Abstract: A method for acoustic echo cancellation is disclosed herein. A microphone receives a second acoustic signal from a near-end environment, the second acoustic signal including a delayed version of the first acoustic signal from a far-end environment. A processor models a relationship between the first acoustic signal and the second acoustic signal using an adaptive filter. The adaptive filter uses sampling points of the first acoustic signal and the second acoustic signal along a timeline as inputs. The processor identifies a sampling point among the sampling points, wherein weight values of the adaptive filter associated with the identified sampling point experience a significant increase (e.g., 50% increase). The identified sampling point along the timeline represents an estimated delay between the first acoustic signal and the second acoustic signal. The processor further removes the delayed version of the first acoustic signal from the second acoustic signal based on the estimated delay.

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: A microphone includes a substrate defining an embedded cavity between a first surface of the substrate and an opposing second surface of the substrate, the first surface defining a first opening into the embedded cavity, a distance between the first surface and the second surface defining a substrate thickness. A cover is disposed over the first surface of the substrate and forms a housing, the cover including a port, the substrate thickness being greater than a height of the cover from the first surface of the substrate. A microelectromechanical systems (MEMS) transducer is disposed in the housing and mounted on the first surface of the substrate over the first opening, and an integrated circuit (IC) is disposed in the housing and electrically coupled to the MEMS transducer. The MEMS transducer and the IC are disposed in a front volume of the housing defined by the cover and the substrate.

Abstract: A microphone assembly is disclosed including a microelectromechanical system (MEMS) transducer and an electrical circuit disposed in a housing having an external-device interface. The electrical circuit is configured to determine whether a speech characteristic is present in an electrical signal produced by the transducer, attempt to authenticate the speech characteristic, and provide an interrupt signal to the external device interface only upon successful authentication of the speech characteristic.

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 microphone device includes a base and a microelectromechanical system (MEMS) transducer and an integrated circuit (IC) disposed on the base. The microphone device also includes a cover mounted on the base and covering the MEMS transducer and the IC. The MEMS transducer includes a diaphragm attached to a surface of the substrate and a back plate mounted on the substrate and in a spaced apart relationship with the diaphragm. The diaphragm is attached to the surface of the substrate along at least a portion of a periphery of the diaphragm. The diaphragm can include a silicon nitride insulating layer, and a conductive layer, that faces a conductive layer of the back plate. The MEMS transducer can include a peripheral support structure that is disposed between at least a portion of the diaphragm and the substrate. The diaphragm can include one or more pressure equalizing apertures.

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: A microphone circuit having an amplifier with an input operably coupled to a microphone motor also includes a low pass filter operably coupled to the output of the amplifier and a positive feedback network that operably couples to an output of the low-pass filter and to the amplifier input. For many useful application settings the aforementioned amplifier has unity gain while the positive feedback network has a fractional gain less than unity.

Abstract: A sensor device includes a substrate having a front surface and an opposing back surface. The back surface defines an indented region having an indented surface. The substrate defines a bottom port extending between the front surface and the indented surface. The sensor further includes a microelectromechanical systems (MEMS) transducer mounted on the front surface of the substrate over the bottom port. The sensor also includes a filtering material disposed on the indented surface and covering the bottom port. The filtering material provides resistance to ingression of solid particles or liquids into the sensor device. The filtering material is configured to provide high acoustic permittivity and have low impact on a signal-to-noise ratio of the sensor 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: A microphone device includes a housing including a substrate having a first surface and a cover disposed over the substrate, the housing including a sound port between the interior of the housing and the exterior of the housing. The device also includes a microelectromechanical systems (MEMS) transducer mounted on the substrate and an integrated circuit (IC) mounted on the substrate. The MEMS transducer of the device is electrically connected to the IC, and the IC of the device is electrically connected to a conductor on the substrate. An encapsulating material covers the IC. And an encapsulating material confinement structure is disposed between the MEMS transducer and the IC, wherein the encapsulating material confinement structure at least partially confines the encapsulating material around the IC.

Abstract: The present disclosure relates to an integrated circuit comprising a transconductance amplifier which is connectable to a microelectromechanical systems (MEMS) transducer. The transconductance amplifier comprises a first input coupled to a first current conveyor and a second input coupled to a second current conveyor for converting a single-ended or differential transducer signal voltage into an intermediate signal current representative of the transducer signal voltage through a shared reference resistor. The transconductance amplifier further comprises first and second output circuits coupled to the shared reference resistor and being configured to convert the intermediate current signal into a corresponding differential output current signal through first and second output terminals for driving a load.

Abstract: An integrated circuit includes a first amplifier and a second amplifier. A first impedance matching circuit is coupled to the first amplifier, a first charge pump, and a single MEMS transducer. A second impedance matching circuit is coupled to the second amplifier, a second charge pump, and to the single MEMS transducer. A first capacitive load as measured at an input of first amplifier, and a second capacitive load as measured at an input of the second amplifier exist. The first capacitive load and the second capacitive load are balanced with respect to each other. A single pressure change causes the single MEMS transducer to create a first electrical signal and a second electrical signal. Both the first electrical signal and the second electrical signal are matched or approximately matched in magnitude, and 180 degrees or approximately 180 degrees out of phase with respect to each other.

Abstract: A first acoustic transducer has an armature, and the armature moves within a magnetic field. The first transducer also comprises a first coil. A second acoustic transducer has a first outer circumferential edge and an inner circumferential edge. A housing includes at least portions of the first transducer and the second transducer. The first transducer is disposed at least partially within the cavity and within the inner circumferential edge of the second transducer. The first coil is fixed in space relative to the housing.

Abstract: A microphone assembly comprising: a housing including a base, a cover, and a sound port; a MEMS transducer element disposed in the housing, the transducer element configured to convert sound into a microphone signal voltage at a transducer output; and a processing circuit. The processing circuit comprising a transconductance amplifier comprising an input node connected to the transducer output for receipt of the microphone signal voltage, the transconductance amplifier being configured to generate an amplified current signal representative of the microphone signal voltage in accordance with a predetermined transconductance of the transconductance amplifier; and an analog-to-digital converter comprising an input node connected to receive the amplified current signal, said analog-to-digital converter being configured to sample and quantize the amplified current signal to generate a corresponding digital microphone signal.

Abstract: A microphone assembly includes a transducer and a processing circuit. The processing circuit includes an analog-to-digital converter (ADC) configured to receive, sample and quantize an electrical signal generated by the transducer to generate a corresponding digital signal. The processing circuit includes a feedback path including a digital loop filter configured to receive and filter the digital 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 configured to combine the electrical signal and the analog feedback signal.

Abstract: A first MEMS motor and s second MEMS motor share a common back volume and a common support structure, and the common support structure is configured to support a first diaphragm and the first back plate, and the common support structure is also configured to support the second diaphragm and the second back plate. A channel passes through the common support structure and communicates with the exterior environment, the channel being of a first diameter, the channel being disposed beyond an outer periphery of each back plate. An opening extends through the silicon nitride layer, the opening having a second diameter, the second diameter being less than the first diameter, the channel communicating with the opening. The opening has a length that is orthogonal to second diameter, and the first back plate and the second back plate have a thickness, wherein the length is no greater than twice the thickness.

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 microelectromechanical system (MEMS) device includes at least one substrate, a lid, a MEMS component, a sensor, and a power supply. The lid is coupled to the substrate so that the substrate and the lid cooperatively define an interior cavity. The MEMS component is disposed within the interior cavity. The sensor is disposed within the interior cavity and is arranged to detect a parameter of the interior cavity. The power supply provides current to the sensor. The power supply is configured to control current during a ramp-up transition of the current and a ramp-down transition of the current such that the ramp-up transition and the ramp-down transition have attenuated high-frequency components.

Abstract: Methods and systems for synchronizing audio streams. The method includes tagging a first presentation time to a frame buffer of a first audio stream and a second presentation time to a frame buffer of a second audio stream. The second audio stream is to be synchronized to the first audio stream. The method also includes aligning the second presentation time of the frame buffer of the second audio stream with the first presentation time of the frame buffer of the first audio stream, resampling the second audio stream so that each resampling point of the second stream is aligned with a corresponding sampling point in the first audio stream, and determining sample data for each resampling point of the second audio stream.