Acoustic echo control for high quality audio teleconferencing

The authors describe an acoustic echo control system offering high-quality audio teleconferencing. A novel type of acoustic echo control combining linear echo cancelling with nonlinear harmonic processing is proposed. Using a signal decorrelation algorithm and subband echo canceller, convergence properties faster than those of the normalized least mean square algorithm for colored signals have been obtained, and a large-tap-length FIR (finite impulse response) echo canceller has been implemented. Experimental prototype hardware has been realized and examined in a real acoustic field. Excellent echo cancellation and fast convergence properties have been obtained. Good howling protection characteristics and robust properties for howling protection under acoustic echo path variations have been confirmed