VHDL-AMS is an extension of VHDL to design analogue systems. It was introduced in 1999 as IEEE 1076.1–1999 standard as Superset of VHDL IEEE 1076–1993. It supports modelling of continuous time-driven systems, discrete time-driven systems and mixed signal systems. VHDL-AMS has added features to digital VHDL standard IEEE1076–1993 in terms of object interfaces, behaviour, types, and attributes. It supports modelling of continuous time systems based on differential equations. The simulation kernel has a dedicated part called analogue solver, which does the computation part for differential equations.
VHDL supports the following modelling approaches: