Decomposition of a soundfield into spherical harmonics is a fundamental problem in acoustic signal processing. This paper shows how to design non-spherical microphone array structures in 3D space to decompose a soundfield into spherical harmonic components. We use the mode limiting property of the Bessel functions and zeros of the associated Legendre functions together with orthoganality of the...

The propagation of a pulse in a nonlinear array of oscillators is influenced by the nature of the array and by its coupling to a thermal environment. For example, in some arrays a pulse can be speeded up while in others a pulse can be slowed down by raising the temperature. We begin by showing that an energy pulse (one dimension) or energy front (two dimensions) travels more rapidly and remains...

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...

This paper, electronic resonant ballast for a small photovoltaic powered street lighting system in remote rural area was proposed. The street lighting system was designed for rural area where the electrical transmission line cannot be commonly serviced and it is the cascade systems of the solar arrays, switching battery charger, and electronics ballast with small fluorescent lamp. The ballast i...

Efficient nonlinear frequency conversion, such as second-harmonic generation in ultracompact structures, is essential for the development of modern nanophotonic devices. Here, we demonstrate intense emission scalable embedded Ag nanoparticle arrays fabricated by ion implantation into BK7 glass. The interparticle coupling effect significantly enhances local field at nanogap (gap size ? 1 nm) two...

We address two-dimensional (2D) waveguide arrays where light tunneling into neighboring waveguides may be effectively suppressed by an out-of-phase harmonic modulation of the refractive index in neighboring waveguides at suitable frequencies. Genuine 2D features, such as anisotropic diffraction engineering, diffraction-free propagation along selected directions in the transverse plane, and tunn...

We study many properties of Cauchy numbers in terms of generating functions and Riordan arrays and find several new identities relating these numbers with Stirling, Bernoulli and harmonic numbers. We also reconsider the Laplace summation formula showing some applications involving the Cauchy numbers.

Antenna arrays are of perennial interest and relevance to RF wireless system designers, indeed the rise of 5G is showing their importance is only growing. Most implementations of linear arrays use phase shifters to feed the array and hence form the main-lobe beam. In the 1960s, a technique using RF switches and Fourier analysis was discovered to be a viable alternative to phase shifters called ...