FRF-based curve fitting is a process of matching a parametric model of an FRF (in a least squared error sense) to a set of experimental FRF data.
The unknown parameters of the parametric model are modal frequency, damping & residues (mode shape components)
The outcome of curve fitting is a set of modal parameters (frequency, damping & mode shape) for each mode that is identified in the frequency span of the experimental data.
After curve fitting is completed, mode shapes are stored into a Shape Table from which they can be displayed in animation on a 3D model of the test article.
Determine the Number of Modes in a frequency band of measurement data
Estimate modal Frequency & Damping for all modes in the frequency band
Estimate modal Residues (mode shape components) for each mode and each measurement