The continuous-discrete interface - What does this really mean? Modelling and simulation issues

The arrival of VHDL-AMS opened a lot of doors for the mixed signal analysis community. For the first time, standardised and widespread interoperability has been made possible, and people from different organisations could sensibly exchange information and designs. However, this interoperability comes at a price. The structure of the language - of any language, human or computer, come to that - colours the thinking of those using it. This paper comments on a number of issues that are often ignored - if indeed they are acknowledged at all - when designing or describing mixed signal systems. It is qualitative, and aimed at users of automated design systems, as opposed to those who design the design systems.