Patent ID: 8275142

Claim:
An acoustic echo cancellation system, comprising: a first echo cancellation unit, comprising: a first attenuator, having a first down-scaling factor, for attenuating a first signal; a first filter to generate a first echo signal estimate based on the attenuated first signal; and a first subtractor to generate a third signal by subtracting the first echo signal estimate from a second signal; a second echo cancellation unit, comprising: a second attenuator, having a second down-scaling factor, for attenuating the first signal; and a second filter to generate a second echo signal estimate based on the output signal of the second attenuator, wherein the second down-scaling factor is different from the first down-scaling factor; and a second subtractor to generate a fourth signal by subtracting the second echo signal estimate from the third signal; a third filter to generate a third echo signal estimate based on the first signal; and a third subtractor subtracting the third echo signal estimate from the fourth third signal.