Non-linear adaptive signal processor

This paper is a first attempt to give formalism to non-linear system design and in which context, related with similar linear processing techniques, they are located. A summary on the relation-ship of linear objectives and classical adaptive algorithms, in non-linear design problems, introduces the paper; giving the potential of random search techniques in order to open the different problems in non-linear objectives that could be handled with them. After, the similarity between probability distribution functions and power spectral density in linear processing is shown. This is supported by a nice example of non-linear system design. Finally, some prospective work is reported in the problem of adaptive companding design.