Patent attributes
Canceling acoustic echoes includes picking up with a microphone sound generated by a sound source and transferred from the sound source to the microphone via an unknown transfer path having an unknown transfer function, and providing an electrical microphone signal therefrom. It further includes approximating the unknown transfer function with an estimated transfer function of an adaptive filter and filtering an electrical signal representative of the sound generated by the sound source with the estimated transfer function to provide an estimated signal therefrom, the adaptive filter having an adaptive adaptation step size. It further includes filtering a difference signal, which is the difference between the microphone signal and the estimated signal, with a post filter transfer function of an adaptive post filter. The post filter transfer function is the difference between one and the adaptive adaptation step size, and the adaptive post filter is configured to have a minimum damping, the minimum damping being limited to a minimum threshold.
