Patent ID: 7386120

Claim:
A method for determining the location of an active region of an echo path, comprising: acquiring a first plurality of far-end signals R IN (n); acquiring a second, corresponding, plurality of near-end signals S IN (n); pre-emphasis filtering the first plurality of far-end signals Rin(n) and the corresponding plurality of near-end signals Sin(n); reducing the range of input levels of the filtered signals by bringing the first plurality of filtered far-end signals R IN (n) and the second plurality of filtered near-end signals S IN (n) to uniform levels: generating a set of frequency domain coefficients from the reduced input level range acquired signals, each one of the generated frequency domain coefficients describing a filter which covers a respective portion of the echo path; determining at least one time domain energy estimate from the generated set of frequency domain coefficients; and estimating the location of the active region of the echo path from the at least one time domain energy estimate determined from the generated set of frequency domain coefficients.