[Mataa-info] help with impedance model not working

[vero s. <swe...@gm...>]

Dear Matthias,

First let me say how glad i am to see that you are still supporting this
great suite of matlab tools with the latest release a few days ago - I
think it is a wonderful contribution to the audio community and really a
fine work!

I am just trying MATAA for the first time and one of the first task i'm
trying to experiment with is the impedance modeling and fitting functions.
 I thought I would try something simple, which is the following script (in
matlab 2014a)

%%%%%%%%%%%%%%%
Rdc = 5;
f0 = 100;
Qe = 0.5;
Qm = 3;
L1 = 0.002;
L2 = 0.001;
R2 = 1;

f = logspace(1,3,100);
[mag,phase] = mataa_impedance_speaker_model (f,Rdc,f0,Qe,Qm,L1,L2,R2);
 %generate impedance data
[Rdcf,f0f,Qef,Qmf,L1f,L2f,R2f] = mataa_impedance_fit_speaker (f,mag,phase);
 %recover the speaker parameters

%%%%%%%%%%%%%%%%


The mataa_impedance_speaker_model function works fine after a minor change
to the last line
%phase = arg (Z) / pi * 180;  %original
phase = angle (Z) / pi * 180;   % changed

but the\ function mataa_impedance_fit_speaker is giving me some problems.

The errors I get:
Error: File: mataa_impedance_fit_speaker.m Line: 86 Column:
11
The expression to the left of the equals sign is not a valid
target for an assignment.

These are related to the lines which read:
% find best-fit values of Rdc, f0, Q, L1, L2, and R2:
global ff = f;
global ff_low = f (i_low);
...

I assume these functions are working fine in the version of Matlab you have
(which version is that?) - are there known incompatibility issues with more
recent Matlab versions?

Lastly, I wanted to submit a feature request - have you considered adding
Farina sweep decomposition?  In this way, both the fundamental as well as
the harmonic distortion can be extracted from the same single sweep.   I
think the same exponential sweep from the generator can still be used, only
a new analysis function is needed.

Best wishes
Alex