Convergence analyses of stereo acoustic echo cancelers with preprocessing

The convergence properties of stereo acoustic echo cancelers with preprocessing are examined. We first elucidated the conditions of the paths from the talker to the microphones under which the nonuniqueness problem occurs. The degree of nonuniqueness was found to depend on the primeness of the paths. Next, the convergence rates of the acoustic echo cancelers with preprocessing were analyzed based on the independence theory for general cases and on the cyclostationarity of the input signal for the input-sliding method. The derived rates that depended on both of the period of the input signal and the order of the adaptive filter agreed well with the results of computer simulations.