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: 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 includes a base with a port extending therethrough, and a microelectromechanical system (MEMS) device coupled to the base. The MEMS device includes a diaphragm, a back plate, and a substrate. The substrate forms a back-hole. A capillary structure is disposed in the back-hole of the substrate, the cover, adjacent to the MEMS, or combinations thereof. The capillary structure includes a plurality of capillaries extending through the capillary structure. The capillary structure may have at least one hydrophobic surface and is configured to inhibit contaminants from outside the microphone from reaching the diaphragm via the port. In some embodiments, the capillary structure may protect against EMI.

Abstract: The disclosure relates to a microphone assembly including a multibit analog-to-digital converter configured to generate N-bit samples representative of a microphone signal. The microphone assembly also includes a first digital-to-digital converter configured to generate a corresponding M-bit digital signal based on N-bit digital samples, wherein N and M are positive integers and N>M. The microphone assembly may include a data interface configured to repeatedly receive samples of the M-bit digital signal and write bits of the M-bit digital signal to a data frame.

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: Systems and methods for active noise cancellation are provided. An example method includes receiving at least two reference signals associated with at least two reference positions. Each of the at least two reference signals includes at least one captured acoustic sound representing an unwanted noise. The reference signals are filtered by individual filters to obtain filtered signals. The filtered signals are combined to obtain a feedforward signal. The feedforward signal is played back to reduce the unwanted noise at a pre-determined space location. The individual filters are determined based on linear combinations of at least two transfer functions. Each of the at least two transfer functions is associated with one of the reference positions. In certain embodiments, the at least two reference signals are captured by at least two feedforward microphones.

Abstract: A microphone includes a first micro electro mechanical system (MEMS) motor, the first MEMS motor including a first diaphragm and a first back plate; and a second MEMS motor including a second diaphragm and a second back plate. The first diaphragm is electrically biased relative to the first back plate according to a first voltage, the second diaphragm is biased relative to the second back plate according to a second voltage, and a magnitude of the first voltage is different from a magnitude of the second voltage.

Abstract: A microphone assembly includes a capacitive MEMS transducer and a bias circuit having a DC output coupled to the transducer. The microphone assembly also includes a differential amplifier having a first input coupled to a first output of the transducer, the differential amplifier having a second input coupled to a second output of the transducer. The microphone assembly further includes a first impedance matching network and a second impedance matching network configured to balance a first capacitive load at the first input of the amplifier and a second capacitive load at the second input of the amplifier. Electrical signals applied by the transducer to the first and second inputs of the amplifier are matched or approximately matched in magnitude and 180 degrees or approximately 180 degrees out of phase with respect to each other.

Abstract: A surface-mountable MEMS microphone comprising a MEMS microphone die and an application-specific integrated circuit (ASIC) mounted inside a surface-mountable package housing, and fully enclosed therein. The surface-mountable package is a single, self-contained housing that provides an electrical interface to external circuitry for the enclosed MEMS microphone die and the ASIC, and provides electrical, physical, and environmental protection for the MEMS microphone die and the ASIC. The surface-mountable package allows external acoustic energy to enter the package interior via one or more acoustic ports and impinge on the diaphragm of the MEMS microphone die. The cover of the surface-mountable package comprises an acoustic port with ingress protection to limit dust and particle intrusion. The ingress protection can be a formed member that is part of the cover of the surface-mountable package having various shapes, an internal shield, or a combination of both a formed member and internal shield.

Abstract: A microphone device comprises a microphone die including a first microphone motor and a second microphone motor, an acoustic integrated circuit structured to process signals produced by the first microphone motor and the second microphone motor, and a sensor die stacked on top of the acoustic integrated circuit, wherein the sensor die comprises a pressure sensor. Another microphone comprises a microphone die including a first microphone motor and a second microphone motor and an integrated circuit die. The integrated circuit die comprises an acoustic integrated circuit structured to process signals produced by the first microphone motor and the second microphone motor, a pressure sensor, and a pressure integrated circuit structured to press signals produced by the pressure sensor.

Abstract: A microphone device includes a substrate having a cavity. The device also includes a microelectromechanical systems (MEMS) transducer mounted on the substrate outside of the cavity and an application specific integrated circuit mounted in the cavity. A first set of bonding wires connect the MEMS transducer to the ASIC and a second set of bonding wires connect the ASIC to a conductor within the cavity. An encapsulating material completely covers the ASIC and at least a portion of the second set of wires and is substantially confined within the cavity. A cover is installed over the substrate to cover the MEMS transducer, the encapsulating material, the ASIC, the first set of bonding wires, and the second set of bonding wires.

Abstract: Provided are systems and methods for utilizing digital microphones in low power keyword detection and noise suppression. An example method includes receiving a first acoustic signal representing at least one sound captured by a digital microphone. The first acoustic signal includes buffered data transmitted with a first clock frequency. The digital microphone may provide voice activity detection. The example method also includes receiving at least one second acoustic signal representing the at least one sound captured by a second microphone, the at least one second acoustic signal including real-time data. The first and second acoustic signals are provided to an audio processing system which may include noise suppression and keyword detection. The buffered portion may be sent with a higher, second clock frequency to eliminate a delay of the first acoustic signal from the second acoustic signal. Providing the signals may also include delaying the second acoustic signal.

Abstract: A first microphone is operated in a low power sensing mode, and a buffer at the first microphone is used to temporarily store at least some of the phrase. Subsequently the first microphone is deactivated, then the first microphone is re-activated to operate in normal operating mode where the buffer is no longer used to store the phrase. The first microphone forms first data that does not include the entire phrase. A second microphone is maintained in a deactivated mode until the trigger portion is detected in the first data, and when the trigger portion is detected, the second microphone is caused to operate in normal operating mode where no buffer is used. The second microphone forms second data that does not include the entire phrase. A first electronic representation of the phrase as received at the first microphone and a second electronic representation of the phrase as received at the second microphone are formed from selected portions of the first data and the second data.

Abstract: At a configurable filter bank, commands or command signals are received from an external processing device. The commands or command signals are effective to configure and connect selective ones of the plurality of elements in the filter bank. An acoustic signal is received from a transducer. The acoustic signal is converted to a PDM signal and the PDM signal is converted to a PCM signal.

Abstract: The present disclosure relates to microphone apparatus. One microphone apparatus includes an acoustic sensor, an electrical circuit including an acoustic activity detector, a frequency detection circuit and a control block, an internal clock signal generator coupled to the electrical circuit, and a host interface with external connections including a connection for an external clock signal and data. The microphone assembly has an acoustic activity detection mode of operation when the electrical circuit is clocked using the internal clock signal generator in the absence of an external clock signal at the host interface, and the electrical circuit is configured to provide an interrupt signal to the host interface upon detection of acoustic activity by the electrical circuit.

Abstract: A microphone apparatus including a MEMS transducer, an acoustic activity detector, a local oscillator, and an external-device interface standardized for compatibility with devices from different manufacturers is disclosed. The microphone apparatus has a first mode of operation during which the apparatus is clocked by the internal clock signal when the acoustic activity detector processes digital data for acoustic activity, and a second mode of operation during which the microphone apparatus is clocked by an external clock signal received at the external-device interface after voice activity is detected by the acoustic activity detector.

Abstract: A microphone includes a base; a first micro electro mechanical system (MEMS) device and a second MEMS device disposed on the base. The first MEMS device has a first diaphragm and a first back plate, and the second MEMS device has a second diaphragm and a second back plate. The first MEMS device and the second MEMS device are arranged such that positive pressure moves the first diaphragm towards the first back plate, and the positive pressure simultaneously moves the second diaphragm of the from second back plate.

Abstract: A surface mount package for a micro-electro-mechanical system (MEMS) microphone die is disclosed. The surface mount package features a substrate with metal pads for surface mounting the package to a device's printed circuit board and for making electrical connections between the microphone package and the device's circuit board. The surface mount microphone package has a cover, and the MEMS microphone die is substrate-mounted and acoustically coupled to an acoustic port provided in the surface mount package. The substrate and the cover are joined together to form the MEMS microphone, and the substrate and cover cooperate to form an acoustic chamber for the substrate-mounted MEMS microphone die.

Abstract: A method for reducing noise within an acoustic signal includes receiving at least a primary acoustic signal from a primary microphone and a secondary acoustic signal from a different, secondary microphone, wherein the primary acoustic signal includes a speech component emanating from a user and a noise component. The method also includes measuring a first value of a first coefficient based on the primary and secondary signals and performing a noise cancellation process based on the measured first value of the first coefficient to produce a set of noise-cancelled primary sub-bands. The method also includes generating, by the processor, a set of multiplicative gain mask values, the multiplicative gain mask values having a frequency dependency that is based at least in part on a pre-indicated approximate sound pressure level of the speech component.

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.