A Flexible Window Function for Spectral Analysis [DSP Tips & Tricks]

This paper shows that the Butterworth window can be obtained by the conventional Butterworth filter design procedure. This window is able to control the 3-dB bandwidth and sidelobe attenuation independently by two parameters, the cutoff frequency and the order of the filter. As such, the sidelobe attenuation can be varied even if the 3-dB bandwidth is fixed, and vice versa. Therefore the tradeoff problem between the frequency resolution and spectral leakage in the estimated PSD, unavoidable with the conventional windows, can be solved by the Butterworth window.