Modelling in VHDL-A

VHDL (IEEE Standard 1076) is currently being extended to include mixed-signal and analogue modelling (VHDL-A). A draft standard is expected in 1995. This paper describes two models developed in VHDL-A. One of the design objectives of VHDL-A is compatibility with SPICE, and, therefore, a version of the SPICE Level 3 MOS model has been written. The second model is of a phase-locked loop, including a VCO. As the standard is not complete, no VHDL-A simulators are available to verify these models. Nevertheless, it has been possible to investigate several important aspects of modelling with VHDL-A