An Echo Canceller Using Smoothed-coefficient Filter with Adaptive Time Constant Controlled by High-pass Errors

This paper proposes a double-talk-robust echo canceller using a smoothed-coefficient filter (SCF). The SCF’s tap coefficients are obtained by smoothing those of a pilot adaptive filter (PAF) for better accuracy and stability. The smoothing time constant is controlled by comparing mean squared high-pass errors of the SCF and the PAF. The high-pass filters enable precise control of the SCF by eliminating low frequency components of the near-end signal which cause comparison errors. Simulation results in a hands-free talk scenario demonstrate that the proposed echo canceller achieves robust echo cancellation even in severe double-talk periods.