Multidimensional digital ladder filter realization by spectral transformation

A straightforward approach to the ladder realization of multidimensional (M-1) recursive digital filters is presented. This approach consists of applying M-D spectral transformations to a stable 1-D digital ladder structure which is derived from a given passive lossless analog prototype. The stability of the resulting M-D structure then reverts to that of ensuring that the M-D spectral transformation is stable. Moreover, the ladder nature of the resulting M-D structure will preserve the low-sensitivity properties of its 1-D generating network. The method spans on the technique for digital design of 2-D doubly terminated LC structures and is based on the derivation of digital spectral transformations.<>