Ip-DFT Based on Polynomial Interpolation and Newton-Raphson: A Multifrequency Estimation Alternative for Zero-Padding and Window Function Independence

The need for Zero-Padding alternatives for implementing the FFT technique with the ipDFT algorithm has received few citations in the literature. In the present work, we adapted the ipDFT problem to reflect the influence of Zeroes-Padded after the window function and proposed a practical approach to solve the problem adapted and fit to any window function adopted, with the help of the Lagrange Polynomial Interpolation technique and Newton-Raphson method. Finally, we present here the results of the current approach to the classical ipDFT technique (associated with the solution for Hann Window), as well as the application of the interpolated DFT method with two other window functions to serve as examples of the existing possibilities behind the solution proposed by the current work.