About Signals' Spectrum

Abstract

Due to this Fourier series exclusive interpretation applied to periodical signals, which shows that a stationary harmonic signal with a single pulsation  cannot contain components of other pulsations but its own pulsation  , there is the opinion that stationary harmonic signals cannot stimulate physical systems which have their own pulsations different from  . The authors’ research have demonstrated that this theory is not true. More than this, signals considered identical, that is with identical amplitudes, phases and pulsations, are not identical from the spectral point of view if the signals have different durations and this can be noticed in many practical situations.