Abstract: The present invention is a pressure coupling chamber (1) developed for comparison calibrations of acoustic pressure-sensitive hydrophone (2) in the frequency range from Hz to 1 kHz. A hydrophone (2), reference receiver unit (3) and acoustic source (6) under test are acoustically coupled in the chamber through the air-filled medium inside the pressure coupling chamber (1). Acoustic sources (6) that are going to create acoustic pressure in the pressure coupling chamber (1), placed on the side walls of the chamber (1) to surround the pressure-sensitive active surface of hydrophone (2), are driven to create a hydrostatic pressure effect in the related frequency range in the chamber. Calibration of tested hydrophone (2) with comparison method is carried out by measuring the output voltages of tested hydrophone (2) and the reference receiver unit (3).

Abstract: A fibre-optic hydrophone comprising a substantially incompressible tubular body, the tubular body generally having a geometry of a cylindrical shell defining an axis, and a deflectable outer wall, arranged to surround the tubular body in a distance thereof, and defining an axis that is arranged to substantially coincide with the axis of the tubular body. The hydrophone further comprising an optical fibre coil arranged on an outer surface of the outer wall, and a first and a second end lid arranged to seal the tubular body and the outer wall at a first end and a second end thereof, respectively, the first end lid and the second end lid being substantially incompressible. Additionally, the hydrophone comprising an outer cavity defined by an inner surface of the outer wall, an outer surface of the tubular body, the first lid, and the second lid; and an inner cavity defined by an inner surface of the tubular body, the first lid, and the second lid.

Abstract: A boat anchor monitoring system is disclosed and includes a status indicator and an anchor module that are operable to communicate with a base module. The anchor module includes a transmitter operable to transmit a signal containing a data payload on a set schedule. The base module on the boat is operable to determine if the signal strength exceeds, or is equal to a predetermined threshold value, in order to direct the status indicator to either display the anchor in a “Deployed” or “Not Deployed” position. The system may further include a time measurement component or water contact sensor that will direct the indicator to display the anchor in a deployed position if sufficient time has elapsed with no signal or the anchor module has contacted water. The system is also configured to prevent ignition if the anchor is determined to be deployed.

Abstract: A calling system for a personal watercraft includes processing circuitry. The processing circuitry is configured to: obtain a specific state signal indicating that the personal watercraft is in a given specific state; and wirelessly transmit a calling signal based on the specific state signal.

Abstract: A thermophone includes an inner core and an outer shell coaxial with the inner core. The inner core and outer shell enclose a volume filled with gas. A pair of posts extend radially from the inner core to the outer shell and extend longitudinally between the inner core and the outer shell. At least one longitudinal slot is formed along the outer shell and a fluid seal covers the slot. A thermoacoustic active element is disposed in the volume and heated by modulated current to generate alternating pressure on the outer shell and produce acoustic signals.

Abstract: The invention discloses a control system for LRA, applicable to an LRA having a speed sensing coil. The control system comprises a signal amplifier, an excitation device, a flow controller, a processing unit, and a driver. The processing unit is connected to the signal amplifier, the excitation device and the flow controller, so as to stop output, output the excitation signal as a driving signal or process the induction signal from the signal amplifier into an appropriate system damping coefficient and output as a driving signal when the flow controller outputs a stop, excitation or braking state signal, respectively.

Abstract: A space-division multiplexed optical fiber includes a relatively high refractive index optical core region surrounded by alternating regions of relatively low and relative high refractive index material, forming concentric high index rings around the core. The optical core region supports propagation of light along at least a first radial mode associated with the optical core region and a high index ring region supports propagation of light along at least a second radial mode associated with the high index ring region. The second radial mode is different from the first radial mode.

Abstract: A method of assembling a hydrophone is provided in which the method stacks ceramic rings, delrin washers, and LC-800 washers such that a top edge of a composite stack extends beyond a top of a hydrophone flange. By measuring the voltage on each ceramic ring while an end cap and a socket head cap screw are installed; the axial compression of each ceramic ring is quantified; thereby, providing an opportunity to equalize the axial compression of each ceramic ring to yield an accurately performing hydrophone.

Abstract: A movement and expression sensor has a plurality of fiber Bragg gratings (FBG) disposed along the length of an optical fiber, and the optical fiber is placed in contact with a subject's skin surface. The sensors are interrogated for reflected wavelength, which is converted into a temperature or a strain. A series of such measurements can be made to determine the movement or position of the sensor location. A garment may be formed using the sensors and an elastomeric material, such that the sensors may be worn and removed, and the movements of the elastomer in the areas of sensors measured as a wavelength shift to characterize movement or estimate location. The elastomeric garment may be formed as a mask, or a sock, such as for use with a face, or foot.

Abstract: A system, apparatus and method for determining an acoustic property of a fluid in a wellbore is disclosed. A faceplate is placed in the wellbore with a stepped surface of the faceplate in contact with the fluid. The stepped surface includes a non-stepped face and a stepped face. A first portion of an acoustic pulse passes from the faceplate into the fluid via the non-stepped face and a second portion of the acoustic pulse passes from the faceplate into the fluid via the stepped face. A first reflected acoustic pulse related to the first portion of the acoustic pulse is received. A second reflected acoustic pulse related to the second portion of the acoustic pulse is received. A measurement of the first reflected acoustic pulse and a measurement of the second reflected pulse are used to determine the acoustic property of the fluid in the wellbore.

Abstract: A sensor system includes a pressure sensor portion, and an accelerometer. Outputs from the sensor system are handled by a signal processing system that includes a first beamforming module for inputs from a pressure sensor, a second beamforming module for inputs from an accelerometer, and an adaptive beam interpolation module. A method for signal processing signals from both a pressure sensor and an accelerometer. An array of sensors transfers data wirelessly.

Abstract: At least embodiment is directed to an earpiece comprising a housing; and a field responsive fluid, where the field responsive fluid is in the housing, where the housing is part of the earpiece, and where the earpiece is configured to vary a field to vary an acoustical property of the field responsive fluid.

Abstract: A tow body and associated method have an acoustic projector that can be rotated about a vertical plane while the tow body is being towed through the water. In some embodiments, the tow body and method allow the tow body to be coupled to a tow cable while the tow cable is being towed through the water and under tension.

Abstract: A transducer for sub-ocean bottom imaging includes: a housing capable of withstanding hydrostatic pressure of about 9,000 pounds per square inch; a transmitting layer positioned within the housing to transmit two primary high frequency transmit beams that generate a low frequency signal whose frequency is an arithmetic difference between the two primary beams for high resolution sub-ocean bottom imaging while maintaining high spatial resolution or directivity; and a receiving layer collocated with the transmitting layer within the housing that is mechanically tuned to resonate at the difference frequency producing high receive sensitivity.

Abstract: An explosion-proof system for generating acoustic energy. An exemplary embodiment of the system includes a main housing defining an open housing space and an opening. A cover structure is configured for removable attachment to the main housing structure to cover the opening and provide an explosion-proof housing structure. The cover structure includes an integral head mass. An acoustic energy emitting assembly includes the head mass, and an excitation assembly disposed within the explosion-proof housing structure. An electronic circuit is disposed within the explosion-proof housing structure to generate a drive signal for driving the excitation assembly to cause the acoustic energy emitting assembly to resonate and generate acoustic energy. In one embodiment the acoustic energy is a beam of ultrasonic energy useful for testing ultrasonic gas detectors. A method is also described for testing ultrasonic gas leak detectors using an ultrasonic source.

Abstract: A sound sensor, a hydrophone including the sound sensor, and a pressure balancing device for using for the hydrophone are provided. The hydrophone includes: a sensor including a sensing part and a pressure balancing part; a printed circuit board (PCB) that is electrically connected to the sensor; a case that houses the sensor and the PCB and that has an opening at one side thereof; an elastic membrane that covers the opening of the case; and a signal line that is electrically connected to the PCB to be extended to the outside of the case. The pressure balancing part includes a diaphragm of a thin film and a support that supports the diaphragm. A pressure balancing hole is formed at one side of the pressure balancing part, and at the inside of the pressure balancing part, a channel that is connected to the pressure balancing hole is formed, and a compressible gas is filled in the channel.

Abstract: A sound source includes a bubble configured to be filled with a gas. The sound source also includes an actuator configured to perturb the gas within the bubble by changing the volume of the gas without adding gas to or removing gas from the bubble. The sound source also includes a processing circuit configured to provide a control signal to the actuator to cause the actuator to perturb the gas within the bubble at a frequency defined by the control signal.

Abstract: A vibrating element manufacturing method by which adhesion is stabilized and yield is improved, a vibrating element, a vibrating actuator, a lens barrel and a camera system. A vibrating element manufacturing method is provided with a first step of arranging an elastic body on a holding member, a second step of forming an electromechanical transducing element by injection molding on the surface of the elastic body, and a third step of sintering the electromechanical transducing element by heating and bonding the elastic body with the electromechanical transducer element.

Abstract: An active sonar system includes at least one transmitter to transmit an acoustic signal, at least one receiver to receive a reflected acoustic signal, and an electronic cabinet to control the at least one transmitter to transmit the acoustic signal and the receiver to receive the reflected acoustic signal. At least one transmitter includes at least one carbon nanotube transmitting transducer. At least one carbon nanotube transmitting transducer includes at least one first electrode, at least one second electrode, and an acoustic element. The acoustic element includes a carbon nanotube structure that is electrically connected to at least one first electrode and at least one second electrode.

Abstract: A sound source includes a tubular resonator configured to be filled with a gas. The exterior of the resonator includes rigid and elastomeric portions. The interior of the resonator includes a first volume and a second volume. The volumes are separated by a rigid tubular wall containing at least one orifice. The at least one orifice enables a flow of gas between the volumes. The resonator also includes at least one rigid tubular member configured to move along the rigid tubular wall. The position of the at least one rigid tubular member regulates at least one dimension of the path between the volumes. The sound source also includes a volume velocity actuator disposed within the resonator. The sound source also includes a processing circuit configured to provide a control signal to cause the volume velocity actuator to perturb the gas within the resonator at a defined frequency.

Abstract: Method, source and seismic vibro-acoustic source element configured to generate acoustic waves under water. The seismic vibro-acoustic source element includes an enclosure having first and second openings; first and second pistons configured to close the first and second openings; an actuator system provided inside the enclosure and configured to actuate the first and second pistons to generate a wave having first frequency; and a pressure mechanism attached to the enclosure and configured to control a pressure of a fluid inside the enclosure such that a pressure of the fluid is substantially equal to an ambient pressure of the enclosure.

Abstract: A technique includes demodulating a wavefield; generating spatial samples of the demodulated wavefield; and processing the samples to extract spectral components of the wavefield based at least in part on the demodulating.

Abstract: An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.

Abstract: A seismic energy source includes an inlet aperture and an inlet pipe in fluid communication with an outlet of the inlet aperture at an inlet end of the inlet pipe. The inlet pipe is in fluid communication with an accumulator at an outlet end of the inlet pipe. An outlet pipe is in fluid communication with the accumulator at an inlet end of the outlet pipe and is connected to an outlet valve at an outlet end of the outlet pipe. The outlet valve is actuated by fluid pressure in the outlet pipe. An actuation pressure of the valve, and diameter, length and material properties of the outlet pipe are selected to cause a reflected water pressure wave resulting from closure of the valve to travel within the outlet pipe at a selected velocity. Motion of the seismic source through the water provides water pressure to operate the source.

Abstract: An ultrasonic transducer for use in a fluid medium includes at least one housing having at least one inner space, at least one transducer core accommodated in the inner space, having at least one electroacoustic transducer element. The housing has at least one opening facing the fluid medium. The opening is covered at least partially by at least one sealing foil. An edge of the sealing foil is sealed by at least one sealing material.

Abstract: Components, such as a cutting element for an earth-boring drilling tool include an ultrasonic transducer coupled therewith, and configured to transmit an acoustic signal therethrough, and transmit a data signal to a data acquisition unit in response to receiving a returning echo of the acoustic signals. An earth-boring drilling tool, comprises a bit body including a plurality of components, an ultrasonic transducer, and a data acquisition unit operably coupled with the ultrasonic transducer. The data acquisition unit may be configured to receive the data signal and determine a temperature distribution of the component based, at least in part, on a time-of-flight of the acoustic signals and the returning echoes. Methods for forming such components and measuring a temperature of such components may relate to coupling and implementing such an ultrasonic transducer with a component of an earth-boring drilling tool.

Abstract: A sound source comprises a bubble configured to be filled with a gas, an actuator configured to perturb the gas within the bubble, and a processing circuit configured to provide a control signal to the actuator to cause the actuator to perturb the gas within the bubble at a frequency defined by the control signal.

Abstract: A relative positioning system enabling a user to return to a starting position or some other point on the user's path. The system may include an array of accelerometers. The output from the accelerometers may be integrated to quantify movement of the array. The various movements of the array may be reconstructed to determine a net two or three dimensional translation. The current location of the array may be compared to a reference point to derive at trajectory directing the user to the reference point, such as an originating point. The trajectory may be continuously or periodically updated. Applications may include various displays presenting images, numbers, pointers, paths, vectors, or data by digital screens, watch faces, or other devices integrated with or remote from the processor calculating the vector back to the point of origin.

Abstract: Sensor and communications systems are disclosed for communicating measurements from subsea equipment, such as at an offshore well, to the surface. A sensor for a physical parameter, such as pressure or temperature at a blowout preventer, capping stack, or conduit in communication with the same, is electrically connected to a subsea acoustic transponder. An acoustic communications device, for example an acoustic transducer and transceiver electronics deployed on a remotely-operated vehicle, interrogates the acoustic transponder with an acoustic signal, in response to which the acoustic transponder transmits an acoustic signal encoded with the measurement. The acquired measurement data are then communicated to a redundant network at the surface. The sensor and acoustic transponder systems can be installed after an event at the subsea equipment, such as blowout of the well.

Abstract: Sensor and communications systems for communicating measurements from subsea equipment, such as at an offshore well, to the surface. A sensor for a physical parameter, such as pressure or temperature at a blowout preventer, capping stack, or conduit in communication with the same, is electrically connected to a subsea acoustic transponder. An acoustic monitoring transponder deployed near the well periodically interrogates the acoustic transponder with an acoustic signal, in response to which the acoustic transponder transmits an acoustic signal encoded with the measurement. The measurement data are stored at the acoustic monitoring transponder. An acoustic communications device later interrogates the acoustic monitoring transponder to receive the stored measurement data for communication to a redundant network at the surface.

Abstract: A system and method for making an accurate estimate of the activation depth for an impulse acoustic source includes recording sounds produced by the activation of the underwater impulse acoustic source over a time period sufficient to capture reverberation, performing a cepstral scan of the recording to determine a quefrequency corresponding to the impulse from the underwater impulse acoustic source and deriving a depth estimate from the quefrequency corresponding to the impulse from the underwater impulse acoustic source.

Abstract: An acoustic mirror of alternately arranged layers of high and low acoustic impedances is manufactured in that a basic material having a first layer of the layer sequence is initially provided, on which a second layer of the layer sequence is created on the first layer such that the second layer of the layer sequence partially covers the first layer. Subsequently, a planarization layer is applied onto the layer sequence, and the planarization layer is removed in an area which in the common layer plane projects laterally beyond the second layer so as to result in a residual planarization layer. Finally, a termination layer is applied onto the layer sequence and the residual planarization layer.

Abstract: A remote power delivery system includes an electrically-conductive plate disposed adjacent to a sensor system of an underwater vehicle's hull. At least one toroidal coil is disposed between the plate and the face of the sensor system exposed to water. An AC voltage is applied to the plate so that a time-harmonic voltage is induced in each toroidal coil.

Abstract: A subsea monitoring system.

Abstract: An acoustic radiator for underwater application is provided by opposing boundaries mutually spaced and centered on a common axis, a plurality of radial barriers located perpendicular to and connected between the top and bottom boundaries to define a plurality of adjacent radial waveguides, and a plurality of transducers disposed in each radial waveguide, and with one group of transducers being located radially outwardly from another group, the groups being defined in part by all members of the group being the same distance from the apex of the radial waveguide.

Abstract: Systems and methods comprise marine geophysical equipment with polyurethane-based material at least partially covering a surface. The surface also at least partially coated with a suspension medium and with a biocide. A method comprises disposing such marine geophysical equipment in a body of water. A method comprises applying a suspension medium and a biocide to a surface at least partially covered with a polyurethane-based material.

Abstract: A sound source comprises a bubble configured to be filled with a gas, an actuator configured to perturb the gas within the bubble, and a processing circuit configured to provide a control signal to the actuator to cause the actuator to perturb the gas within the bubble at a frequency defined by the control signal.

Abstract: Taps on a beam-interrupt button of an underwater signaling transceiver are encoded as binary frequency shift-key modulated Golay codes, which are transmitted via 56-58 kHz compression waves generated by a ring-shaped electromechanical transducer. Light emitting diodes flash to signal the content of received signals and provide monitoring of the distance between divers. All components of the transceiver—except outer portions of input/output leads and a suction cup for attaching to the transceiver to a diver's mask—are completely encased in transparent plastic. The input/output leads allow an internal battery to be recharged, provide access to the internal processor for programming and data retrieval, and monitor whether the transceiver is submerged so that the transceiver can operate in an underwater mode or an above-water mode. Transceivers only communicate with other transceivers which use the same communication channel.

Abstract: Apparatus and methods are described for subsea pipeline servicing, including dewatering and chemical containment. A subsea pipeline service skid has a containment bladder affixed to the skid and in fluid communication with a skid mounted pump dimensioned to pump fluid from the subsea pipeline. A sensor system at the suction side of the pump detects the presence of seawater, water, chemical agent, or gas so the pump can be operated accordingly. The chemical agent used during dewatering operations of the pipeline is selectively pumped to the containment bladder subsea so the subsea vehicle can independently take the chemical agent to the surface.

Abstract: An underwater wireless sensor is provided. The underwater wireless sensor comprises a floating-diving device enabling the underwater wireless sensor to dive to a first predetermined water depth in response to a predetermined condition; a sensing device converting a plurality of environmental parameters into a plurality of environmental messages; a micro controller receiving the environmental messages and sending a command signal including the environmental messages; and a communication device receiving the command signal, sending the command signal via a wireless sensor network, receiving an external message including a second predetermined water depth, and sending the external message to the micro controller so that the micro controller performs a corresponding operation and sends out a control signal to enable the underwater wireless sensor to move to the second predetermined water depth.

Abstract: A ballistic-acoustic transducer system includes a processor and one or more acoustic sensors. The sensors are positioned in a body of water and are in communication with the processor. The system is configured such that acoustic energy generated by a non-explosive projectile as it impacts the water, enters the water, and sinks through the water, is sensed by the one or more acoustic sensors, and the processor is configured to process the acoustic energy sensed by the one or more acoustic sensors.

Abstract: A hydrophone for recording underwater sound includes a housing having an outer surface designed to serve as a boundary surface for an incident sound wave and at least one vibration sensor having a sensor surface for recording sound waves and for preparing a sensor signal. The sensor surface of the vibration sensor is in an opening of the housing. A hydrophone assembly includes a plurality of the hydrophones.

Abstract: A relative positioning system enabling a user to return to a starting position or some other point on the user's path. The system may include an array of accelerometers. The output from the accelerometers may be integrated to quantify movement of the array. The various movements of the array may be reconstructed to determine a net two or three dimensional translation. The current location of the array may be compared to a reference point to derive at trajectory directing the user to the reference point, such as an originating point. The trajectory may be continuously or periodically updated. Applications may include various displays presenting images, numbers, pointers, paths, vectors, or data by digital screens, watch faces, or other devices integrated with or remote from the processor calculating the vector back to the point of origin.

Abstract: A wireless communication system includes a transmitting device and a receiving device, in which the transmitting device generates a signal including information and transmits the signal by electromagnetic waves and ultrasonic waves in the same frequency in parallel, and in which the receiving device extracts the signal from at least one of the electromagnetic waves and the ultrasonic waves transmitted from the transmitting device and acquires the information included in the extracted signal.

Abstract: A system and method for making an accurate estimate of the activation depth for an impulse acoustic source includes recording sounds produced by the activation of the underwater impulse acoustic source over a time period sufficient to capture reverberation, performing a cepstral scan of the recording to determine a quefrequency corresponding to the impulse from the underwater impulse acoustic source and deriving a depth estimate from the quefrequency corresponding to the impulse from the underwater impulse acoustic source.

Abstract: An oscillator device having an oscillating member, a resilient support and a supporting member is produced. The oscillating member is supported by the resilient support for oscillation about an oscillation axis. The oscillating member is formed with a movable element having protrusions for adjusting its mass, the protrusions extending from the movable element parallel to the oscillation axis and being formed in pairs disposed at positions symmetrical with respect to the oscillation axis. A sectional area of each protrusion along a plane perpendicular to the oscillation axis is constant in the oscillation axis direction. A laser beam is projected to a cutting position of protrusions, so as to partly remove the protrusion. The protrusions are cut based on adjusting the cutting position. The sum of the lengths removed from the protrusions by the cutting becomes equal to a predetermined length to thereby adjust an inertia moment of the oscillating member.

Abstract: Provided is a faceplate for an In-The-Ear (ITE) hearing aid and a method of manufacturing a faceplate for an In-The-Ear (ITE) hearing aid in which the faceplate can be manufactured in a compact size, using a foldable flexible printed circuit board (PCB), while maintaining the quality, enabling mass-production, and reducing the manufacturing cost.

Abstract: The invention relates to a submarine antenna to be attached to the hull of a submarine, said antenna comprising a planar converter arrangement (15) which extends along the hull (11) when attached and which has a reflector (21) and a plurality of electroacoustic converter elements (20). Said converter elements are arranged next to and interspaced from each other and are arranged in front of the reflector (21) in the sound incidence direction. The aim of the invention is to optimize said lateral antenna for attachment to the submarine in terms of its weight and volume and signal-to-disturbance ratio.

Abstract: A ballistic-acoustic transducer system includes a processor and one or more acoustic sensors. The sensors are positioned in a body of water and are in communication with the processor. The system is configured such that acoustic energy generated by a non-explosive projectile as it impacts the water, enters the water, and sinks through the water, is sensed by the one or more acoustic sensors, and the processor is configured to process the acoustic energy sensed by the one or more acoustic sensors.

Abstract: An electroacoustic transducer, particularly for underwater use, having a ceramic body (10) and a pair of electrodes, whose flat electrodes (11, 12) are arranged on mutually averted end faces (101, 102) of the ceramic body (10). At least one electrode (11) is structured in order to effectively suppress the side-lobes in the directional characteristic for all spatial directions such that the density of the ceramic body (10) decreases from the body center to the body edge.