Abstract: The technology relates to establishing wireless communication links, or connections, between a first audio accessory device, a second audio accessory device, and a client computing device. After receiving signals from the client computing device to initiate audio output, the first audio accessory device and the second audio accessory device may both perform a series of steps in parallel to establish connections with the client computing device and with each other. The series of steps may include relaying one or more acknowledgement (ACK) signals between the audio accessory devices in order to confirm proper receipt of the signals from the client computing device at both audio accessory devices. Alternatively, the series of steps may include transmitting a jamming signal from one of the audio accessory devices in order to prevent an ACK signal from the other audio accessory device from reaching the client computing device and initiating audio output.

Abstract: The technology relates to establishing wireless communication links, or connections, between a first audio accessory device, a second audio accessory device, and a client computing device. After receiving signals from the client computing device to initiate audio output, the first audio accessory device and the second audio accessory device may both perform a series of steps in parallel to establish connections with the client computing device and with each other. The series of steps may include relaying one or more acknowledgement (ACK) signals between the audio accessory devices in order to confirm proper receipt of the signals from the client computing device at both audio accessory devices. Alternatively, the series of steps may include transmitting a jamming signal from one of the audio accessory devices in order to prevent an ACK signal from the other audio accessory device from reaching the client computing device and initiating audio output.

Abstract: The technology relates to establishing wireless communication links, or connections, between a first audio accessory device, a second audio accessory device, and a client computing device. After receiving signals from the client computing device to initiate audio output, the first audio accessory device and the second audio accessory device may both perform a series of steps in parallel to establish connections with the client computing device and with each other. The series of steps may include relaying one or more acknowledgement (ACK) signals between the audio accessory devices in order to confirm proper receipt of the signals from the client computing device at both audio accessory devices. Alternatively, the series of steps may include transmitting a jamming signal from one of the audio accessory devices in order to prevent an ACK signal from the other audio accessory device from reaching the client computing device and initiating audio output.

Abstract: The technology relates to establishing wireless communication links, or connections, between a first audio accessory device, a second audio accessory device, and a client computing device. After receiving signals from the client computing device to initiate audio output, the first audio accessory device and the second audio accessory device may both perform a series of steps in parallel to establish connections with the client computing device and with each other. The series of steps may include relaying one or more acknowledgement (ACK) signals between the audio accessory devices in order to confirm proper receipt of the signals from the client computing device at both audio accessory devices. Alternatively, the series of steps may include transmitting a jamming signal from one of the audio accessory devices in order to prevent an ACK signal from the other audio accessory device from reaching the client computing device and initiating audio output.

Abstract: Various of the disclosed embodiments improve encoding during a network call, such as a Voice Over Internet Protocol (VOIP) connection, by correlating various contextual parameters from previous calls, with appropriate settings for a current call. For example, the system may take note of the model of cell phone used during a communication, the carrier, the presence of a WiFi connection, the user rating, the codecs employed, etc. During a subsequent call, the system may compare these past calling parameters with the current situation, and may select call settings (e.g., codec selections) based thereon. Machine learning methods may be applied using the past data to inform the selection of the settings for the present call.

Abstract: Features are disclosed for generating comfort noise that matches a frequency spectrum of original background noise. For example, a spectral shape of an estimated noise component can be determined. A frame of white noise can be modified based at least in part on the spectral shape of the noise component. The modified frame of white noise can be converted to a time-domain noise signal. The level of the time-domain noise signal can be adjusted to match an original level of the noise after noise reduction. Residual echo suppression can sometimes cause background noise to be eliminated, causing silence. The adjusted time-domain noise signal can be added after residual echo suppression to maintain continuity of background noise levels.

Abstract: A step size controller may be used to control the rate of adaptation in an acoustic echo canceller. Step size control based on the values of adaptive coefficients (rather than, e.g., a fixed initial adaptation period) provides improved reliability and resistance to disruption. Accordingly, features are disclosed for controlling step size based on the values of adaptive coefficients.

Abstract: A technique for detecting in-band signaling tones in a communication system includes performing a first adaptation of an adaptive filter of an echo canceller in response to detection of a far-end harmonic signal. In this case, the adaptive filter provides an echo estimation signal. The technique also includes subtracting the echo estimation signal from a near-end signal that includes one or more in-band signaling tones to provide an error signal. The technique further includes detecting, using a tone detector, the one or more in-band signaling tones in the error signal.

Abstract: A technique for updating filter coefficients of an adaptive filter includes filtering a signal with an adaptive filter, whose filter coefficients are grouped into filter blocks. In this case a number of the filter blocks is less than or equal to a number of the filter coefficients. During each update period, the filter coefficients for less than all of the filter blocks are updated based on a network echo path impulse response.

Abstract: In one or more embodiments, an echo reduction system can include multiple adaptive filters operable to provide estimated echo replicas based on received signal information coupled to respective multiple adders that can combine a send signal and outputs of the respective adaptive filters and can provide respective output combinations to a filter selector. The filter selector can select from the outputs of the adders and provide a selected output as output for the echo reduction system. In one or more embodiments, the filter selector can control signal processing of the filters by providing control signal to the adaptive filters, where the control signals can indicate to ones of the adaptive filters to pause or continue signal processing. In one or more embodiments, the echo reduction system can include at least one delay unit that can delay receive signal information to at least one of the adaptive filters.

Abstract: Methods and corresponding systems in an adaptive filter include calculating a signal estimator output using filter coefficients, and calculating an error signal. Next, a coefficient threshold is determined. Thereafter, for each filter coefficient, a first step size is assigned to filter coefficients with a magnitude less than the coefficient threshold, and a second step size is assigned to filter coefficients with a magnitude greater than or equal to the coefficient threshold. Finally, the filter coefficients are updated using the first and second step sizes and the error signal. The coefficient threshold can be selected as the average of the magnitudes of the filter coefficients. Alternatively, the coefficient threshold can be selected as the Mth largest of the filter coefficients ranked in order of magnitude. In one embodiment, the first step size can be less than one and the second step size can be greater than one.

Abstract: In a data processing system, a method includes receiving samples of a send path input signal (Sin) and samples of a receive path input signal (Rin); in response to receiving each sample of the send path input signal, providing a double-talk indicator to indicate whether or not double-talk has been detected; using the double-talk indicator to determine a double-talk density within a predetermined number of samples of the send path input signal or the receive path input signal; and using the double-talk density to provide a heavy double-talk indicator which indicates whether or not heavy double-talk has been detected. In response to the heavy double-talk indicator indicating that heavy double-talk has been detected, a heavy double-talk mode may be entered.

Abstract: A technique for detecting in-band signaling tones in a communication system includes performing a first adaptation of an adaptive filter of an echo canceller in response to detection of a far-end harmonic signal. In this case, the adaptive filter provides an echo estimation signal. The technique also includes subtracting the echo estimation signal from a near-end signal that includes one or more in-band signaling tones to provide an error signal. The technique further includes detecting, using a tone detector, the one or more in-band signaling tones in the error signal.

Abstract: A technique for updating filter coefficients of an adaptive filter includes filtering a signal with an adaptive filter, whose filter coefficients are grouped into filter blocks. In this case a number of the filter blocks is less than or equal to a number of the filter coefficients. During each update period, the filter coefficients for less than all of the filter blocks are updated based on a network echo path impulse response.

Abstract: In one or more embodiments, an echo reduction system can include multiple adaptive filters operable to provide estimated echo replicas based on received signal information coupled to respective multiple adders that can combine a send signal and outputs of the respective adaptive filters and can provide respective output combinations to a filter selector. The filter selector can select from the outputs of the adders and provide a selected output as output for the echo reduction system. In one or more embodiments, the filter selector can control signal processing of the filters by providing control signal to the adaptive filters, where the control signals can indicate to ones of the adaptive filters to pause or continue signal processing. In one or more embodiments, the echo reduction system can include at least one delay unit that can delay receive signal information to at least one of the adaptive filters.

Abstract: A system includes receive and send inputs, an adaptive filter, a combiner, a non-linear processor, and a tone detector. The receive input receives a first signal having first voice and first tone information. The send input receives a second signal having echo information, second tone information, and second voice information. The adaptive filter has an input coupled to the receive input, and an output. The combiner has a first input coupled to the send input, a second input coupled to the output of the adaptive filter, and an output providing an intermediate signal. The nonlinear processor has an input coupled to the output of the combiner and an output for providing an output signal for obtaining the second voice. The tone detector is coupled to the output of the combiner and detects the second tone in the intermediate signal prior to the intermediate signal being processed by the nonlinear processor.

Abstract: In a data processing system, a method includes receiving samples of a send path input signal (Sin) and samples of a receive path input signal (Rin); in response to receiving each sample of the send path input signal, providing a double-talk indicator to indicate whether or not double-talk has been detected; using the double-talk indicator to determine a double-talk density within a predetermined number of samples of the send path input signal or the receive path input signal; and using the double-talk density to provide a heavy double-talk indicator which indicates whether or not heavy double-talk has been detected. In response to the heavy double-talk indicator indicating that heavy double-talk has been detected, a heavy double-talk mode may be entered.

Abstract: Methods and corresponding systems in an adaptive filter include calculating a signal estimator output using filter coefficients, and calculating an error signal. Next, a coefficient threshold is determined. Thereafter, for each filter coefficient, a first step size is assigned to filter coefficients with a magnitude less than the coefficient threshold, and a second step size is assigned to filter coefficients with a magnitude greater than or equal to the coefficient threshold. Finally, the filter coefficients are updated using the first and second step sizes and the error signal. The coefficient threshold can be selected as the average of the magnitudes of the filter coefficients. Alternatively, the coefficient threshold can be selected as the Mth largest of the filter coefficients ranked in order of magnitude. In one embodiment, the first step size can be less than one and the second step size can be greater than one.