Determination of a transfer function from phase response data

Transfer function identification from phase response data

“…Later on, Jong [4] introduced the rational approximation in (6) using a least-squares approach based on polynomial-based Sanathanan-Koerner (SK) algorithm [6]. However, the rational interpolation/approximation (6) is numerically difficult to achieve because of the large peaks of the tangent function [2].…”

“…First, as earlier proposed in [1], [4], we tried to calculate the rational approximation of the tangent function (6) Although not required by the procedure described in section 2, a rational approximation )…”

“…It is known from literature [4] that a transfer function can be determined from phase angle data by fitting the response of a tangent function using a polynomialbased Sanathanan-Koerner (SK) iteration. As shown in this paper, the reliability of this approach is sensitive to the dynamic behaviour of the tangent function, since it may contain a lot of sharp spikes which are difficult to approximate.…”