Abstract: A hearing device such as a hearing aid, ear pod, headphone, or other wearable is provided, whose components include the following: an acoustic transducer with a vent port operable to produce sound, a housing of the acoustic transducer with a sound opening, and an actuatable acoustic valve disposed in the housing, where the acoustic valve is actuatable to alter passage of sound through the acoustic vent to change the state of the hearing device between an open vent state and a closed vent state, so that actuation of the valve changes an acoustic characteristic of the hearing device.

Abstract: A method for echo cancellation based on microphone signal correlation is disclosed.

Abstract: Acoustic valves include a housing having an acoustic inlet, an acoustic outlet, and an acoustic passage between the inlet and the outlet. An electrical coil is disposed in the housing and configured to generate a magnetic field when energized by an actuation signal. A spring is coupled to an armature movably disposed in the housing between a first surface and a second surface. The valve has a first stable state wherein the armature is positioned against one surface when the electrical coil is not energized, and the valve has a second stable state wherein the armature is positioned against the other surface when the electrical coil is not energized. The armature is movable between the first and second states when the electrical coil is energized, wherein the acoustic passage is more obstructed when the armature is in one state than when the armature is in the other state.

Abstract: Acoustic valves including a housing having an acoustic passage are disclosed. A bobbin located in the housing includes a valve seat and a body member housing a magnetic core. An electrical coil is disposed about a portion of the body member, an axial dimension of the electrical coil substantially aligned with an axial dimension of the magnetic core. The electrical coil generates a magnetic field when energized. An armature is movably disposed in the housing between the valve seat and a second surface of the acoustic valve. The valve has a first stable state when the armature is positioned against the valve seat, and the valve has a second stable state when the armature is positioned against the second surface. The valve seat and the second surface are on opposite sides of the armature.

Abstract: An integrated circuit for processing audio signals from a microphone assembly, combinations thereof and methods therefor, including a multi-issue processor configured to execute multiple instructions concurrently and connectable to a memory with a plurality of locations each represented by a corresponding index. Bit-reversal is performed on a sequence of audio data bits stored in memory by concurrently performing a load or store operation related to a first index and determining whether to perform a load operation for a second index.

Abstract: Microphones including a housing defining a cavity, a plurality of conductors positioned within the cavity, at least one dielectric bar positioned within the cavity, and a transducer diaphragm. The conductors are structured to move in response to pressure changes while the housing remains fixed. A first conductor generates first electrical signals responsive to the pressure changes resulting from changes in an atmospheric pressure. A second conductor generates second electrical signals responsive to the pressure changes resulting from acoustic activity. The dielectric bar is fixed with respect to the cavity and remains fixed under the pressure changes. The dielectric bar is adjacent to at least one of the conductors. In response to an applied pressure that is an atmospheric pressure and/or an acoustic pressure, the transducer diaphragm exerts a force on the housing and displaces at least a portion of conductors with respect to the dielectric bar.

Abstract: A microphone assembly includes an acoustic filter with a first highpass cut-off frequency. The microphone assembly additionally includes a forward signal path and a feedback signal path. The forward signal path is configured to amplify or buffer an electrical signal generated by a transducer in response to sound and to convert the electrical signal to a digital signal. The feedback signal path is configured to generate a digital control signal based on the digital signal and to generate and output a sequence of variable current pulses based on the digital control signal. The variable current pulses suppress frequencies of the electrical signal below a second highpass cut-off frequency, higher than the first highpass cut-off frequency.

Abstract: A microphone assembly comprises a substrate and an enclosure disposed on the substrate. A port is defined in one of the substrate or the enclosure. An acoustic transducer is configured to generate an electrical signal in response to acoustic activity. The acoustic transducer comprises a membrane separating a front volume from a back volume of the microphone assembly. The front volume is in fluidic communication with the port, and the back volume is filled with a first gas having a thermal conductivity lower than a thermal conductivity of air. An integrated circuit is electrically coupled to the acoustic transducer and configured to receive the electrical signal from the acoustic transducer. At least a portion of a boundary defining at least one of the front volume or the back volume is configured to have compliance so as to allow pressure equalization. The first gas is different from the second gas.

Abstract: A microphone assembly includes an acoustic transducer and an audio signal electrical circuit configured to receive an output signal from the acoustic transducer. The output signal includes an audio signal component and a tracking signal component. The audio signal component is representative of an acoustic signal detected by the acoustic transducer and the tracking signal component is based on an input tracking signal applied to the acoustic transducer. The audio signal electrical circuit includes an analog to digital converter configured to convert the output signal into a digital signal, an extraction circuit configured to separate the tracking signal component and the audio signal component from the digital signal, an envelope estimation circuit configured to estimate a tracking signal envelope from the tracking signal component, and a signal correction circuit configured to reduce distortion in the audio signal component using the tracking signal envelope.

Abstract: An acoustic apparatus includes a back plate, a diaphragm, and at least one pillar. The diaphragm and the back plate are disposed in spaced relation to each other. At least one pillar is configured to at least temporarily connect the back plate and the diaphragm across the distance. The diaphragm stiffness is increased as compared to a diaphragm stiffness in absence of the pillar. The at least one pillar provides a clamped boundary condition when the diaphragm is electrically biased and the clamped boundary is provided at locations where the diaphragm is supported by the at least one pillar.

Abstract: A microphone assembly includes a transducer element and a processing circuit. The processing circuit includes an analog-to-digital converter (ADC) configured to receive, sample and quantize a microphone signal generated by the transducer element to generate a corresponding digital microphone signal. The processing circuit includes a feedback path including a digital loop filter configured to receive and filter the digital microphone signal to provide a first digital feedback signal and a digital-to-analog converter (DAC) configured to convert the first digital feedback signal into a corresponding analog feedback signal. The processing circuit additionally includes a summing node at the transducer output configured to combine the microphone signal and the analog feedback signal.

Abstract: A method of forming an acoustic transducer comprises providing a substrate and depositing a first structural layer on the substrate. The first structural layer is selectively etched to form at least one of an enclosed trench or an enclosed pillar thereon. A second structural layer is deposited on the first structural layer and includes a depression or a bump corresponding to the enclosed trench or pillar, respectively. At least the second structural layer is heated to a temperature above a glass transition temperature of the second structural layer causing the second structural layer to reflow. A diaphragm layer is deposited on the second structural layer such that the diaphragm layer includes at least one of a downward facing corrugation corresponding to the depression or an upward facing corrugation corresponding to the bump. The diaphragm layer is released, thereby forming a diaphragm suspended over the substrate.

Abstract: Methods and apparatus determine the actual state of one or more acoustic valves e.g., whether an acoustic valve is open or closed, in a hearing device. A sensor in the hearing device is configured to generate an output signal indicative of a state of the acoustic valve. An electrical circuit actuates the acoustic valve if the actual state is different than a desired state. The determination of the state of the acoustic valve can be done on the hearing device or on a remote device.

Abstract: A digital microphone device includes circuitry that can reduce the risk of noise caused due to an idle tone frequency component in a digital signal output by the digital microphone device. In stereo mode and other applications where interference occurs between two or more such microphones, each microphone device includes a digital output having a corresponding idle tone frequency, one of which is offset to shift noise components outside of a desired frequency range.

Abstract: An acoustic device including a motor disposed in a housing having a non-porous elastomeric membrane disposed across an acoustic path defined by a sound port of the housing is disclosed. The motor may be embodied as MEMS transducer configured to generate an electrical signal responsive to an acoustic signal, or as some other electromechanical device. The membrane has a compliance that is 1 to 100 times a compliance of the acoustic device without the membrane, wherein the membrane prevents ingress of contaminants (e.g., solids, liquids or light) via the sound port while permitting propagation of the acoustic signal along the acoustic path without significant loss.

Abstract: A microphone assembly comprises a substrate and an enclosure disposed on the substrate. A port is defined in one of the substrate or the enclosure. An acoustic transducer is configured to generate an electrical signal in response to acoustic activity. The acoustic transducer comprises a membrane separating a front volume from a back volume of the microphone assembly. The front volume is in fluidic communication with the port, and the back volume is filled with a first gas having a thermal conductivity lower than a thermal conductivity of air. An integrated circuit is electrically coupled to the acoustic transducer and configured to receive the electrical signal from the acoustic transducer. At least a portion of a boundary defining at least one of the front volume or the back volume is configured to have compliance so as to allow pressure equalization. The first gas is different from the second gas.

Abstract: Disclosed herein include a system and a method of synchronizing a slave device to a signal from a master device based on pulse width analysis. The pulse width analysis is a process to sample the signal at a sampling frequency of the slave device, determine varying pulse widths of the sampled signal, and determine frequency of an embedded master clock signal of the signal based on statistical analysis of the varying pulse widths. Advantageously, performing pulse width analysis allows synchronization of a slave device with the embedded master clock signal in a time and cost efficient manner. In one aspect, determining a frequency of the embedded master clock signal and adjusting an internal clock of the slave device according to the determined frequency is faster and more cost efficient than iteratively adjusting the internal clock based on feedback loop based circuitries.

Abstract: A multi-core audio processor includes an audio fabric block configured to organize data received from a plurality of audio interfaces into streams for processing by a plurality of digital signal processing cores. The plurality of digital signal processing cores include a single sample processing core and a frame processing core. The multi-core audio processor also includes a pool of undedicated random access memory (RAM) and a main controller configured to dynamically allocate memory resources from the pool of undedicated RAM amongst one or more of the plurality of digital signal processing cores.

Abstract: A multi-core audio processor includes a data protocol interface configured to receive a stream of audio data, a plurality of data processing cores including a single sample processing core and a block data processing core, an audio fabric block configured to route samples of the stream between the data protocol interface and the plurality of data processing cores. The single sample processing core includes an execution unit configured to execute one or more low latency instructions for performing computations for the samples.

Abstract: A multi-core audio processor includes a plurality of data ports configured to receive and transmit data, wherein a first data port of the plurality of data ports is configured to receive data associated with a first stream, a first plurality of audio interface resources configured to perform operations on the data, and a multiplexing unit configured to route data between the plurality of data ports and the first plurality of audio interface resources, the multiplexing unit including a multiplexer associated with each of the first plurality of audio interface resources. The multi-core audio processor also includes a first plurality of transport buffers, at least one transport buffer associated with each of the first plurality of audio interface resources. A first set of buffers of the first plurality of transport buffers is configured to synchronously store data received from the first set of the first plurality of audio interface resources.