Comparison of Two Techniques For the Interpolation/Extrapolation of Frequency Domain Responses.

摘要

In a host of applications in engineering, it is necessary to obtain information about a system over a broad frequency range. In most cases, it is not possible to evaluate the parameter of interest in a closed form. However, either theoretical or experimental data is available in a narrow band. In this paper, a comparison is made between two methods that are used for interpolation/extrapolation of frequency domain responses. The first method discussed is a direct approach, derived from model based parameter estimation, which utilizes the principle of analytic continuation to interpolate/extrapolate the data over a wide band. The second uses the property of the discrete Hilbert Transform, based on the principle of causality, which relates the real and imaginary components of the frequency domain to iteratively interpolate/extrapolate the frequency response. The paper discusses the princlples behind each approach, and the algorithm used to implement the interpolation/extrapolation of frequency domain data, and then presents some numerical examples to compare the two methods.