<unk>  is a mathematical tool used frequently in signal processing for analysing functions or series of values, such as time domain signals.  Informally, it is a measure of how well a signal matches a time-shifted version of itself, as a function of the amount of time shift. More precisely, it is the cross-correlation of a signal with itself.<unk>  is useful for finding repeating patterns in a signal, such as determining the presence of a periodic signal which has been buried under noise, or identifying the missing fundamental frequency in a signal implied by its harmonic frequencies.
Autocorrelation
Dominance relationship
Punctuation
Character displacement
Lotus effect
Relative volatility
Autocovariance
Unblinding