Fundamental Issues in Spectrum Measurement

Insight into spectrum measurement is provided regarding the possibility of achieving a unified definition of the measurand for important classes of phenomena, including periodic, transitory impulsive, stochastic stationary, and stochastic non-stationary ones. Furthermore, the notion of characterizing the observation window as a key feature of the measurement method is introduced, and the issue of reducing the variability of the results is discussed, with a focus on the key role that can be played by the multi-taper method.