Using prewhitening and stepsize control to improve the performance of the LMS algorithm for acoustic echo compensation

An implementation of a compensator for acoustical echoes is presented. The algorithm consists of an adaptive transversal filter which is adjusted according to a modified version of the well-known normalized least mean square (NLMS) procedures. Decorrelation filters were added to improve the convergence. The step size was also varied according to the noise level to achieve the best performance in noisy environments. Some results are included of real-time measurements of the behavior in typical operating conditions, such as in hands-free telephone equipment, demonstrating the performance of the system.<
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