Measurement of harmonics/inter-harmonics of time-varying frequencies

A novel method of extraction and measurement of individual harmonics of a signal with time-varying frequency is presented. The proposed method is based on a nonlinear, adaptive mechanism. Compared with the well-established techniques such as DFT, the proposed method offers (i) higher degree of accuracy, (ii) structural/performance robustness, and (iii) frequency-adaptivity. The structural simplicity of the algorithm renders it suitable for both software and hardware implementations. The limitation of the proposed method as compared with DFT-based methods is its slower transient response. Based on simulation studies, performance of the method is presented and its accuracy and response time are compared with a DFT-based method.