Acoustic echo suppression

A method for controlling an echo suppressor configured to suppress a residual echo of a far-end signal included in a primary error signal received from an echo canceller, the echo canceller being configured to cancel a primary echo estimate from a microphone signal so as to form the primary error signal, the primary echo estimate being formed at a primary adaptive filter and representing an estimate of the far-end signal comprised in the microphone signal, the method comprising:

• forming a first measure of coherence between the microphone signal and the primary error signal, and a second measure of coherence between the microphone signal and the primary echo estimate;
• if the primary adaptive filter is determined to be in a converged state, combining the first and second measures of coherence so as to form one or more first steady state decision parameters indicative of a state of the microphone signal;
• and
• controlling activation of the echo suppressor in dependence on the one or more first steady state decision parameters.

A controller for an echo suppressor configured to suppress a residual echo of a far-end signal included in a primary error signal, the controller adapted for operation with a primary adaptive filter configured to form a primary echo estimate of the far-end signal included in a microphone signal and with an echo canceller configured to cancel that primary echo estimate from the microphone signal so as to form the primary error signal, the controller comprising:

• a secondary adaptive filter configured to form a secondary echo estimate of the far-end signal included in the microphone signal;
• a coherence estimator configured to form a first measure of coherence between the microphone signal and the primary error signal, and a second measure of coherence between the microphone signal and the primary echo estimate;
• and
• control logic configured to, when the primary adaptive filter is in a non-converged state, combine the microphone signal and the secondary echo estimate so as to form a transient decision parameter indicative of a state of the microphone signal and, in dependence on the transient decision parameter, control activation of the echo suppressor.

A method for controlling an echo suppressor configured to suppress a residual echo of a far-end signal included in a primary error signal received from an echo canceller, the echo canceller being configured to cancel a primary echo estimate from a microphone signal so as to form the primary error signal, the primary echo estimate being formed at a primary adaptive filter and representing an estimate of the far-end signal comprised in the microphone signal, the method comprising:

• at a secondary adaptive filter, forming a secondary echo estimate of the far-end signal comprised in the microphone signal;
• forming a first measure of coherence between the microphone signal and the primary error signal, and a second measure of coherence between the microphone signal and the primary echo estimate;
• if the primary adaptive filter is determined to be in a non-converged state, combining the microphone signal and the secondary echo estimate so as to form a transient decision parameter indicative of a state of the microphone signal;
• and
• controlling activation of the echo suppressor in dependence on the transient decision parameter.