Super-Resolving a Frequency Band [Tips & Tricks]

This article introduces a simple formula that provides the exact frequency of a pure sinusoid from just two samples of its discrete-time Fourier transform (DTFT). Even when the signal is not a pure sinusoid, this formula still works in a very good approximation (optimally after a single refinement), paving the way for the high-resolution frequency tracking of quickly varying signals or simply improving the frequency resolution of the peaks of a discrete Fourier transform (DFT).