Introduction

The field of adaptive systems design is one which may be regarded as mature, having been the subject of considerable research effort in the areas of control and signal processing for more than 30 years. Indeed a number of books [1,2,3,4,5] on the subject have appeared in recent years which serve to illustrate the range and diversity of adaptive systems. However none of these texts has provided a coherent framework within which it is possible to evaluate the range of adaptive algorithms available, and their comparative merits in terms of performance, complexity and stability. It is also clear from the published literature that algorithms relating to filters having finite impulse response (FIR) have been much more successful than those relating to infinite impulse response (IIR) filters.