ACCURACY OF FREQUENCY EVALUATION PERFORMED WITH THE PySINC SOFTWARE

Abstract

In this paper we present a direct method to determine the harmonic components of a signal. The method bases on the fact that the distribution of the samples in the spectrum derived with the Discrete Fourier Transform (DFT) follow the sinc function. We found a correction term that places the estimated frequency on an inter-line position. Therefore, the method implies first to find the two DFT samples that belong to the main lobe and then to simply calculate the correction term and add it to the frequency of the sample found on the left side of the main lobe. We created the PySINC software that uses this method, which is written in the Python language. Tests performed to find the accuracy of the frequency estimates show that the results are very accurate and we concluded that this method can be used with confidence for modal analysis issues.