Algorithm to Remove Spectral Leakage, Close-in Noise, and Its Application to Converter Test

A fundamental condition of using discrete Fourier is that the signal being transformed needs to be periodic and transform is performed on an integer number of these periods. In practice, due to some physical limitations, this condition is not always satisfied. A phenomenon known as leakage occurs and cause serious distortion in the transformed signal. Window functions are generally used at the expense of a reduced spectral resolution. Other alternative methods have also been proposed, but none of them offers the quality of direct Fourier transform of a periodic signal. This paper presents a new algorithm, called FXT, which produces equivalent spectral result with non-periodic signal as if the signal was periodic