Hi
1) AdVanceMS of Mentor is OK for mixed-signal modeling using VHDL-AMS
2) The time-efficiency gained when using MS-HDLs becomes apparent in catching errors early in the design cycle, in avoiding long SPICE simulations (transistor-level), less silicon respins...
3) This is of course a bit of an open issue..."who watches the watcher"?
I try to evaluate the behavior/correctness of my models
using:
a) intuition/common sense (e.g. opamp output should not shoot above the supply voltage)
b) mathematical formulae, relationships: does the model obey them?
c) based on design experience (if you ever designed e.g. an LNA, any weird behavior in your model will catch your attention. If you don't have design experience on a block you want to model, resort to papers or try to find someone who has experience with that block.
Kind Regards
Peter