Fitting complex functions with real fitting parameters
Fitting complex functions with real fitting parameters
(OP)
Hi All:
I have a problem which should be easy to solve, however I cannot manage to do it.
I am trying for the first time to fit complex impedance data with equivalent circuits using mathcad programs like Complex_Fit.mcd, or Least_Squared_Error.mcd. The fitting procedure itself works, however I always obtain complex fitting parameters which does not make sense, e.g. an Ohmic resistance should always be real. I defined the guess values as reals, e.g. R=30+i*0, but the ouput is still complex. Any suggestions how to avoid complex solutions?
I have a problem which should be easy to solve, however I cannot manage to do it.
I am trying for the first time to fit complex impedance data with equivalent circuits using mathcad programs like Complex_Fit.mcd, or Least_Squared_Error.mcd. The fitting procedure itself works, however I always obtain complex fitting parameters which does not make sense, e.g. an Ohmic resistance should always be real. I defined the guess values as reals, e.g. R=30+i*0, but the ouput is still complex. Any suggestions how to avoid complex solutions?





RE: Fitting complex functions with real fitting parameters
Apart from being a good pun, it means that real world impedances are complex and if you get complex solutions, you have to use them.
RE: Fitting complex functions with real fitting parameters
In reality small R-s have +,large - immaginary component.
Complex result in case of real date may be due to
calculation/rounding errors.
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032
RE: Fitting complex functions with real fitting parameters
TTFN
RE: Fitting complex functions with real fitting parameters
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032