User`s guide

Parametric Fitting
3-53
Note that the toolbox includes the Fourier series as a nonlinear library
equation. However, the library equation does not meet the needs of this
example because its terms are defined as fixed multiples of the fundamental
frequency w. Refer to “Fourier Series” on page 3-16 for more information.
The numerical results shown below indicate that the fit does not describe the
data well. In particular, the fitted value for
c1 is unreasonably small. Because
the starting points are randomly selected, your initial fit results might differ
from the results shown here.
To assist the fitting procedure, constrain
c1 to a value between 10 and 14. To
define constraints for unknown coefficients, use the Fit Options GUI, which
you open by clicking the
Fit options button in the Fitting GUI.
Constrain the cycle to be
between 10 and 14 months.