Pure tone

In psychoacoustics, a pure tone is a sound with a sinusoidal waveform; that is, a sine wave of constant frequency, phase-shift, and amplitude.

A pure tone has the property – unique among real-valued wave shapes – that its wave shape is unchanged by linear time-invariant systems; that is, only the phase and amplitude change between such a system's pure-tone input and its output.

In clinical audiology, pure tones are used for pure-tone audiometry to characterize hearing thresholds at different frequencies.

[2][3] Pure tones have been used by 19th century physicists like Georg Ohm and Hermann von Helmholtz to support theories asserting that the ear functions in a way equivalent to a Fourier frequency analysis.

The percept of pitch depends on the frequency of the most prominent tone, and the phases of the individual components is discarded.