Determination of a transfer function from amplitude frequency response data†

Abstract

0. linear system from its amplitude frequency response data is prosontod. Tho transfer function is the Lest in the least-squared-error sense. Frequency response data spanning several decades are weighted evenly, so t.J1C procedure gives a good fit at all data points. A magnitude-squared function is first found that best fits the frequency response data, and the minimum-phase transfer function is obtained from the magnitnde-squared function by spectral factorization. Examples arc used to illustrate the application of t.his procedure in system reduction and system ident.iIicut.ion.

A modified y‐parameter model for computer‐aided analysis using spice2

“…Because of having lower weights at lower frequencies, the low frequency F-parameter data have much less influence on the determination of approximation function coefficients A¡s and JB,'s [2]. This explanation can be verified by arbitrarily splitting the whole frequency range into two narrower ranges; and by doing the fitting for each of the two ranges.…”

On-line, closed-loop identification of multivariable systems

“…There are several methods for identification of nonparametric models [Godfrey (1980); Wellstead (1981)]. Different approaches have been applied to estimate transfer functions from frequency responses [Ausman (1964); Jong and Shanmugam (1977); Shieh and Cohen (1978); Lin and Wu (1982); Braun and Ram (1987); Sidman et al (1990)]. Linear least-squares methods for transfer function synthesis from frequency response data has been discussed by Levy (1959), Sanathanan and Koemer (1963), Payne (1970), Lawrence and Rogers (1979), Stahl (1984), and Whitfield (1986).…”

Frequency domain transfer function identification using the computer program SYSFIT

“…Time-domain constraint:, _such as a specified steady-state value) are added to the method in Payne (1970). The basic method of Levy (1959) is expanded in Jong and Shanmugam (1977) to fit a rninimum-phase model to the magnitude frequency response data of a system.…”