Spectral Leakage
The spreading of spectral energy across neighboring frequency bins when finite observation windows do not align with the analyzed signal's periodic structure.
Signal Processing Context
Spectral leakage appears when a finite observation window does not contain an integer-period representation of a frequency component, spreading its energy across neighboring spectral bins. Window functions control the trade-off between main-lobe width and side-lobe attenuation.
Measurement Boundary
Leakage is distinct from aliasing: leakage arises from finite windowing, whereas aliasing arises when sampling cannot uniquely represent the input bandwidth.