On “A Flexible Window Function for Spectral Analysis” [Letter to Editor]

In March 2010, a windowing function that is based on the well-known Butterworth filters was proposed [1] with the claim that it can solve “the tradeoff problem between the frequency resolution and spectral leakage in the estimated power spectral density, unavoidable with the conventional windows.” That claim is a consequence of not considering the available time duration in the window design for which we provide an illustration in this comment correspondence.