A micro-electro mechanical device includes a casing, a vibration sensor, a vibration membrane assembly, and a micro-electro mechanical microphone. The casing has a sound-receiving hole, and the vibration sensor is disposed in the casing. The vibration membrane assembly is disposed in the casing and corresponds to the vibration sensor. The micro-electro mechanical microphone is disposed in the casing and corresponds to the sound-receiving hole, and a back cavity of the micro-electro mechanical microphone is formed in the casing. The back cavity at least partially overlaps with areas corresponding to a vertical projection of the vibration membrane assembly.

A vibration rectification error correction circuit includes a first correction circuit that obtains a digital value based on a signal to be measured output from a sensor element configured to measure a physical quantity and corrects a vibration rectification error of the digital value by a correction function based on a product of values obtained by biasing the digital value.

An acoustic measuring device suitable for performing measurements on a surface in contact with a flow. This acoustic measuring device comprises an acoustic surface delimiting a cavity, which has an axis of revolution, which comprises a recess centered with respect to the axis of revolution, configured to house an acoustic sensor and which, in a longitudinal plane passing through the axis of revolution, follows a logarithmic profile which extends from a first edge separating the recess and the acoustic surface.

An acoustic measuring device suitable for performing measurements on a surface in contact with a flow. This acoustic measuring device comprises an acoustic surface delimiting a cavity, which has an axis of revolution, which comprises a recess centered with respect to the axis of revolution, configured to house an acoustic sensor and which, in a longitudinal plane passing through the axis of revolution, follows a logarithmic profile which extends from a first edge separating the recess and the acoustic surface.

The present invention relates to a drive for an electric application such as an electric motor, said drive including at least one microphone for registering noise signals occurring at the drive, wherein the microphone is connectable to a computing device for analysing the registered noise signals. The registered noise signals may be used for a maintenance process of the drive and/or a fine-tuning process of a drive control method of the drive. The present invention also relates to a maintenance process, in particular a predictive maintenance process for a corresponding drive. Furthermore, the present invention relates to a process for fine tuning a drive control method of a corresponding drive.

A sound measuring device includes: a light source that emits a laser beam; a frame including at least one reflective surface that faces a predetermined space through which sound travels, and transversely surrounds the predetermined space with respect to a sound propagation direction; and a light receiver that receives the laser beam multiply reflected by the at least one reflective surface. The at least one reflective surface is disposed to multiply reflect and cross the laser beam in the predetermined space as viewed from the sound propagation direction.

Systems, methods, and apparatus for corona detection using audio data are provided. In one example embodiment, the method includes obtaining, by one or more computing devices, audio data during at least one time interval, the time interval including a plurality of time windows; partitioning, by the one or more computing devices, the audio data into a plurality of window audio data each corresponding to a respective one of said time windows; and determining, by the one or more computing devices, a signal indicative of a presence of corona based at least in part on at least one window audio data relative to a remainder audio data.

A photoacoustic apparatus may include: a ring transducer configured to measure a photoacoustic signal generated from an object, and including a hollow space that is provided as a travel path of light and ultrasonic waves; a mirror part disposed along a light path of the light transmitted from the ring transducer, and configured to reflect the light transmitted from the ring transducer, and the ultrasonic waves generated from the object, and to adjust magnification of the mirror part according to a number of apertures of the photoacoustic apparatus; and a fluid tank including a transparent film that allows the photoacoustic signal to pass through the fluid tank, and accommodating a fluid, the ring transducer, and the mirror part inside the fluid tank.

A sensor package substrate disclosed in the present specification has a mounting area in which a sensor chip is mounted and a controller chip connected to the sensor chip. A through hole is formed in the sensor package substrate so as to overlap the mounting area in a plan view and to penetrate the substrate from one surface to the other surface thereof. The mounting area and the controller chip overlap each other in a plan view. According to the present invention, by reducing the thickness of an insulating layer, it is possible not only to reduce the distance of a wiring for the sensor chip and controller chip, but also to reduce the area of the substrate.

A sensor package substrate disclosed in the present specification has a mounting area in which a sensor chip is mounted and a controller chip connected to the sensor chip. A through hole is formed in the sensor package substrate so as to overlap the mounting area in a plan view and to penetrate the substrate from one surface to the other surface thereof. The mounting area and the controller chip overlap each other in a plan view. According to the present invention, by reducing the thickness of an insulating layer, it is possible not only to reduce the distance of a wiring for the sensor chip and controller chip, but also to reduce the area of the substrate.