Harmonic Analysis and Simulation Study Using Triple-spectrum-line interpolation FFT Algorithm

There is hard to obtain the harmonic parameters exactly for the fast Fourier transform in situation of non-synchronous sampling. The cosine window and triple-spectrum-line interpolation FFT algorithm is presented to reduce spectral leakage and improve the accuracy of harmonic analysis. The windowed FFT transform is applied to the sampling signal using a good sidelobe characteristic window and discrete spectrum lines are obtained. The weighted arithmetic is operated by using three spectrum lines near the harmonic frequency point and the applicable rectifications of triple-spectrum-line FFT are deduced. Simulation results show that the algorithm has a higher accuracy of harmonic analysis compared with the cosine windowed double interpolation FFT in non-synchronized sampling.