Extraction of nonstationary sinusoids

A novel met.hod of P.xtraction of nonstationary sinusoids and estimation of their parameters is presented. The proposed Algorithm has a noulinear stntcture which renders it fully adaptive in tracking time-variations in the parameters of the targeted sinwmid including its phase and frequency. Mathematic-al properties of the differential equations governing the proposed algorithm are presented and the performance of the propo!iled algorithm is demonstrated v,.;th the aid of computer simulat.ions. The proposed algorithm has be<>u digitally implemented on a digital signal processor (DSP) platform and the laboratory verification of it_., performance is presented. Superiority of the proposed algoritluu over convPntional Fourier analysis and linear aclaptiv<' methods is demonstrated by its successful application to a numb<.'r of reAl problems. Elimination of sinusoidal disturbances under time-varying conditions is a challenging problem of current research. The propo..c;ccl algorithm is employed to c:onstru<-t an adaptive notch filter for the rejedion of quosi-periodic intcrferen<-cs. Its perfonnanc.e is exemplified by its application to the problem of elimination of power line noise potPntially present on electrocardiogram m1d telephone cabks. Application of the proposed algorithm iu the estimation of low-level biomedicAl signals pollut<'d by noise constitutes another cxnmple of its superior pcrformall<.'C over conventional methods. Rcfinem<'nt and analysis of ultrasonic wavt:'!' used in non-dcstntctive testing (NDT) of materials is presented as another useful application of the proposed algorithm. Finally. estimation of instantaneous frcqucuey iu noise. exemplified by Doppler frequency shift estimation, is demonstrated. The proposed algorithm exhibits a high degree of immunity with regard to both external noise and internal para:neter settings while offering structural simplicity crucial for real-time applieations.