Noise removal using adaptive noise cancellation algorithms in real time systems
In real time application adaptive noise cancellation uses single sensor for signal reception.The single sensor consist of a  delay  z-Δ to produce a delayed version of incoming signal d(n), denoted by x(n), which de-correlates the noise while leaving the target signal component correlated. So here not needed reference signal separately but delay creates uncorrelated noise from the incoming noise corrupted signal.