Pink Noise
A random-like signal in which power is proportional to the inverse of frequency. At twice the frequency, we would expect half the power, which is a 3dB decrease. This is a frequency-response slope of -3dB / octave, or -10dB/decade. As opposed to white noise, which has the same level at all frequencies, pink noise has more low-frequency or "red" components, and so is called "pink".
Narrow band analysis will show a fall in level with increasing frequency, but third-octave band or octave band analysis will be flat.
Pink noise is often produced by filtering white noise and has the same power within each octave.
See also: White Noise.
Subjects: Noise & Vibration