A step size control method steadily reducing acoustic echo even during double-talk

This paper proposes a step size control method capable of steadily canceling acoustic echo even during double talk. The method is characterized by applying a sub-adaptive filter to the control. The step size and the number of taps of the sub-adaptive filter are larger and fewer than those of the main adaptive filter used for canceling the acoustic echo, respectively. Accordingly, the sub-adaptive filter can reduce the residual echo more rapidly than the main adaptive filter. The proposed method applies the step size calculated using the residual echo to the main adaptive filter, and thereby, quickly and steadily reduces the acoustic echo. This paper finally verifies that the proposed method can provide almost the same convergence speed as that obtained by applying an optimum step size to the main adaptive filter.