Discrete spectrum

From Glossary of Meteorology

discrete spectrum

A spectrum in which the component wavelengths (and wavenumbers and frequencies) constitute a discrete sequence of values (finite or infinite in number) rather than a continuum of values.

A Fourier analysis of a function will yield a discrete spectrum only if the function is periodic, or is assumed to be so, or if the function is represented by a finite sample of its values. Fourier series may be used for the analysis.
See continuous spectrum.