Patent ID: 6975722

Claim:
An echo canceller comprising: a receive path having a receive input and a receive output; a send path having a send input and a send output; a first non-adaptive filter for generating a first echo estimation signal; a second segmented adaptive filter for generating a second echo estimation signal; a first subtractor for receiving a send signal from said send path input and for receiving said first echo estimation signal and for generating a first compensated send signal; a second subtractor for receiving said send signal from said send path input and for receiving said second echo estimation signal and generating a second compensated send signal, having an output for providing said second compensated signal to said send path; a means to determine whether a sum of squared reflection coefficients of individual segments of said segmented adaptive filter is greater than −40 dB in said segmented adaptive filter, and for selecting only those coefficients to be used in coefficient generation for said non-adapative filter; and a controller connected to said send path for receiving said second compensated send signal and to said first subtractor for receiving said first compensated send signal wherein said controller initiates a non-iterative least squares estimate for said coefficients of said first non-adaptive filter segments corresponding to said selected segments from said adaptive filter, if: said short term send out energy is greater than or equal to a first fixed threshold, a ratio of said corresponding short term send in energy to the short term send out energy is less than or equal to a second threshold, and a short term receive out energy is greater than or equal to said corresponding short term, send in energy plus 6 dB.