Abstract: The present invention relates to a method and an acoustic measurement system for determining individual noise sound contributions of a plurality of physical noise sources of a motorized vehicle at a target or reference location. The method comprises steps of placing a plurality of reference microphones at respective reference positions adjacent to respective ones of the physical noise sources, placing a measurement microphone at the target location, recording a plurality of noise sound signals and recording a target noise signal. The plurality of noise sound signals are adaptively separated using blind source separation to produce a plurality of mutually independent noise sound signals representing respective estimated noise sound signals of the plurality of physical noise sources.

Abstract: A method of determining a property of a sound field from a plurality of measured sound field parameters, the method comprising: receiving a plurality of measured sound field parameters each indicative of a sound field parameter measured by a sensor of an array of sensors, the sensor being positioned at a measurement position; providing a model of a sound field, the model comprising a set of elementary waves and having associated with it a set of model parameters; computing, from the model, computed values of the sound field parameter at each of the measurement positions and as a function of said model parameters; determining a set of parameter values of the model parameters so as to reduce an error measure by performing an iterative minimization process including a plurality of iterations, the error measure comprising an error term operable to compare the computed and the measured sound field parameters; computing the property of the sound field from the determined set of model parameters.

Abstract: The present invention relates to a microphone test stand comprising a slide assembly with a microphone holder surrounded by a first acoustic sealing member. The slide assembly is movable in a first direction between a first position outside an acoustical chamber with an exposed state of the microphone holder and a second position inside the acoustical chamber in a shielded state of the microphone holder. An electrical connector comprises a set of electrical connector terminals which is connectable to a set of microphone terminals for receipt of a microphone response signal from a microphone assembly arranged in the microphone holder in response to a test sound pressure in the acoustical chamber.

Abstract: A method of determining a focused output signal of a sensor array comprising a plurality of sensors, each sensor being operable to output a sensor output signal responsive to a measured quantity, the focused output signal being indicative of a calculated quantity at a focus point; the method comprising: receiving a respective measured sensor output signal from each of the sensors; computing the focused output signal by performing a focusing calculation with respect to the measured sensor signals; wherein the method further comprises determining a subset of mesh points of a set of predetermined mesh points, each mesh point having at least one pre-computed filter parameter associated with it; and wherein computing the focused output signal comprises performing an interpolation with respect to the subset of mesh points so as to obtain an interpolated focused output signal.

Abstract: For determining a subjective property such as loudness of a binaural sound signal left and right sound pressures in the left and right ears of a human being, resulting from the binaural sound signal, are determined. The left and right sound pressures are frequency analyzed to obtain left and right frequency spectra. In each frequency band, the diotic (common) sound pressure in the left and right ears is determined, which would result from a plane wave frontal incidence on the human being, and that would produce the same perceived loudness as the frequency bandwidth limited left and right sound pressures. In each frequency band the inverse frontal head related transfer functions are used to determine the free-field sound pressure that would produce the same perceived loudness as the diotic sound pressure. The loudness is determined as the loudness of the totality of frequency bandwidth limited free field sound pressures, preferably using the international standard ISO 532.

Abstract: A fiber optical accelerometer comprising a base structure, a first seismic mass movably coupled to the base structure through a first hinge element, a second seismic mass movably coupled to the base structure through a second hinge element, an optical fiber coupled to the first and second seismic masses at first and second attachment joints, respectively, to subject the optical fiber to varying strain by displacement of the first and second seismic masses about the first and second hinge structures, respectively.

Abstract: A method of determining a focused output signal of a sensor array comprising a plurality of sensors, each sensor being operable to output a sensor output signal responsive to a measured quantity, the focused output signal being indicative of a calculated quantity at a focus point; the method comprising: receiving a respective measured sensor output signal from each of the sensors; computing the focused output signal by performing a focusing calculation with respect to the measured sensor signals; wherein the method further comprises determining a subset of mesh points of a set of predetermined mesh points, each mesh point having at least one pre-computed filter parameter associated with it; and wherein computing the focused output signal comprises performing an interpolation with respect to the subset of mesh points so as to obtain an interpolated focused output signal.

Abstract: The present invention relates to units or modules for data acquisition that may either be used as stand alone units or be used to form a modular system where a plurality of modules are mounted together in a frame or rack structure as well as combinations of such stand-alone units and frames.

Abstract: Disclosed herein is a method of reconstructing a sound field. The method comprises receiving measured values indicative of a first acoustic quantity measured at a set of measurement locations; defining a set of virtual source locations; and computing a second acoustic quantity for at least one target location from one or more wave functions each representative of a respective sound field originating from a respective one of the defined set of virtual source locations; wherein the one or more wave functions are weighted by respective one or more weighting factors, and wherein computing comprises determining the one or more weighting factors from a least-norm fit of the one or more wave functions to the received measured values.

Abstract: The present invention provides a method and an apparatus for in situ test of transducers comprising sensing elements and associated conditioning preamplifiers. The invention makes it possible to evaluate the characteristics of the complete transducer by means of higher integration of the transducer circuitry. Tests can be performed from a remote central location without additional wiring and while the transducer is in operating environment. Testing is performed by superposing test signals and test sequence control signals on the wiring for the transducer output signal, hereby offering flexibility without sacrificing simplicity. Test signalling is by additional circuitry in the transducer interpreted and routed to the input of the conditioning preamplifier based on signalling from the remote test generator, and the signals engendered from the test signals can be analyzed from a remote analyzing system for complete qualifications of the transducer under test.

Abstract: A micromachined component such as a transducer having a support structure with a rigid plate secured to the surface of the support structure by means of support arms directly interconnecting the rigid plate and the support structure at discrete locations. A diaphragm of a substantially non-conductive material is secured to the support structure along its periphery at a predetermined distance from the rigid plate. The rigid plate has a surface facing the air gap carrying an electrically conductive surface portion on that surface, and the diaphragm has a surface facing the air gap carrying an electrically conductive surface portion on that surface. For each support arm, at least one of the electrically conductive surface portions is separated from the support arm at a distance along the surface carrying the respective electrically conductive surface portion. This construction ensures a high leakage resistance and a low parasitic capacitance.