An Improvement of the Nonparametric Frequency Estimation Below Two Signal Periods Using Two Windows

This article presents a method for improving the nonparametric frequency estimation of the fundamental periodicity of a multifrequency signal when a smaller number of periods are covered—up to two periods in the measurement time. The estimation procedure uses the weights of two Rife-Vincent I (RV1) windows on the same set of acquired signal samples and then uses a combination of two consecutive discrete Fourier transform (DFT) amplitude coefficients in the quotient. To reduce the harmonic influence, the technique of near-coherent frequency evaluation is used, and to reduce the interharmonic influence, a method can be added, where the rest of the signal is averaged after determining the periodic part of the signal. The simulation and experimental results obtained show a very good compromise between fast and accurate estimation.