Patent ID: 7333605

Claim:
An acoustic echo canceller comprising: an adaptive filter operative to receive a reference signal and a near-end signal, derive an estimate of echo in the near-end signal using a digital filter, and cancel the echo estimate from the near-end signal to provide an output signal; a step size control unit operative to receive the reference and output signals and provide a step size signal indicative of one or more step sizes to be used to adjust coefficients of the digital filter, wherein the one or more step sizes are determined based on the coefficients, characteristics of the reference and output signals; and a stability control unit operative to receive initial adjustments for the coefficients of the digital filter and provide modified adjustments, and wherein the coefficients are updated based on the modified adjustments; and wherein the step size is determined by the following equations: u ′ ⁡ ( n ) = c 1 ⁢ P r ⁡ ( n ) · v ⁡ ( n ) P y ⁡ ( n ) where u′(n) is the step size; P r (n) is the average power of the reference signal; P y (n) is the average power of the output signal; c 1 is a scaling factor; and wherein a first combiner receives and combines the power P W b (n) of the coefficients in the back segment with the average difference power P adW f (n) of the coefficients in the front segment to obtain a signal v(n).