Differential equations of Mixed-systems modeling and simulation based on VHDL-AMS

Differential equations are indispensability way for modeling and simulating Mixed-Signal systems. Languages which are directly supporting the modeling of the Mixed-Signal systems are developed recently. VHDL-AMS is the standard of IEEE1076.1-1999. It is a powerful too for simulating numeric systems, analog systems, Mixed-Signal systems. The article discusses the elements syntaxes and the way how to model the differential equations. The emphasis is on how to change the partial differential equations which the VHDL-AMS does not support directly to the differential and algebraic equations.