Symmetry requirements for multidimensional digital filters
Alfred Fettweis · International Journal of Circuit Theory and Applications · 1977
Abstract Various methods for designing multidimensional digital filters exhibiting approximately circular, spherical or hyperspherical attenuation symmetry are discussed. It is shown how, by means of appropriate series expansions, symmetry requirements for filters with any number of dimensions can be fulfilled with arbitrary precision by adopting transformations of correspondingly increased degree. Some of these transformations are generalizations of the known McClellan transformation. Simple means for ensuring excellent symmetry at frequencies remote from the origin are presented.