A new insertion loss technique for the exact design of elliptic LDI ladder digital filters

Abstract

A new insertion loss technique is represented for the exact discrete-time z-domain design and synthesis of lossless discrete-integrator (LDI) ladder digital filters realizing elliptic transfer functions. In this technique, the entire LDI ladder digital filter synthesis is performed directly in the discrete-time w-domain (i.e. without any recourse to the concept of a continuous-time analog prototype reference filter), where w represents the LDI monomial. The proposed design technique is capable of realizing a wide class of other practical digital transfer functions, including the classical Butterworth, Tschebysheff, inverse Tschebyscheff functions as special cases. It lends itself in a straightforward fashion to the synthesis of the corresponding LDI lattice or other similar practical digital filter configurations. >