A combination of two NLMS filters in an adaptive line enhancer

In this paper we study an adaptive line enhancer, the adaptive algorithm of which is based on an affine combination of two adaptive filters. Combination of adaptive filters is an interesting way of improving the performance of adaptive algorithms. The adaptive structure consists of two NLMS adaptive filters that adapt on the same input signal. One of the filters has a large and the other one a small step size. Such a combination is capable of achieving fast initial convergence and small steady state error at the same time. In this paper we study the second order statistics of the output signal of a line enhancer based on a combination of two adaptive filters in steady state.