White noise process          

       One of the very important random processes is the white noise process. Noises in many practical situations are approximated by the white noise process. Most importantly, the white noise plays an important role in modelling of WSS signals.

       A white noise process is a random process that has constant power spectral density at all frequencies.Thus

where is a real constant and called the intensity of the white noise. The corresponding autocorrelation function is given by

where is the Dirac delta.