Spectrum (physical sciences)

optical phenomenon

difference between the upper and lower frequencies passed by a filter, communication channel, or signal spectrum

thumb|250px|The node (physics)|nodes of a vibrating string are harmonics. thumb|Two different notations of natural harmonics on the cello. First as sounded (more common), then as fingered (easier to sightread).

Instrument that measures the magnitude of an input signal versus frequency within the full frequency range of the instrument

thumb|upright=1.35|Spectrogram of the spoken words "nineteenth century". Frequencies are shown increasing up the vertical axis, and time on the horizontal axis. The legend to the right shows that the color intensity increases with the density. thumb|upright=1.35|A 3D spectrogram: The RF spectrum of a battery charger is shown over time

lowest frequency of a periodic waveform, such as sound

spreading the frequency domain of a signal

relative importance of certain frequencies in a composite signal

sound with a sinusoidal waveform

laser source emitting in equally spaced frequency lines

Part of a spectrum

audio frequencies used for the transmission of speech

effect in signal processing

wavelength interval over which the magnitude of all spectral components is equal to or greater than a specified fraction of the magnitude of the component having the maximum value

analisis spectral