Signal Processing toolbox ver 6.22, Matlab ver 8.4 (R2014b)

I have a signal processing toolbox (ver 6.22) and am having problems running a script for butterworth filter (one that I have used many times without incident). I keep getting the error message: "Undefined function 'zp2ss' for input arguments of type 'double'", and, "Error in butter (line 97)[a,b,c,d] = zp2ss(z,p,k)". Not sure how to resolve this.

Thank you, Kathy Thomas

Answer 1

[Star Strider]

Probably the first step would be to type in the Command Window:

which zp2ss -all

and possibly also:

which butter -all

and see what returns.

Do your other Signal Processing Toolbox functions work?

[Kathy]

I have tried the which zp2ss and received a "not found" but when typing in which butter I received the below response:

>> which butter
C:\Program Files\MATLAB\R2014b\toolbox\signal\signal\butter.m
>> which zp2ss
'zp2ss' not found.

This is why I am concerned... I have another computer with an older version of Matlab which I have used no problems. Thought I have run this same script on the current computer and version in December so this is why I am concerned....

I can run spectral analysis on this computer.

[Steven Lord]

Sounds like your path may have been corrupted. Can you execute this command in your installation?

 ls('C:\Program Files\MATLAB\R2014b\toolbox\shared\controllib\general')

If so, and if it shows zp2ss.m, you may want to open the path tool (Set Path in the Environment section of the Home tab in the Toolstrip) and restore the default path.

If that directory does NOT contain that file, your installation may be corrupt instead of just your path. You may need to reinstall Signal Processing Toolbox in that case.

[Star Strider]

There’s nothing wrong with the path or toolboxcache or butter wouldn’t appear as it did.

You may have to reinstall the Signal Processing Toolbox on the machine that’s throwing the error. MathWorks Tech Support might have other approaches, so you might want to contact them, but they’ll likely give you the same solution.

[Steven Lord]

Star Strider, the toolbox/signal/signal directory (where BUTTER lives) may be on the path while toolbox/shared/controllib (where ZP2SS lives) is not.

Answer 2

[Image Analyst]

Try

>> restoredefaultpath

and try again. If that doesn't work, uninstall and reinstall. That's what I'd do. Or you can type

>> path

and see if you see this: C:\Program Files\MATLAB\R2015b\toolbox\shared\controllib\general