ENHANCED SPECTRAL RESOLUTION FFT FOR STEP-LIKE SIGNALS

A method is presented for obtaining a sampled Fourier transform of a step-like signal with a spectral resolution greater than previously reported. The method is related to zero-padding which is used for enhancing the spectral resolution of an FFT of a limited duration signal. This new method involves final-value padding when the extension function outside the observation window is a step, or involves padding with a sampled exponential function when the extension function is a decaying exponential.