منابع مشابه
Nearfield beamforming using nearfield/farfield reciprocity
We establish the asymptotic equivalence, up to complex conjugation, of two problems: (i) determining the near eld performance of a far eld beampattern speci cation, and (ii) determining the equivalent far eld beampattern corresponding to a near eld beampattern speci cation. Using this reciprocity relationship we develop a computationally simple procedure to design a beamforming array to achieve...
متن کاملOn nearfield acoustic holography
Such functions u are called radiating solutions. Pressure measurements are taken by acoustical sensors located in a domain Ω0 inside or outside the cabin or on a surface Γ0 = ∂Ω0 . Our goal is to reconstruct u inside Ω, or the normal velocity v = ∂νu on Γ = ∂Ω, (ν is the unit exterior normal to ∂Ω). This is a mathematical model of the nearfield acoustic holography [W], [Wu]. H(m)(Ω) denotes the...
متن کاملNearfield broadband adaptive beamforming
A nearfield broadband adaptive beamforming approach based on the modal expansion of the solution to the spherical wave equation is formulated. It provides an efficient parameterization for the nearfield beamforming problem with a single parameter to focus the beamformer to a desired operating radius and a set of modal coefficients to control the angular response. As a consequence, the adaptive ...
متن کاملNearfield binaural synthesis and ambisonics.
Ambisonic encodings can be rendered binaurally, as well as for speaker arrays. This process is developed for general high-order Ambisonic encodings of soundfields containing near as well as far sources. For sufficently near sources an error is identified, resulting from the limited field of validity of the freefield harmonic expansion. A modified expansion is derived that can render such source...
متن کاملOptical near-fields & nearfield optics
Optical methods provide exceedingly powerful tools in science and technology for measuring, analyzing and manipulating, from optical microscopy and spectroscopy to the characterization of ultrafast processes by femtosecond pulses and the modification of materials by intense laser radiation. However, when it comes to applications in the nanometer-regime, the conventional optical techniques suffe...
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ژورنال
عنوان ژورنال: Optics Express
سال: 2019
ISSN: 1094-4087
DOI: 10.1364/oe.27.032019