Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that echo estimate from a microphone signal to output an echo cancelled signal, the gain control system comprising a monitoring unit configured to estimate an energy associated with an impulse response of an adaptive filter configured to generate the echo estimate from the far-end signal and a gain tuner configured to adjust an attenuation of at least one of the microphone signal and the far-end signal in dependence on the estimated energy.

Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that echo estimate from a microphone signal to output an echo cancelled signal, the gain control system comprising a monitoring unit configured to estimate an energy associated with an impulse response of an adaptive filter configured to generate the echo estimate from the far-end signal and a gain tuner configured to adjust an attenuation of at least one of the microphone signal and the far-end signal in dependence on the estimated energy.

Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that echo estimate from a microphone signal to output an echo cancelled signal, the gain control system comprising a monitoring unit configured to estimate an energy associated with an impulse response of an adaptive filter configured to generate the echo estimate from the far-end signal and a gain tuner configured to adjust an attenuation of at least one of the microphone signal and the far-end signal in dependence on the estimated energy.

Abstract: 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 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 comprised in the microphone signal; and control logic operable in at least two modes selected in dependence on a convergence state of the primary adaptive filter, the control logic being configured to control activation of the echo suppressor in dependence one or more transient or steady state decision parameters.

Abstract: A nearend speech detector for classifying speech at a communication system receiving a microphone signal from a nearend microphone and a farend signal from a farend communication system, the nearend speech detector comprising: a signal processor configured to transform the microphone and farend signals into the frequency domain; a calculation unit configured to form: an estimate of a nearend signal representing nearend speech present in the microphone signal; and a measure of gain between the microphone signal and the nearend signal; and a signal classifier configured to classify speech at the communication system in dependence on a measure of variance of the gain and a measure of variance of the nearend signal.

Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that estimate from a microphone signal to output an echo cancelled signal, the system comprising an echo measurement unit configured to calculate a ratio of the microphone signal to the far-end signal, an attenuation unit configured to attenuate at least one of the microphone signal and the far-end signal to output a second microphone signal and a second far-end signal to the echo canceller, the ratio of the second microphone signal to the second far-end signal being different from the calculated ratio, and an attenuation controller configured to control the attenuation unit, in dependence on the calculated ratio, so as to alter the ratio of the second microphone signal to the second far-end signal and control the echo-cancelled signal.

Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that echo estimate from a microphone signal to output an echo cancelled signal, the gain control system comprising a monitoring unit configured to estimate an energy associated with an impulse response of an adaptive filter configured to generate the echo estimate from the far-end signal and a gain tuner configured to adjust an attenuation of at least one of the microphone signal and the far-end signal in dependence on the estimated energy.

Abstract: A threshold control system for controlling a non-linear processor in an echo canceller, the non-linear processor being configured to remove any signal energy below a threshold that remains in a microphone signal after the echo canceller has subtracted an echo estimate from it, the threshold control system comprising a convergence unit configured to determine an indication of the stability of an adaptive filter, the adaptive filter being configured to continuously model an echo path so as to generate the echo estimate, and a threshold tuner configured to adjust the threshold of the non-linear processor in dependence on the indication.

Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that estimate from a microphone signal to output an echo cancelled signal, the system comprising an echo measurement unit configured to calculate a ratio of the microphone signal to the far-end signal, an attenuation unit configured to attenuate at least one of the microphone signal and the far-end signal to output a second microphone signal and a second far-end signal to the echo canceller, the ratio of the second microphone signal to the second far-end signal being different from the calculated ratio, and an attenuation controller configured to control the attenuation unit, in dependence on the calculated ratio, so as to alter the ratio of the second microphone signal to the second far-end signal and control the echo-cancelled signal.

Abstract: 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 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 comprised in the microphone signal; and control logic operable in at least two modes selected in dependence on a convergence state of the primary adaptive filter, the control logic being configured to control activation of the echo suppressor in dependence one or more transient or steady state decision parameters.

Abstract: A nearend speech detector for classifying speech at a communication system receiving a microphone signal from a nearend microphone and a farend signal from a farend communication system, the nearend speech detector comprising: a signal processor configured to transform the microphone and farend signals into the frequency domain; a calculation unit configured to form: an estimate of a nearend signal representing nearend speech present in the microphone signal; and a measure of gain between the microphone signal and the nearend signal; and a signal classifier configured to classify speech at the communication system in dependence on a measure of variance of the gain and a measure of variance of the nearend signal.

Abstract: 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 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 comprised in the microphone signal; and control logic operable in at least two modes selected in dependence on a convergence state of the primary adaptive filter, the control logic being configured to control activation of the echo suppressor in dependence one or more transient or steady state decision parameters.

Abstract: In an example, time and frequency domain speech enhancement is implemented on a platform having a programmable device, such a PC or a smartphone running an OS. Echo cancellation is done first in time domain to cancel a dominant portion of the echo. Residual echo is cancelled jointly with noise reduction during a subsequent frequency domain stage. The time domain block uses a dual band, shorter length Adaptive Filter for faster convergence. Non-linear residual echo is cancelled based on an echo estimate and an error signal from the adaptive filters. A controller locates regions that had residual echo suppressed and which do not have speech and injects comfort noise. The controller can be full-duplex and operate non-linearly. An AGC selectively amplifies the frequency bins, based on the Gain function used by the residual echo and noise canceller.

Abstract: 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 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 comprised in the microphone signal; and control logic operable in at least two modes selected in dependence on a convergence state of the primary adaptive filter, the control logic being configured to control activation of the echo suppressor in dependence one or more transient or steady state decision parameters.

Abstract: In an example, time and frequency domain speech enhancement is implemented on a platform having a programmable device, such a PC or a smartphone running an OS. Echo cancellation is done first in time domain to cancel a dominant portion of the echo. Residual echo is cancelled jointly with noise reduction during a subsequent frequency domain stage. The time domain block uses a dual band, shorter length Adaptive Filter for faster convergence. Non-linear residual echo is cancelled based on an echo estimate and an error signal from the adaptive filters. A controller locates regions that had residual echo suppressed and which do not have speech and injects comfort noise. The controller can be full-duplex and operate non-linearly. An AGC selectively amplifies the frequency bins, based on the Gain function used by the residual echo and noise canceller.

Abstract: A threshold control system for controlling a non-linear processor in an echo canceller, the non-linear processor being configured to remove any signal energy below a threshold that remains in a microphone signal after the echo canceller has subtracted an echo estimate from it, the threshold control system comprising a convergence unit configured to determine an indication of the stability of an adaptive filter, the adaptive filter being configured to continuously model an echo path so as to generate the echo estimate, and a threshold tuner configured to adjust the threshold of the non-linear processor in dependence on the indication.

Abstract: A gain control system for dynamically tuning an echo canceller, the echo canceller being configured to estimate an echo of a far-end signal and subtract that estimate from a microphone signal to output an echo cancelled signal, the system comprising an echo measurement unit configured to calculate a ratio of the microphone signal to the far-end signal, an attenuation unit configured to attenuate at least one of the microphone signal and the far-end signal to output a second microphone signal and a second far-end signal to the echo canceller, the ratio of the second microphone signal to the second far-end signal being different from the calculated ratio, and an attenuation controller configured to control the attenuation unit, in dependence on the calculated ratio, so as to alter the ratio of the second microphone signal to the second far-end signal and control the echo-cancelled signal.

Abstract: 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 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 comprised in the microphone signal; and control logic operable in at least two modes selected in dependence on a convergence state of the primary adaptive filter, the control logic being configured to control activation of the echo suppressor in dependence one or more transient or steady state decision parameters.

Abstract: In an example, time and frequency domain speech enhancement is implemented on a platform having a programmable device, such a PC or a smartphone running an OS. Echo cancellation is done first in time domain to cancel a dominant portion of the echo. Residual echo is cancelled jointly with noise reduction during a subsequent frequency domain stage. The time domain block uses a dual band, shorter length Adaptive Filter for faster convergence. Non-linear residual echo is cancelled based on an echo estimate and an error signal from the adaptive filters. A controller locates regions that had residual echo suppressed and which do not have speech and injects comfort noise. The controller can be full-duplex and operate non-linearly. An AGC selectively amplifies the frequency bins, based on the Gain function used by the residual echo and noise canceller.

Abstract: 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 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 comprised in the microphone signal; and control logic operable in at least two modes selected in dependence on a convergence state of the primary adaptive filter, the control logic being configured to control activation of the echo suppressor in dependence one or more transient or steady state decision parameters.