An IIR ALE based on constrained FIR filter

In this paper, we propose an adaptive algorithm for an IIR adaptive line enhancer (ALE) based on constrained FIR ADF. The two constraints that are considered are the unit norm constraint and zeros constraint. By incorporating these two constraints, we show that the effect of a white disturbance signal on the convergence of the ALE is eliminated in the mean sense. The mathematical analysis for exact modeling also indicates that there exists a solution, which gives perfect estimation of the frequencies of the sinusoidal signals. Furthermore, by using a sufficiently small step size and introducing a control mechanism, the convergence of a second order ALE is guaranteed even if there is a sudden change in the frequency of the input sinusoidal signal. Simulation results that are presented, verify these properties.