A new precise measurement method on interharmonics

For the signal containing the inter-harmonics, if the sample number is not equal to integer times of the signal period, the spectral leakages will occur in harmonic analysis based on DFT and affect the measurement accuracy. To improve the accuracy, different from other correction methods in which the long-range leakages are reduced by windowing the signal, a new interpolation algorithm is presented to correct both the long-range leakage and the short-range leakage at one time. The simulation results and experiment results show the measurement accuracy of the presented method is very high. The new algorithm is suitable for the precise harmonic analysis.