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: In one aspect, a low frequency driver is provided having a diaphragm operable to produce sound, a front volume, and an outlet that receives sound from the front volume and directs sound out from the low frequency driver. The low frequency driver further includes a low-pass filter chamber in communication with the front volume.

Abstract: An acoustic receiver employs one or more housing endplates recessed below an edge of a sidewall of the housing. In some implementations, a cured b-stage material is disposed in a recess along an interface between an endplate and a sidewall of the housing, wherein the cured b-stage material acoustically seals at least a portion of the housing. In some implementations, both a top housing endplate and a bottom housing endplate are recessed and have cured b-stage material disposed in respective recesses along an interface between the endplates and housing sidewalls wherein the cured b-stage material acoustically seals a top and bottom portion of the housing.

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 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: An acoustic apparatus and method produces an acoustic signal in response to an electrical input signal applied to an acoustic receiver. The acoustic signal is converted to an electrical output signal that is proportional to a sound pressure of the acoustic signal, using an electro-acoustic transducer. In some embodiments the apparatus and method determine whether there is a change in the acoustic signal indicative of a change in an acoustic load coupled to the receiver by comparing the electrical output signal to reference information. The change in acoustic load, in one example, is attributable to ear wax accumulation in an output of the acoustic receiver or acoustic passage in the ear canal of a user or is attributable to seal leakage.

Abstract: The disclosure describes devices and methods of providing a DC bias voltage in a microphone assembly. Particularly, one implementation of such a device may be implemented on an integrated circuit that includes a direct current (DC) bias circuit. The DC bias circuit may be coupled to a transducer and configured to supply a DC bias signal to the transducer. The DC bias circuit includes a multi-stage charge pump and a low pass filter (LUFF) circuit. The multi-stage charge pump includes transistors that are fabricated with deep trench isolation (DTI).

Abstract: An acoustic transducer for generating electrical signals in response to acoustic signals, comprises a first diaphragm having a first corrugation formed therein. A second diaphragm has a second corrugation formed therein, and is spaced apart from the first diaphragm such that a cavity having a pressure lower than atmospheric pressure is formed therebetween. A back plate is disposed between the first diaphragm and the second diaphragm. One or more posts extend from at least one of the first diaphragm or the second diaphragm towards the other through the back plate. The one or more posts prevent each of the first diaphragm and the second diaphragm from contacting the back plate due to movement of the first diaphragm and/or the second diaphragm towards the back plate. Each of the first corrugation and the second corrugation protrude outwardly from the first diaphragm and the second diaphragm, respectively, away from the back plate.

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.

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 pre-distorted electrical excitation signal is generated for an acoustic transducer having an armature and a non-linear transfer characteristic by applying an electrical input signal (x) representative of a desired acoustic output to a computable non-linear function that is a function of the electrical input signal (x). When applied to an input of the transducer, the pre-distorted electrical excitation signal results in an improved acoustic output signal.

Abstract: The disclosure describes devices and methods for starting up a microphone assembly. The device may be implemented on an integrated circuit that includes a direct current (DC) bias circuit. The DC bias circuit may be coupled to a transducer and configured to supply a DC bias signal to the transducer. The DC bias circuit includes a multi-stage charge pump and a low pass filter (LPF) circuit. The LPF circuit includes an adjustable resistance and a capacitor. A resistance of the adjustable resistance may be reduced to reduce the settling time of the LPF while starting (e.g., turning on) the microphone assembly.

Abstract: A system and method in an audio signal electrical circuit including a feedback loop with a digital filter coupled to a current digital to analog converter (IDAC) includes providing an output signal from the IDAC to analog elements of the audio signal electrical circuit, the output signal from the IDAC based upon a reference signal input to the IDAC when an output of the digital filter is not input to the IDAC. The system and method also include comparing an output signal of the audio signal electrical circuit to a reference, and calibrating the audio signal electrical circuit to correspond the output signal of the audio signal electrical circuit to the reference. Calibration of the audio signal electrical circuit enables more precise control of a cut-off frequency of a microphone signal when the output of the digital filter is input to the IDAC.

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 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 in a transducer assembly having an external-device interface coupled to a communication protocol interface of the transducer assembly. The transducer assembly is configured to convert an input signal having one physical form to an output signal having a different physical form. At least two electrical signals are received on corresponding contacts of the external-device interface of the transducer assembly. A characteristic of at least one of the electrical signals is determined by evaluating a logic transition of the signal. A unique identity assigned to the transducer assembly is determined based on the characteristic.

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: An electroacoustic transducer includes an armature that is mounted for deflection between magnets where an elongated portion of the armature includes a protrusion on opposite sides thereof for limiting the deflection of the armature. The protrusions are arranged transversely with respect to the elongated portion of the armature. Among other advantages, deflection of the armature is limited to provide improved shock performance. In one example, the protrusions are located within a magnet zone of the electroacoustic transducer.

Abstract: A system and method provides for multibeam keyword detection. A composite audio signal may include sound components. The system and method groups the sound components into subsets based on the angles of arrival of sound components. Keyword detectors evaluate each subset and determine whether a keyword is present.

Abstract: An acoustic transducer for generating electrical signals in response to acoustic signals, comprises a first diaphragm having a first corrugation formed therein. A second diaphragm has a second corrugation formed therein, and is spaced apart from the first diaphragm such that a cavity having a pressure lower than atmospheric pressure is formed therebetween. A back plate is disposed between the first diaphragm and the second diaphragm. One or more posts extend from at least one of the first diaphragm or the second diaphragm towards the other through the back plate. The one or more posts prevent each of the first diaphragm and the second diaphragm from contacting the back plate due to movement of the first diaphragm and/or the second diaphragm towards the back plate. Each of the first corrugation and the second corrugation protrude outwardly from the first diaphragm and the second diaphragm, respectively, away from the back plate.