Voice command recognition and natural language recognition are carried out using an accelerometer that senses signals from the vibrations of one or more bones of a user and receives no audio input. Since word recognition is made possible using solely the signal from the accelerometer from a person's bone conduction as they speak, an acoustic microphone is not needed and thus not used to collect data for word recognition. According to one embodiment, a housing contains an accelerometer and a processor, both within the same housing. The accelerometer is preferably a MEMS accelerometer which is capable of sensing the vibrations that are present in the bone of a user as the user is speaking words. A machine learning algorithm is applied to the collected data to correctly recognize words spoken by a person with significant difficulties in creating audible language.

A digital microphone includes at least one integrator; a state detection and parameter control component directly coupled to an output of the integrator; and a signal processing component coupled to an output of the state detection and parameter control component, wherein a parameter of the signal processing component includes a first value in a first operational mode and a second value in a second operational mode different from the first operational mode.

In accordance with an embodiment, a system includes a digital calibration filter device configured to receive a digital input signal based on a sensor output signal from a sensor, receive a sensor-specific control signal, and perform digital filter processing of the digital input signal to produce a calibrated output signal, wherein the digital filter processing is based on the sensor-specific control signal; and a control device configured to select the sensor-specific control signal from a plurality of sensor-specific control signals based on an ascertained influencing parameter, and provide the sensor-specific control signal to the digital calibration filter device.

A MEMS transducer for interacting with a volume flow of a fluid includes a substrate which includes a layer stack having a plurality of layers which form a plurality of substrate planes, and which includes a cavity within the layer stack. The MEMS transducer includes an electromechanical transducer connected to the substrate within the cavity and including an element which is deformable within at least one plane of movement of the plurality of substrate planes, deformation of the deformable element within the plane of movement and the volume flow of the fluid being causally correlated. The MEMS transducer includes an electronic circuit arranged within a layer of the layer stack, the electronic circuit being connected to the electromechanical transducer and being configured to provide a conversion between a deformation of the deformable element and an electric signal.

In one embodiment of an audio system, a transducer can be coupled to a passive acoustic directional amplifier to provide various benefits and improvements, including improvements to: speech intelligibility, signal-to-noise ratio, effective equivalent input noise, at-a-distance acoustic signal reception, and directional preference. In another embodiment, the shape of an interior surface of a passive acoustic directional amplifier is provided. In another embodiment, the material properties of an interior surface of a passive acoustic directional amplifier are provided.

A piezoelectric microelectromechanical systems (MEMS) microphone is provided comprising a substrate including walls defining a cavity and at least one of the walls defining an anchor region, a piezoelectric film layer supported by the substrate at the anchor region; an electrode disposed over the piezoelectric film layer and adjacent the anchor region and including an edge adjacent the anchor region having two straight portions and a protruding portion between the two straight portions, and the wall of the cavity that defines the anchor region including an indent corresponding in shape to the protruding portion of the electrode. A method of manufacturing such a MEMS microphone is also provided.

A piezoelectric microelectromechanical system microphone comprises a support substrate, a piezoelectric element configured to deform and generate an electrical potential responsive to impingement of sound waves on the piezoelectric element, the piezoelectric element attached to the support substrate about a perimeter of the piezoelectric element, a sensing electrode disposed on the piezoelectric element and configured to sense the electrical potential, and corrugations defined in the piezoelectric element about the perimeter of the piezoelectric element to release residual stress and improve sensitivity of the piezoelectric microelectromechanical system microphone.

A MEMS speaker can include an electrostatically driven, corrugated MEMS structure to move air without a magnet, coil, or traditional speaker membrane, and thus provide a low-power, compact speaker with a large acoustically active area in a small volume. Neighboring folds in the corrugated MEMS structure may form pairs of MEMS electrodes that can be pushed together and/or pulled apart to deform the MEMS structure in a breathing motion that generates pressure differentials on opposing sides of the corrugated MEMS structure to generate sound.

An impedance circuit for a charge pump arrangement and a charge pump arrangement are disclosed. In an embodiment, the impedance circuit includes a first current mirror circuit with a first bias serving as a current input terminal, a first output serving as a current output terminal and a first input for coupling with a pre-selected potential. The impedance circuit further includes a first charge pump for biasing the first current mirror circuit with a first reference current, wherein the first charge pump includes a first biasing output coupled with the first bias of the first current mirror circuit.

A microphone unit has a transducer, for generating an electrical audio signal from a received acoustic signal; a speech coder, for obtaining compressed speech data from the audio signal; and a digital output, for supplying digital signals representing said compressed speech data. The speech coder may be a lossy speech coder, and may contain a bank of filters with centre frequencies that are non-uniformly spaced, for example mel frequencies.