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US 9,426,279 B2Granted
Systems and methods for echo cancellation and echo suppression
AssigneeConexant Systems, Inc.
InventorsYouhong Lu, Trausti Thormundsson, Yair Kerner, Ragnar H. Jonsson
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Abstract
Traditionally, echo cancellation has employed linear adaptive filters to cancel echoes in a two way communication system. The rate of adaptation is often dynamic and varies over time. Disclosed are novel rates of adaptation that perform well in the presence of background noise, during double talk and with echo path changes. Additionally, the echo or residual echo can further be suppressed with non-linear processing performed using joint frequency-time domain processing.
Claims13
A method of cancelling an echo comprising:
- approximating the echo by applying a transfer function to a far-end signal to generate an approximate echo, said transfer function having an impulse response and an order;
- adapting the transfer function by modifying the impulse response based on an adaptation coefficient, by dividing a value generated by an estimator function by a sum of a total energy of the far-end signal over a first observation window and a predetermined constant number;
- and wherein the estimator function generates a value on the basis of the received signal, an output signal from an echo canceller, the far-end signal and/or the approximate echo.
A system with echo cancellation comprising:
- an echo approximator configured to apply a transfer function, having an impulse response and an order, to a far-end signal and produce an approximate echo;
- a subtractor configured to subtract the approximate echo from a received signal comprising a near-end signal and an echo of the far-end signal to produce an output signal;
- an adaption coefficient generator configured to generate an adaptation coefficient, by dividing a value generated by an estimator by a sum of a total energy of the far-end signal over a first observation window and a predetermined constant number;
- wherein the impulse response of the transfer function is modified based on the adaptation coefficient.
1 more element
Dependencies are inferred from the claim text.