An adaptive system is one that is designed primarily for the purpose of
adaptive control and adaptive signal processing. Such a system usually has
some or all of the following characterisics:
Firstly they can automatically adapt in the face of changing environments
and changing system requirements.
Secondly they can be trained to perform specific filtering and decision
making tasks, i.e., they can be programmed by a training process. Because
of this adaptive systems donot require the elaborate synthesis procedures
usually needed for non-adaptive systems. Instead, they tend to be self
designing.
Thirdly, they can extrapolate a model of behaviour to deal with new situations
after having been trained on a finite and often small number of training
signals or patterns.
Fourthly, to a limited extent they can repair themselves, i.e., adapt
arround certain kinds of internal defects.
Fifthly, they are more complex and difficult to analyze than non-adaptive
systems, but they offer the possibility of substantially increased system
performance when input signal characteristics are unknown or time varying.