Study of phase symmetry in 3-D filters

Various symmetries and antisymmetries that can be present in the phase responses of a 3-D filter are defined. The nature of constraints that are imposed by these defined symmetries on analog and digital polynomials in their phase responses are then discussed. It is shown that the symmetries considered are preserved by a bilinear transformation operation. This is illustrated by taking 2-D quadrantal symmetry as an example.<<ETX>>