A new approach to the exact design of LDI lattice digital filters

This paper presents a new approach to the exact design and synthesis of lossless discrete-integrator (LDI) lattice digital filters. The proposed approach is based on a discrete-time prototype reference filter which consists of a symmetrical lattice two-port network inserted between equal resistive source and load terminations, where the constituent lattice two-port network consists of LDI reactances as its canonical impedances. The salient feature of this prototype reference filter is that it permits the main important steps in the lattice digital filter synthesis to be performed directly in the discrete-time z-domain in terms of the LDI monomial. An example is given to illustrate the application of the proposed method to the design of an LDI lattice digital filter having a third-order elliptic lowpass magnitude-frequency characteristic