Multifilters and prefilters: uniqueness and algorithmic aspects

In this paper we study the structure of prefilters which ensure a certain approximation order of a given multifilter system. Weshow how all prefilters can be obtained from the generic one and that in general these prefilters are necessarily rational filters, butpoint out how a judicious choice of parameters can be used to obtain FIR filters for the approximation orders 1, 2, 3. Moreover, weillustrate the results by giving prefilters for the standard examples of multiwavelets