A Technique for Using a Time-Multiplexed Second-Order Digital Filter Section for Performing Adaptive Filtering

Digital filters are commonly designed in the form of a cascade of recursive second-order sections. Filters designed this way can be realized, in hardware, by building a single second-order section and then time multiplexing it to perform all the required operations. On the other hand, adaptive filters, such as adaptive equalizers, are generally nonrecursive. In this paper, a technique is described for modifying a time-multiplexed recursive second-order section so that it can be used to realize both recursive cascade-form filters and nonrecursive adaptive filters.