The Modified Basis Function Method for Time-Varying Frequency Estimation

A modified version of the basis function method, called the modified basis function method, is proposed for estimating time-varying frequency of nonstationary signals. The modification is accomplished by adjusting a TVAR process, used as a linear predictor, and applying a combination of both the forward and the backward predictors for calculating TVAR parameters. The time-varying frequency estimate was extracted from location of the closet pole to the unit circle in the complex z-plane. Two nonstationary signals, one is chirp and another is of sinusoidally time-

varying frequency, are used as examples. From our results, the proposed approach yielded better accuracy in estimating the time-varying frequency in either noisy or noise-free situation than using the traditional basis function method.

Keywords: Time-varying autoregressive, Modified Basic function method, Nonstationary signal, Frequency estimation

Corresponding author: E-mail: sodsri@su.ac.th