Symbolic generation of devoted simulators for non-linear circuits

Symbolic approach to the analysis of analog electronic circuits permits to obtain network functions in which all or some elements of the network are represented by symbolic parameters. The symbolic form of network functions is useful to inquire into the internal influence of single components onto circuit behaviour and gives also the possibility of quickly repeating numerical simulations on a given circuit topology, with different component or input signal values. Starting from previous considerations a new MS- DOS program which exploits symbolic analysis to generate simulators for linear and non- linear circuits has been developed by the authors. The program, named S Y M A N P L E C (SYMbolic ANalysis of Piecewise Linear Electronic Circuits), is able to generate simulators devoted to any part of the considered circuit. These simulators are independent programs, that work on numerical data in the time-domain. We could consider these devoted simulators like the output of the symbolic simulation part of the program, that is able to create network functions written in a Csource- code form file. The corresponding object-code is linked together with an object code that implements the Katzenelson algorithm . This is a classic iterative process that yields the DC solution of a resistive network including PWL elements. In the use of this algorithm the symbolic approach plays its fundamental part, allowing us to evaluate at each iteration step a single expression instead of solving a linear system .