Abstract: A system that tracks physical activity over multiple venues to assess and track the performance of a user. Physical assessments from the different venues is tracked in a same profile of a user that is stored in, for example, a cloud-based system. The progress of the user is tracked, analyzed, and reported to facilitate a holistic tracking of progress towards personal and clinical goals.

Abstract: In at least one embodiment, an audio amplifier system is provided. The system includes a loudspeaker and an audio amplifier. The loudspeaker transmits an audio output into a listening environment. The audio amplifier is programmed to receive an audio input signal and to generate an excursion signal corresponding to a first excursion level of the voice coil based on the audio input signal. The audio amplifier is further programmed to limit the excursion signal to reach a maximum excursion level and to determine a target pressure for an enclosure of the loudspeaker based on the maximum excursion level. The audio amplifier is further programmed to generate a target current signal based at least on the target pressure and to convert the target current signal into a target voltage signal to a target driving signal to drive the voice coil to reach the maximum excursion level.

Abstract: In at least one embodiment, an audio amplifier system is provided. The system includes a loudspeaker and an audio amplifier. The loudspeaker transmits an audio output into a listening environment. The audio amplifier is programmed to receive an audio input signal and to generate an excursion signal corresponding to a first excursion level of the voice coil based on the audio input signal. The audio amplifier is further programmed to limit the excursion signal to reach a maximum excursion level and to determine a target pressure for an enclosure of the loudspeaker based on the maximum excursion level. The audio amplifier is further programmed to generate a target current signal based at least on the target pressure and to convert the target current signal into a target voltage signal to a target driving signal to drive the voice coil to reach the maximum excursion level.

Abstract: In at least one embodiment, an audio system for extracting online parameters is provided. The system includes a loudspeaker and at least controller. The loudspeaker transmits an audio signal in a listening environment. The at least one controller includes a signal processing block and an adaptive filter. The signal processing block is programmed to provide a driving signal u(n) to drive the loudspeaker to transmit the audio signal. The adaptive filter is programmed to receive the driving signal and to receive a first varying signal i(n) from the loudspeaker in response to the loudspeaker transmitting audio signal. The adaptive filter is further programmed to generate an admittance curve for the loudspeaker based at least on the driving signal and the first varying signal.

Abstract: In at least one embodiment, an audio amplifier system is provided. The system includes a loudspeaker and an audio amplifier. The loudspeaker transmits an audio output into a listening environment. The audio amplifier is programmed to receive an audio input signal and to generate an excursion signal corresponding to a first excursion level of the voice coil based on the audio input signal. The audio amplifier is further programmed to limit the excursion signal to reach a maximum excursion level and to determine a target pressure for an enclosure of the loudspeaker based on the maximum excursion level. The audio amplifier is further programmed to generate a target current signal based at least on the target pressure and to convert the target current signal into a target voltage signal to a target driving signal to drive the voice coil to reach the maximum excursion level.

Abstract: In at least one embodiment, an audio system for extracting online parameters is provided. The system includes a loudspeaker and at least controller. The loudspeaker transmits an audio signal in a listening environment. The at least one controller includes a signal processing block and an adaptive filter. The signal processing block is programmed to provide a driving signal u(n) to drive the loudspeaker to transmit the audio signal. The adaptive filter is programmed to receive the driving signal and to receive a first varying signal i(n) from the loudspeaker in response to the loudspeaker transmitting audio signal. The adaptive filter is further programmed to generate an admittance curve for the loudspeaker based at least on the driving signal and the first varying signal.

Abstract: In at least one embodiment, an audio amplifier system is provided. The system includes a loudspeaker and an audio amplifier. The loudspeaker transmits an audio output into a listening environment. The audio amplifier is programmed to receive an audio input signal and to generate an excursion signal corresponding to a first excursion level of the voice coil based on the audio input signal. The audio amplifier is further programmed to limit the excursion signal to reach a maximum excursion level and to determine a target pressure for an enclosure of the loudspeaker based on the maximum excursion level. The audio amplifier is further programmed to generate a target current signal based at least on the target pressure and to convert the target current signal into a target voltage signal to a target driving signal to drive the voice coil to reach the maximum excursion level.

Abstract: In at least another embodiment, an audio amplifier system including the memory and the audio amplifier is provided. The audio amplifier includes the memory and is programmed to receive an audio input signal and to generate a target current signal based on the audio input signal and a velocity of a diaphragm of a loudspeaker. The audio amplifier is further programmed to generate a corrected current signal based at least on the target current signal and on a predicted position of a voice coil of the loudspeaker and determine the predicted position of the voice coil of the loudspeaker based on a flux density value. The flux density value corresponds to a product of magnetic flux of an air gap for the voice coil in the loudspeaker and a length of a voice coil wire in the loudspeaker.

Abstract: In at least one embodiment, an audio amplifier system including a memory and an audio amplifier is provided. The audio amplifier includes the memory and is programmed to receive an audio input signal and to generate a target current signal based on the audio input signal. The audio amplifier is further configured to generate a first predicted position of a voice coil of a loudspeaker and to generate a first corrected current signal based on the target current signal and on the first predicted position of the voice coil. The audio amplifier is further configured to determine a pressure within a loudspeaker enclosure based at least on the first predicted position of the voice coil and determine a position of a passive radiator based at least on the pressure within the loudspeaker enclosure. The audio amplifier is further configured to generate a second predicted position of the voice coil.

Abstract: A quadrupole responder for an OQR-type gravity gradiometer comprises a housing, and a mass quadrupole positioned within the housing. The mass quadrupole has a pair of sides, and also has a center of mass between the sides. At least a pair of torsion spring flexures are provided by pins connecting said side of said mass quadrupole to the housing. The torsion spring flexures provide an axis of rotation which passes through the center of mass of the mass quadrupole and through both spring flexures. The pins are integral with the mass quadrupole.

Abstract: A wearable sensor system with gesture recognition for measuring physical performance 98 includes a sensor ring 100 for providing signals corresponding to finger movement to an information processor 101. The sensor ring 100 internally includes an accelerometer 106 for measuring motion of a predetermined finger, the measured motion corresponding to an exercise routine performed by a user of the system 98, a processor 109 for conditioning the signals from the accelerometer 106, and a transceiver 108 for transmitting the conditioned signals to the information processor 101 for display and feedback to the user for accessing the quality of the exercise. The system 98 further includes means for allowing the user to start and stop the processing of the measured finger motion by moving the finger with sensor ring 100 thereon a predetermined distance and speed.

Abstract: Systems and methods for determining a bias-corrected value of at least one component of a gravity gradient tensor using a gravity gradiometer and a measurement bias of the gravity gradiometer wherein the measurement bias varies with time, by taking at least three measurements with the gravity gradiometer positioned in at least two orientations. Any gravity gradiometer can be used, including a Cross-Component Gravity Gradiometer (CCGG), an Orthogonal Quadrupole Responder (OQR), an In-Line Responder (ILR), a Diagonal-Component Gravity Gradiometer, or a Multi-Component Gravity Gradiometer (MCGG).

Abstract: An assessment of a subject's fitness is evaluated by having the subject go through whole body weight-bearing movement, with cuing provided to direct the subject's movements, and feedback provided to keep the subject at a desired exercise intensity. The subject's reaction to the exercise may be measured, for example with the subject's movements being tracked. An evaluation may be made, based at least in part on the measured reaction, for example by using data from the movement tracking, possibly in conjunction with data obtained by earlier testing, for example using a similar test protocol.

Abstract: Several push-pull linear hybrid class H amplifiers are disclosed. A split power rail provides a positive supply rail and a negative supply rail in response to a power supply control voltage. A push-pull amplifier stage is powered by the positive and negative supply rails. The amplifier stage receives an input signal and provides a corresponding amplified output signal. A power supply control circuit provides the power supply control voltage in response to the smaller of the positive and negative supply rails, and the input signal.

Abstract: A quadrupole responder for an OQR-type gravity gradiometer comprises a housing, and a mass quadrupole positioned within the housing. The mass quadrupole has a pair of sides, and also has a center of mass between the sides. At least a pair of torsion spring flexures are provided by pins connecting said sideof said mass quadrupole to the housing. The torsion spring flexures provide an axis of rotation which passes through the center of mass of the mass quadrupole and through both spring flexures. The pins are integral with the mass quadrupole.

Abstract: Systems and methods for determining a bias-corrected value of at least one component of a gravity gradient tensor using a gravity gradiometer and a measurement bias of the gravity gradiometer wherein the measurement bias varies with time, by taking at least three measurements with the gravity gradiometer positioned in at least two orientations. Any gravity gradiometer can be used, including a Cross-Component Gravity Gradiometer (CCGG), an Orthogonal Quadrupole Responder (OQR), an In-Line Responder (ILR), a Diagonal-Component Gravity Gradiometer, or a Multi-Component Gravity Gradiometer (MCGG).

Abstract: A quadrupole responder for an OQR-type gravity gradiometer comprises a housing, and a mass quadrupole positioned within the housing. The mass quadrupole has a pair of sides, and also has a center of mass between the sides. At least a pair of torsion spring flexures are provided by pins connecting said side of said mass quadrupole to the housing. The torsion spring flexures provide an axis of rotation which passes through the center of mass of the mass quadrupole and through both spring flexures. The pins are integral with the mass quadrupole.

Abstract: Several push-pull linear hybrid class H amplifiers are disclosed. A split power rail provides a positive supply rail and a negative supply rail in response to a power supply control voltage. A push-pull amplifier stage is powered by the positive and negative supply rails. The amplifier stage receives an input signal and provides a corresponding amplified output signal. A power supply control circuit provides the power supply control voltage in response to the smaller of the positive and negative supply rails, and the input signal.

Abstract: A wearable sensor system with gesture recognition for measuring physical performance 98 includes a sensor ring 100 for providing signals corresponding to finger movement to an information processor 101. The sensor ring 100 internally includes an accelerometer 106 for measuring motion of a predetermined finger, the measured motion corresponding to an exercise routine performed by a user of the system 98, a processor 109 for conditioning the signals from the accelerometer 106, and a transceiver 108 for transmitting the conditioned signals to the information processor 101 for display and feedback to the user for accessing the quality of the exercise. The system 98 further includes means for allowing the user to start and stop the processing of the measured finger motion by moving the finger with sensor ring 100 thereon a predetermined distance and speed.

Abstract: The invention provides a method of locating, in terrain containing oil sand deposits and also containing shale, clean oil sands deposits (i.e. those not containing significant shale) which are large enough for economic exploitation. The method includes flying a high sensitivity gravity gradiometer over the terrain and measuring at least one component, preferably the vertical component, of the local gravity gradient field at a number of points in a grid pattern on the terrain. The densities of sand and shale are normally approximately the same, making it difficult to distinguish them. However in an oil sands environment, there can be a sufficient difference in bulk density such that by using a very sensitive gravity gradiometer, or by otherwise reducing the noise signal using appropriate surveying methods, large clean oil sand deposits can be distinguished from other oil sand deposits not large enough for economic exploitation.