Why is this matlab function causing trouble in the r2013a version?

Hi,

I just purchased the matlab r2013a software version. The code below was running without error in the previous version I had (r2011a). But when I run it in the r2013a version I get an error message.

Please help.

   function VowelFormants = FormantsExtraction (Vowel, fs)
   [Vowel fs]=wavread('SymphonyVowel.wav');
n = round(fs/1000) + 2;
w = hamming(length(Vowel));
Vowel = Vowel.*w;
th = ar(Vowel,n);    % auto-regressive model of voice
[b,a] = tfdata(th);       % transfer function of vocal tract
[h,w] = freqz(b,a);
 end

ERROR MESSAGE: Undefined function 'mrdivide' for input arguments of type 'cell'.

Error in freqz (line 101) [h,w,options] = firfreqz(b/a,options);

Error in FormantsExtraction (line 8) [h,w] = freqz(b,a); % frequency response of vocal tract

How can I fix this problem? Your help is much appreciated. Thank you.

[Walter Roberson]

tfdata() is from the Control Systems toolbox, which does not have a freqz(). Are you trying to use freqz() from the Signal Processing Toolbox or from the DSP Toolbox ?

[MatlabFan]

Thanks for commenting Walter.

I have

• matlab & simulink r2013a
• system identification toolbox
• database toolbox

So, I think I am trying to use it from the DSP System toolbox.

[Walter Roberson]

Are you sure? hamming() is from the Signal Processing Toolbox, unless you are using an implementation from the File Exchange.

[MatlabFan]

Since you said it, it is from the Signal Processing Toolbox. what are my options then?

[Walter Roberson]

Please show the output of

which ar(0)

and of

which -all ar
which -all tfdata

This will help me trace which routines are being called.

Notes to myself:

http://www.mathworks.com/help/ident/ref/ar.html

http://www.mathworks.com/help/ident/ref/tfdata.html

[MatlabFan]

- for which ar(0) the output is: C:\Program Files (x86)\MATLAB\R2013a Student\toolbox\ident\ident\ar.m

- for which -all ar the output is: C:\Program Files (x86)\MATLAB\R2013a Student\toolbox\ident\ident\ar.m

- for which -all tfdata the output is: C:\Program Files (x86)\MATLAB\R2013a Student\toolbox\shared\controllib\engine\@DynamicSystem\tfdata.m % DynamicSystem method

[Walter Roberson]

At the moment I do not understand why the ar() call did not fail, as you are not passing ar an iddata object as the documentation indicates it requires. The examples I find would have required that you used

Vowel = iddata(Vowel);

before the ar() call.

Without that iddata() call, I cannot predict what the output data type is from ar().

[MatlabFan]

Sir, the error message is the same even after I implemented

     Vowel = iddata(Vowel);

before the ar() call. The problem is definitely with the freqz() function.

Any more recommendations? Actually I hope you do have something for me.

[Walter Roberson]

I will be eating my meal now; I will continue my research later.

[MatlabFan]

Thank you. I appreciate your time.