Patent ID: 7221755
Filing Date: 2007-05-22
Classification: H04M

Abstract:
1. A method of operating an echo canceller which receives a reference signal and converges to an estimated echo signal of a received input signal via feedback of an error signal, said echo canceller being characterized by predetermined filter coefficients when converged, said method comprising the steps of: a) detecting power levels of said received input signal and said error signal; b) calculating an Echo Return Loss Enhancement value based on said power levels of said received input signal and said error signal, wherein said Echo Return Loss Enhancement value is expressed in decibels as c) in the event said Echo Return Loss Enhancement value exceeds a threshold then storing said predetermined filter coefficients for subsequent use by said echo canceller, increasing said threshold by a predetermined factor and re-executing steps a) to c), and if said Echo Return Loss Enhancement value does not exceed the threshold, determining whether voice is present in said input signal and if so reducing said threshold by a predetermined factor and re-executing steps a) to c).