1/f noise

Spectrum of a pink noise approximation on a log-log plot. Power density falls off at 10 dB/decade of frequency.
Spectrum of a pink noise approximation on a log-log plot. Power density falls off at 10 dB/decade of frequency.

1/f noise or pink noise is a mathematical equation that relates the power of the signal to the signal's frequency. A signal's power measurement will be 1/frequency, which is a power law relationship.