Dolph-Chebyshev radial filter for the near-field spherical microphone array

When close enough to a microphone array, the spherical nature of radiating sources allows for sound field processing in terms of distance as well as direction. As part of an on-going study on beamforming given sources close to a spherical microphone array, sound field processing is examined through the use of radial filters. In this paper, a radial Dolph-Chebyshev design is presented for attenuating far-field interference given sources close to the array surface. The proposed radial filter facilitates an analytical formulation of the design technique, and may be practical for sources very close to the array surface.