On the use of Pade approximants in the estimation of eigenfrequencies and damping ratios of a vibrating system

An approach to estimate eigenfrequencies and damping ratios of a vibrating system, in time domain from output data only, is studied. This approach is based on the interpretation of histograms obtained from the poles of Padé approximants. Using properties of the asymptotic location of poles of Padé approximants to rational functions, different subsets of eigenfrequencies and damping ratios are obtained and their histograms plotted. Numerical and experimental examples are presented.