Pure tone 826809 226099368 2008-07-16T20:39:02Z Jim.henderson 2255048 [[Fourier theorem]] link A '''pure tone''' is a tone with with a sinusoidal waveshape. A [[sine wave]] is characterized by its ''frequency'' — the number of cycles per second, or its ''[[wavelength]]'' — the distance the waveform travels through its medium within a period, and the ''[[amplitude]]'' — the size of each cycle. A pure tone has the unique property that its waveshape and sound are changed only in amplitude and phase by linear acoustic systems. == Fourier theorem == The [[Fourier theorem]] states that any periodic waveform can be approximated as closely as desired as the sum of a series of sine waves with frequencies in a [[harmonic series (mathematics)|harmonic series]] and at specific [[phase (waves)|phase]] relationships to each other. The lowest of these frequencies (the [[fundamental frequency]]), which is also the inverse of the period of the waveform, determines the [[pitch (music)|pitch]] of the tone, which is perceived by the human hearing. In music, [[note]]s are assigned to tones with different fundamental frequencies, in order to describe the pitch of played tones. [[Category:Pitch]] [[Category:Sound]] [[Category:Noise pollution]] [[de:Sinuston]] [[pl:Ton (dźwięk)]] [[fi:Äänes]] [[it:Suono puro]] [[ja:純音]] [[sv:Sinuston]] [[zh:纯音]]