LISIM-simulator for time domain simulation of lossy transmission line systems in a nonlinear circuit environment

A program for the computation of signal propagation on coupled lossy transmission-line systems, called LISIM, is presented. Since most line systems are driven by nonlinear circuits (e.g. CMOS inverters), the program works in the time domain. The kernel of LISIM is a new algorithm for very fast and accurate simulations of large lossy line systems. In order to handle nonlinear circuit environments, a special partitioning technique called physical motivated partitioning by lines (PPL) was applied. The motivation for applying PPL is the fact that different types of descriptions are necessary for line systems (described by partial differential equations) and networks (described by ordinary differential equations). Compared to general-purpose network-analysis programs, LISIM requires significantly less simulation time and does not tend to instabilities. From a comparison with SPICE it was found that LISIM operates about 200 times faster on the average