Abstract:
Vibration sensors are provided. The vibration sensor may include: a vibration assembly, the vibration assembly including a mass element and an elastic element, and the mass element being connected to the elastic element; a first acoustic cavity, the elastic element constituting one of sidewalls of the first acoustic cavity, and the vibration assembly vibrating to make a volume of the first acoustic cavity change in response to an external vibration signal; an acoustic transducer, the acoustic transducer being in communication with the first acoustic cavity and the acoustic transducer generating an electrical signal in response to a volume change of the first acoustic cavity; and a buffer, the buffer limiting a vibration amplitude of the vibration assembly, wherein the acoustic transducer has a first resonance frequency, the vibration assembly has a second resonance frequency, and the second resonance frequency of the vibration assembly is smaller than the first resonance frequency.
Abstract:
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 indicative of audio associated with an electrical system for at least one time interval. The method includes partitioning, by the one or more computing devices, the audio data for the time interval into a plurality of time windows. The method includes determining, by the one or more computing devices, a signal indicative of a presence of corona based at least in part on audio data collected within an identified time window of the plurality of time windows relative to audio data collected for a remainder of the time interval.
Abstract:
A method for monitoring the health of propellers in an aircraft is provided. The method includes receiving pressure waves generated by at least one rotating propeller and analysing data corresponding to the received pressure waves to detect tonal noise which is within a selected frequency range. If tonal noise at harmonics of the propeller rotational frequency within the selected frequency range is detected within the selected frequency range, it is established that the health of at least one propeller may be impaired and an alert is created for inspection and maintenance to take place.
Abstract:
Provided is a measuring method for measuring laser scanning velocity for a laser beam machining apparatus. The laser beam machining apparatus includes a mirror, and is configured to process a work by irradiating laser. The laser is irradiated by operating the mirror. The measuring method includes measuring processing sound of the work by the laser using the laser beam machining apparatus. Further, the measuring method includes calculating scanning velocity of the laser by analyzing a frequency of the measured processing sound using the laser beam machining apparatus.
Abstract:
A MEMS sensor has at least a movable element designed to oscillate at an oscillation frequency, and an integrated measuring system coupled to the movable element to provide a measure of the oscillation frequency. The measuring system has a light source to emit a light beam towards the movable element and a light detector to receive the light beam reflected back from the movable element, including a semiconductor photodiode array. In particular, the light detector is an integrated photomultiplier having an array of single photon avalanche diodes.
Abstract:
The frequency response of a microphone can be measured by feeding an acoustic spectrum generated from a pseudo-random bit sequence generator into the microphone and analysing the output using a Fourier analyser. The acoustic spectrum generator is portable and battery operated. A phase locked oscillator system is used to enable the output of a microphone under test to be analysed even after recording on magnetic tape. The device ensures that the sampling rate of the analogue to digital converter feeding the Fourier analyser is locked onto the drive frequency of the pseudo-random bit sequence generator.
Abstract:
A vibration detection apparatus is disclosed. The vibration detection apparatus comprises a body configured to have internal space, and a vibration sensor formed on the body and configured to sense vibration from a measuring object. Here, a space exists between the vibration sensor and a surface opposed to the vibration sensor of the body.
Abstract:
Provided is a method of estimating velocity of a vehicle, in which at least one black box is installed, the method including: receiving acoustic information from the black box, the acoustic information being synchronized with time of a certain image; transforming the acoustic information of a time domain to frequency data of a frequency domain via fast Fourier transformation (FFT); calculating revolutions per minute (RPM) of a main engine from the frequency data by using order analysis; and calculating velocity of the vehicle at the time of the certain image by using the RPM of the main engine and vehicle information.
Abstract:
An accident sound detection circuit includes an accident sound detection block that detects an accident sound from a sound signal inputted from an environmental sound detection unit and outputs an accident sound detection signal a power spectrum calculator for obtaining a power spectrum in regard to a sound signal when acquiring the accident sound detection signal outputted from the accident sound detection block as a trigger signal, a spectrum pattern calculator for forming a pattern of the power spectrum, and a pattern comparator circuit for comparing the formed spectrum pattern and a set pattern set in a pattern generating circuit beforehand and generating a final accident sound detection signal if the patterns coincide with each other.
Abstract:
Apparatus for automatically determining the total sound power emitted by a work machine. The noise testing system employs a processor and remote control to control the measurement of both exterior and interior sound generated by a work machine in either a dynamic or static operating mode.