Steady state analysis of an output signal based combination of two NLMS adaptive filters

This paper studies an affine combination of two NLMS adaptive filters, which is an interesting way of improving the performance of adaptive algorithms. The structure consists of two adaptive filters that adapt on the same input signal, one with a large and the other one with a small step size. The outputs of the individual filters are combined together with help of a parameter λ. Such a combination is capable of achieving fast initial convergence and small steady state error at the same time. In this paper we propose to compute the combination parameter λ from output signals of the individual filters and investigate the steady state performance of the resulting combined algorithm.