11 results about "Radiation impedance" patented technology

A reactive filter assembly comprising a reactive filter acoustically coupled to a transducer operable to generate an audio frequency by air nonlinearity demodulation of an ultrasonic frequency, wherein the reactive filter has a number of acoustic passes set to provide the transducer with a radiation impedance to improve the transducer efficiency.

A reactive filter assembly comprising a reactive filter acoustically coupled to a transducer operable to generate an audio frequency by air non-linearity demodulation of an ultrasonic frequency, the reactive filter having a number of acoustic pathways tuned to introduce a radiation impedance to the transducer that improves transducer efficiency.

The invention discloses a finite box rectangular horn shape optimization method and system based on a hybrid model, and the method comprises the steps: carrying out the geometric discretization of a rectangular horn in the axial direction into rectangular pipeline sections which are connected end to end, and determining a to-be-optimized design variable; pre-calculating a radiation impedance matrix and a far-field directivity primary function vector under a finite box body by adopting an external radiation model; calculating an inlet impedance matrix and a speed transmission matrix of each rectangular pipeline section on the basis of a radiation impedance matrix and a current design variable by adopting a sound transmission model in the horn, obtaining a mouth output speed vector, and solving an acoustic performance index in combination with a far-field directivity primary function vector; and constructing a comprehensive objective function, and solving to obtain a finite box rectangular horn shape optimization scheme. According to the method, the edge diffraction and sound reflection effect in a limited box environment can be accurately simulated, and the radiation efficiency optimization and directivity control of the broadband of the rectangular horn are realized while the calculation cost is remarkably reduced.

The invention relates to the technical field of voice generation, in particular to a personification voice generation method and system for a carry-on AI partner, and the method comprises the following steps: collecting an external environment sound simulation signal through a carry-on equipment microphone array, obtaining an environment acoustic harmonic feature set, storing the environment acoustic harmonic feature set, and obtaining a voice simulation signal; and obtaining environment frequency spectrum characteristic data. According to the method, after a sound channel regular curled spectrum sequence is subjected to time domain smoothing to form frequency domain curled modulation data, a high-frequency-band spectrum envelope interval is extracted, amplitude gain improvement is executed according to a lip radiation impedance coefficient, then the frequency domain curled modulation data is superposed, and anthropomorphic interaction voice signals are generated. And high-frequency friction and gingival blasting details are enhanced without damaging the overall spectrum continuity, the environmental suitability, the anti-interference stability, the formant controllability and the high-frequency detail intelligibility, so that a chain gain is formed.

The invention relates to a device (10) for detecting the movement of a person (2) using microwave waves for a motor vehicle (1), said device (10) comprising a radiating impedance module (110) configured to be powered by a DC power supply (30) and including a detection antenna (112), a MOSFET-type transistor (114), and an impedance adapter (116) forming a closed-loop electrical circuit oscillating at a predetermined fixed frequency when said circuit is powered by the voltage supplied by said DC power supply (30). Figure 2

The invention discloses a structural dry-wet response conversion and underwater noise calculation method based on an acoustic impedance matrix, and the method comprises the steps: obtaining the vibration mode of an overall structure, obtaining a mode shape matrix, carrying out the forced response test of the overall structure, and obtaining the node vibration response of the overall structure. A modal participation coefficient is calculated through inversion or a regularization method, a modal with the modal participation coefficient being 0 is eliminated, response expression is updated, an immersed surface acoustic radiation impedance matrix is calculated, a modal participation coefficient vector after immersion is calculated, underwater vibration response of the structure is calculated, and underwater acoustic radiation is calculated according to immersed surface vibration response distribution and an acoustic radiation acoustic resistance matrix. According to the vibration response of the structure in the light medium and the acoustic impedance matrix of the underwater immersion surface of the structure, the prediction of the underwater vibration response and sound field distribution of the structure is realized; the method can overcome the problems of high difficulty in underwater testing, low fluid-solid coupling calculation efficiency and the like, and is a new method for conveniently and efficiently obtaining the underwater vibration sound response of the structure.

This utility model relates to the field of composite panel structure technology, specifically a sound insulation and vibration reduction partition for ship cabins containing acoustic black holes. The partition includes: an acoustic black hole thin plate layer, a damping material layer, and a honeycomb panel layer. Multiple sets of acoustic black hole structures are arranged in an array on the acoustic black hole thin plate layer, and the thickness of the acoustic black hole region satisfies a power law. The damping material layer forms an energy buffer interface, and its two sides are connected to the acoustic black hole thin plate layer and the honeycomb panel layer, respectively. The honeycomb panel layer is used to complete acoustic radiation impedance matching and suppression. This utility model constructs a complete acoustic vibration control chain of "vibration capture - energy dissipation - acoustic impedance matching" through gradient impedance design of each functional layer, improving sound insulation without increasing mass. It is particularly suitable for applications such as ship cabins that are weight-sensitive and require broadband noise reduction.

The invention discloses a method for determining guided wave frequency dispersion characteristics of a liquid-filled steel riser, which is characterized in that three-dimensional guided wave propagation is equivalent to a radial one-dimensional intrinsic problem under an axial symmetry condition, a relation between a complex wave number and frequency dispersion can be obtained only by dispersing the radial direction, and high degree of freedom of three-dimensional modeling is avoided. Internal fluid is not coupled through additional boundary terms, and is merged into the overall system by adopting a section contribution matrix, so that fluid-solid consistent assembly in the same system is realized, and error sources of coupling inconsistency are reduced. An external infinite water area does not use an absorption layer for approximation, and external water is equivalent to a wavenumber-related damping boundary by using radiation impedance meeting an infinite radiation condition; and the self-consistent complex wave number is solved through linearization and inverse iteration, so that the radiation modeling accuracy and solvability are improved.

The invention belongs to the technical field of sound field calculation, and particularly relates to a sound field calculation method, program and equipment for an open cylindrical cavity embedded rigid spherical scatterer based on modal matching and spectrum expansion and a storage medium. Unified solution of intra-cavity scattering and outer domain radiation is realized through a column mode expansion and sphere-column wave function interchange relation, a mode radiation impedance matrix is constructed to eliminate an outer domain unknown spectral quantity by using a Somerfeld spectrum to naturally meet an outer radiation condition, and a numerical solution analysis framework is formed. According to the method, the calculation efficiency is remarkably improved while the geometric accuracy is guaranteed, and the method is suitable for sound field prediction and optimization design of a complex perforated structure, acoustic material and vector sensor integrated system.

The application discloses a tunneling light-emitting device based on barrier-mode field impedance matching and a modulation method thereof, comprising a substrate, an insulating tunneling layer arranged on the substrate, and a metal nano antenna array arranged on the insulating tunneling layer, wherein the metal nano antenna array is a periodically arranged metal strip array, and the geometric parameters of the metal nano antenna array and the electrical parameters of the insulating tunneling layer are cooperatively configured, so that, under the bias voltage of the tunneling light-emitting device, the differential tunneling resistance of the insulating tunneling layer and the equivalent radiation impedance of the metal nano antenna array at the excitation wavelength realize conjugate matching or mode value matching, so as to promote the efficient transfer of the tunneling electron energy to the optical mode; the advantage is that the critical coupling of the electron tunneling rate and the optical mode radiation rate can be realized, so that the electroluminescent efficiency is significantly improved, and the energy transmission efficiency is relatively high.

The invention discloses a frequency-adjustable wide-angle scanning phased-array antenna array, and the array comprises a plurality of phased-array antenna basic units which are arranged in a 2n * 2m array structure form. Each phased-array antenna basic unit comprises a wide-angle impedance matching layer, a medium supporting layer, a frequency-adjustable radiation unit layer and a slot etching ground feed layer which are sequentially connected from the top of the antenna to the bottom of the antenna; the wide-angle impedance matching layer comprises an impedance matching layer dielectric substrate and a first metal structure etched on the upper surface of the impedance matching layer dielectric substrate; the first metal structures are arranged in a planar array form; the first metal structure is used for adjusting radiation impedance during antenna beam scanning; the frequency-adjustable radiation unit layer comprises a radiation layer dielectric substrate and a second metal structure; the second metal structure is etched on the upper surface of the radiation layer dielectric substrate, and the second metal structure is an axisymmetric etching structure. The impedance matching characteristic of the antenna array can be adjusted, the reflection loss is reduced, and wide-angle scanning is realized.