MATLAB: Zpk in R2016b

zpk

I recently upgraded from R2016a to R2016b.
I get the following error when attempting to use the 'zpk' function:
"Undefined function 'zpk' for input arguments of type 'double'."
When I type "which zpk", I get:
C:\Program Files\MATLAB\R2016b\toolbox\dsp\filterdesign\@mfilt\zpk.m % mfilt method
Please help!

Best Answer

The version of the zpk function you have (in the Signal Processing Toolbox) returns the zero-pole-gain representation of a digital filter object created by the designfilt function.
Depending on what you want to do, consider using the roots or residue functions.
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