerance) and 0 if not.

The determination is based on the reference coefficients. A filter is minimum phase when the zeros of its transfer function are on or inside the unit circle, or the numerator is a scalar.

Examples

This example creates a minimum-phase filter.

fp = 200;
fst= 230;
fs = 900;
ap = 1;
ast= 80;
d = fdesign.lowpass('fp,fst,ap,ast',fp,fst,ap,ast,fs);
h = design(d,'equiripple','minphase',true);
isminphase(h)

ans =

     1

When you make h a fixed-point filter, the quantization process results in the filter no longer being minimum phase.

h.arithmetic='fixed';
isminphase(h)

ans =

     0

isminphase - Determine whether filter is minimum phase

Syntax

Description

Examples

See Also