A harmonic spectrum is a spectrum containing only frequency components whose frequencies are whole number multiples of the fundamental frequency; such frequencies are known as harmonics. "The individual partials are not heard separately but are blended together by the ear into a single tone." In other words, if is the fundamental frequency, then a harmonic spectrum has the form A standard result of Fourier analysis is that a function has a harmonic spectrum if and only if it is periodic. See also Fourier series Harmonic series (music) Periodic function Scale of harmonics Undertone series References Functional analysis Acoustics Sound