204 results about "Acoustic propagation" patented technology

Transducers and transducer modules having the transducers are disclosed. An embodiment discloses a transducer that includes a conductive layer having a U-shaped slit toward its swing end. The slit is configured to enhance a haptic feedback or an acoustic propagation, or adjust a resonant mode.

Methods, apparatus, and systems for accurately estimating acoustic propagation velocity are described. One method comprises deploying in a marine environment a towed seismic spread comprising a plurality of acoustic positioning transmitters and a plurality of positioning point receivers, and using travel times for signals between at least some of the transmitters and point receivers to derive a mathematical model describing acoustic propagation velocity for the marine environment as a function of at least one spread spatial dimension, distances between transmitters and receivers, and any combination thereof. This abstract is provided to comply with the rules requiring an abstract, and allows a reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

The invention provides a method for carrying out ultrasonic inspection on residual stress of an aluminium alloy pre-stretching board by water immersion, belonging to the field of non-destructive inspection. The method comprises the following steps of preparing a reference block; carrying out measurement and calibration; measuring the residual stress. In the method, the water immersion method is adopted, and the temperatures in stress calibration and stress measurement processes can be ensured to be consistent by controlling the water temperature not to be changed, thus eliminating the effects of temperature difference on the ultrasonic wave speed and eliminating temperature errors; besides, an automatic scanning frame is adopted instead of manual scanning, so that the distance between a probe and the surface of a material to be measured in the measurement process can be ensured not to be changed, thus eliminating the effects of coupling condition difference on sound propagation time and eliminating the coupling errors. The method is beneficial to non-destructive evaluation of the near surface residual stress of the aluminium alloy pre-stretching board.

A method, device and system enhance an audio signal in a receiving device. The method comprises acoustically propagating a target signal from an acoustic source along an acoustic propagation path, providing a propagated acoustic signal at the receiving device; converting the received propagated acoustic signal to a propagated electric signal, the received propagated acoustic signal comprising the target signal, noise and possible other sounds from the environment as modified by the propagation path from the acoustic source to the receiving device; wirelessly transmitting a signal comprising the target audio signal to the receiving device; receiving the wirelessly transmitted signal in the receiving device; retrieving a streamed target audio signal from the wirelessly received signal comprising the target audio signal; and estimating the target signal from the propagated electric signal and the streamed target audio signal using an adaptive system.

A temperature measurement system is characterized by at least one passive surface acoustic wave (SAW) temperature sensor. The sensor includes at least one piezoelectric substrate having an interdigital SAW transducer disposed upon the piezoelectric substrate for conversion of an RF signal into an acoustic wave and vice versa. At least three additional SAW elements are also disposed on the substrates in a manner such that they define two acoustic propagation paths that are non-parallel relative to the crystal axes of the substrates, and such that the temperature coefficients of delay in the two tracks differ. The SAW elements receive a signal from the SAW transducer and produce response signals. The response signals combine to produce a signal with a power spectral density such that the integrated power within each of two specified portions of the spectrum provides an indicator of the temperature. This change in the power spectral density of the sensor response signal is measured by an interrogator, and yields a measure of the temperature of the sensor.

An acoustic-propagation-time measuring apparatus includes an acoustic transmitting and receiving section having an acoustic element capable of transmitting and receiving acoustic waves, an A/D converter which converts an echo signal reflected from a target object to be measured into a digital signal, an inverse-analysis section that converts the digital echo signal into an impulse signal through inverse analysis where the digital echo signal is multiplied by an inverse matrix, a calculating section that measures an acoustic propagation time and a time difference based on the digital echo signal converted to the impulse signal, and a display section which displays the acoustic propagation time and time difference calculated by the calculating section.

A test system for evaluates acoustic feedback characteristics of a listening device by changing the transfer function of the signal path from an acoustic output to an acoustic input of the listening device. A variable filter comprises an acoustic input, an acoustic output, and a control unit for changing a transfer function of the filter. First and/or second acoustic propagation elements propagate acoustic sound, the first acoustic propagation element acoustically connecting the acoustic output of the listening device with the acoustic input of the variable filter, the second acoustic propagation element acoustically connecting the acoustic output of the variable filter with the acoustic input of the listening device; wherein the system is configured to allow a determination of acoustic feedback or a level of acoustic feedback of the listening device at different frequencies.

The invention discloses a centrifugal pump flow induction noise numerical prediction method which is used for computing the sound source feature of flow noise on the basis of the test results of a centrifugal pump performance test. The method can well overcome the shortcomings that in a traditional computing method, the influence from a pump body structure on acoustic propagation is not considered, and eddy broadband noise is ignored. Centrifugal pump inner flow analysis and far-field noise value computing results are used in centrifugal pump low-noise waterpower design, test frequency can be reduced, the development cycle can be shortened, development cost can be saved, the design quality of a centrifugal pump can be effectively improved, an interpolation method is used between a fluid mesh and an acoustics mesh, sound source information of flow field calculation can be reserved to the maximum degree, GREEN analysis is used, the contribution degree on noise from different parts of a shell body can be obtained, such study is carried out, and early design or later modifying of the shell body can be optimized.

A Lamb wave resonator includes a piezoelectric layer, and a first electrode against a first face of the piezoelectric layer. The first electrode includes fingers and a contact arm, with each finger including a first side in contact with the contact arm and two other sides parallel to one another. Portions of the piezoelectric layer are at least partially etched between the two fingers to form a recess. The fingers are spaced apart from one another by a distance W calculated according to the following equation:

where,

va_lateral is an acoustic propagation speed of Lamb waves,

• • n is an order of a resonance mode of the Lamb waves,
  • f is a resonance frequency of the Lamb wave resonator.

The invention provides a shallow sea target depth classification method based on a hydrophone array. Detection is performed by integrating information received by multiple hydrophones, a typical probability density function of energy field change produced by model-based deep and shallow sound sources is generated by acoustic propagation simulation, likelihood ratio test (LRT) is performed based on the probability density function to identify a received signal, prior knowledge is extracted according to the law of distribution of sound energy within the whole range of a sound field, and thus, depth classification is performed on the sound field target. The algorithm is easy to implement and high in environmental adaptability.

A non-contact signal propagation property evaluation system for ropes can be deployed for a number of different applications including, but not limited to, moving lines, e.g., crane or winch and static lines, e.g., mooring lines, stays, etc., to evaluate physical properties of the ropes and, in some cases, to help evaluate structural health of the ropes. The system includes a first transducer for generating ultrasonic waves, a second transducer for receiving ultrasonic waves propagated transversely through and around the rope, and a processor executing computer readable code to determine acoustic propagation properties of the rope.

The invention relates to a method for obtaining a sonar operating distance index in a practical use environment. The method comprises the steps of calculating acoustic condition parameters such as sea area sound velocity, sea depth and sea bottom, the depth of an objective sound source and the depth of a sonar array by a sound field propagation model, wherein the acoustic condition parameters such as the sea area sound velocity, the sea depth and the sea bottom, the depth of the objective sound source and the depth of the sonar array are described in an original sonar operating distance index condition, obtaining an acoustic propagation attenuation curve TL0 under the original index condition, bringing a sonar operating distance index value R0 into the acoustic propagation attenuation curve TL0, correspondingly obtaining a high-quality factor FOM0 under the index condition, calculating a difference value between a practically measured objective radiation noise lever SL1 and an objective radiation noise level SL0 described in the original index, and a difference value between a practically measured background noise level NL1 and a background noise level NL0 described in the original index, obtaining a sonar high-quality factor FOM1 under a practical use condition, wherein the FOM1 is the sum of FOM0, delta SL and delta NL, bringing the sonar high-quality factor FOM1 into an acoustic propagation attenuation curve TL1 in the practical environment, and correspondingly obtaining a sonar operating distance index value R1 under the practical use condition.

The invention discloses an aspheric focus method of using an ultrasonic probe to transmit pulse. The method comprises the following steps: A1. arranging M/2 focuses on the centre line of the acoustic propagation direction of the center bore of the ultrasonic probe, wherein M represents the array number of the transmitting aperture of the probe; A2, calculating the transmitting delay, corresponding to the center bore, of each array of the ultrasonic probe, wherein arrays are focused to the focuses; and A3, controlling the pulse transmitting sequence of each array of the ultrasonic probe according to the transmitting delay. The aspheric focus method of using the ultrasonic probe to transmit pulse focuses the transmitted pulse on a continuous area during primary emission, the sound field on every point of the scanning line within a certain range has better directivity and the flutter fading of the sound field distribution can not caused when the sound field is away the focuses, thus the ultrasound image has more uniform resolution and brightness.

A pipe support for dampening acoustic propagation from a pipeline is provided. The pipe support can include a support base and a movable base spatially arranged from the support base. One or more fasteners can be disposed through the movable base to the support base, thereby connecting the movable base to the support base. One or more acoustic isolators can be disposed between an upper surface of the support base and a lower surface of the movable base.

An optical ultrasonic microphone includes an acoustic waveguide that transmits a sound wave received from an opening, an optical acoustic propagation medium that forms at least one portion of a wall face of the acoustic waveguide and an LDV head, and a sound wave proceeding through the acoustic waveguide is received by the optical acoustic propagation medium so that a change in the refractive index caused by the proceeding sound wave inside the optical acoustic propagation medium is generated with high efficiency, and by detecting this as an optical modulation by the LDV head, the optical ultrasonic microphone is allowed to have a very wide band.

An exemplary speech presentation system receives a simulated binaural audio signal associated with a media player device that is presenting an artificial reality world to a user. The simulated binaural audio signal is representative of a simulation of sound propagating to an avatar representing the user within the artificial reality world. The speech presentation system further receives acoustic propagation data representative of an aspect affecting propagation of sound to the avatar within the artificial reality world. Based on the acoustic propagation data, the speech presentation system extracts an auto-transcribable speech signal from the simulated binaural audio signal. The auto-transcribable speech signal is representative of speech originating from a speaker within the artificial reality world. Based on the auto-transcribable speech signal, the speech presentation system generates a closed captioning dataset representative of the speech and provides the dataset to the media player device. Corresponding methods and systems are also disclosed.

The invention discloses an underwater sound field numerical simulation method and system based on a Chebyshev polynomial spectrum and a medium. The method comprises the following steps: establishing asimplified control equation of an acoustic propagation Helmholtz equation under a cylindrical coordinate system; completing independent variable transformation from a z coordinate to an x coordinateby using the simplified control equation; implementing Chebyshev forward transformation on the simplified control equation, and mapping a physical space to a spectral space to form a discretized linear equation set in the spectral space; solving the discretized linear equation set in the spectral space to obtain a solution in the spectral space; implementing Chebyshev inverse transformation on thesolution in the spectral space, and mapping the solution in the spectral space back to the physical space; completing independent variable inverse transformation from an x coordinate to a z coordinate to obtain u (r, z), and solving a sound pressure field p; calculating propagation losses. The method is suitable for obtaining higher calculation precision under the condition that few discrete gridpoints are used, the calculation performance of a hardware platform can be brought into full play, and the speed of numerical simulation is remarkably increased.

The invention relates to an audio signal processing apparatus (100) comprising a determiner (101) being configured to determine a filter matrix C on the basis of an acoustic transfer function matrix H and a target acoustic transfer function matrix VH, wherein the acoustic transfer function matrix H comprises transfer functions of acoustic propagation paths between loudspeakers and a listener and the target acoustic transfer function matrix VH comprises target transfer functions of target acoustic propagation paths, wherein the target acoustic propagation paths are defined by a target arrangement of virtual loudspeaker positions relative to the listener, a filter (103) being configured to filter the input audio signal on the basis of the filter matrix C to obtain filtered input audio signals, and a combiner (105) being configured to combine the filtered input audio signals to obtain output audio signals.

The Ultrasonic Tomographical method and system is provided using measurements of time of flight low frequency acoustic waves. Differences in first signal arrival times from plurality of known transmitters' locations to plurality of known receivers' location are used, wherein the transmitters and receivers are at an angle to the surface of the observed object. 3D mapping of the acoustic propagation speed is reconstructed, revealing anatomical details and physiological properties.

The invention discloses a seabed petroleum pipeline leakage point positioning method based on sound line compensation. The method comprises the following steps:: deploying a plurality of underwater sensor nodes with a pH value sensing function and a plurality of underwater robots with a moving function at a given seabed pipeline monitoring area, and deploying four static buoys on the water surface; setting a pH threshold for the underwater sensor detecting petroleum leakage to be PL, and detecting the pH value of the petroleum pipeline, when the pH value is lower than the threshold value PL, indicating that the petroleum leakage occurs, and conversely, carrying out periodic detection; after the leakage occurs, sending a request positioning pulse to the underwater robots by the underwater sensor nodes, carrying out a time stamp information interaction process between the underwater sensor nodes and the underwater robots; establishing a water acoustic propagation time difference equationbetween the underwater sensor nodes and the underwater robots, meanwhile, considering an acoustic line bending effect in the underwater environment, establishing a leakage points optimization problemunder the acoustic line bending effect and solving the leakage points optimization problem, and completing the accurate positioning of the leakage points.