Adaptive parallel-cascade truncated Volterra filters

This paper studies adaptive truncated Volterra filters employing parallel-cascade structures. Parallel-cascade realiza­ tions implement higher order Volterra systems as a parallel con­ nection of multiplicative combinations of lower order truncated Volterra systems. A normalized LMS adaptive filter is developed, and its performance capabilities are evaluated using a series of simulation experiments. The experimental results indicate that the normalized LMS adaptive parallel-cascade Volterra filter has superior convergence properties over several competing struc­ tures. This paper also includes an experiment that demonstrates the capability of the parallel-cascade adaptive system to reduce its implementation complexity by using fewer than the maximum number of branches required for the most general realization of the system.