Abstract: In accordance with one aspect, a device is provided having a transducer comprising a conductor, a diaphragm configured to move relative to the conductor, and a reference volume in communication with the external environment. The diaphragm separates the reference volume and the external environment. The device further includes a controller operably coupled to the transducer and configured to determine an air pressure of an external environment based at least in part on movement of the diaphragm.

Abstract: A communication system and method is disclosed. The system and method provides for acoustic echo cancellation. For instance, a processor implements a non-linear loudspeaker model to approximate loudspeaker performance. Using the model, a cancellation signal may be generated to ameliorate cross-talk between a loudspeaker and microphone to diminish an echo.

Abstract: Various methods, systems, and apparatus are disclosed with improved imposter rejection for keyword recognition systems in a wearable device. Speech signals are measured by a microphone and a vibration sensor, the vibration sensor configured to measure vibrations in the body of a wearer of the device. An audio signal from the microphone and a vibration signal from the vibration sensor are input into a classifier to determine whether the wearer of the device spoke the keyword. In some embodiments, high-frequency components of a signal from the microphone may be combined with low-frequency components of a signal from the vibration sensor to generate a combined speech signal. The classifier may use a classification model trained with positive training data of the wearer speaking the keyword and negative training data of a non-wearer speaking the keyword.

Abstract: In accordance with one aspect, a device is provided having a transducer comprising a conductor, a diaphragm configured to move relative to the conductor, and a reference volume in communication with the external environment. The diaphragm separates the reference volume and the external environment. The device further includes a controller operably coupled to the transducer and configured to determine an air pressure of an external environment based at least in part on movement of the diaphragm.

Abstract: Methods and systems specifically designed to reduce loudspeaker distortion by reducing voice coil excursion are provided. An input audio signal is processed based on a specific linear model of a loudspeaker, and a dynamic filter is generated and applied to this audio signal. The filter changes the relative phases of the spectral components of the input signal to reduce estimated excursion peaks. The quality of the audio signal is not diminished in comparison to traditional filter approaches. The processing of the input signal may involve determining a main frequency which may be used to determine the fundamental frequency. Multiples of the fundamental frequencies provide harmonic frequencies. The phases of all the harmonic frequencies, including the fundamental, may be measured and compared to a target vector of phases. The difference between the measured phases and the target phases may then be used to calculate the poles and zeros and corresponding filter coefficients.