Recursive processing by noncausal digital filters

Digital filters having exactly linear phase are usually realized by nonrecursive systems. However, the filter degree, and thus the expense, becomes rather large in the case of steep filters with high attenuation in the stopband. This paper deals with an alternative possibility using noncausal recursive systems After known methods are generalized, suitable algorithms are proposed and systematic errors are investigated. Finally, the method is compared with nonrecursive filtering.