I asked this question not for reaching to this Point:
MAKE the signal determinate
We can use from such condition for automatic fault detection
For example,Assume that particular section of a system
Can have such illogical signals,After reaching to such condition
This message appear,"The system have an internal error"
But andy if you use a schmitt trigger you never can find this error
so your system gives you 0 or 1 that it is not real value!
And terry,Maybe damaging an IC occurred,In this situation is it designers responsibility ?
Again probably,But some ic's have endurance period of time
And when it passed they haven't main characteristics
Thing that i wanted to say and then I started this thread is this:
Some times such illogical signals help us to having reliable systems!
Best Regards