If you look at real values
in a mixed signal simulation as representing continuous
electrical quantities, then:
X => can't compute a solution (voltage sources in parallel,
current sources in series, etc)
Z => no defined impedance associated with this branch
(floating (if current-driven) or
grounded (if voltage-driven))
I think Scott stated the question well - it makes little sense to
discuss the representation
until there is a clear idea of what sort of behavior one is trying
to model using real values.
It would be interesting to consider what sort of behavior(s) that
real-valued variables should
be modeling at mixed-signal interface(s) rather than in one domain
or other. It seems to me that
any useful behavior involves more than can be expressed in simple
scalars without trickery
involving magic values. (In other words, I agree with the position
that 'undriven', for example,
is information that should not be expressed by trying to encode it
into the real value of the driver
or other entity).
--ian
----------------------------------
Ian M Wilson
Architect
Berkeley Design Automation
Office: 408-496-6600 x238
Cell: 714-272-7040
ian.wilson@berkeley-da.com
http://www.berkeley-da.com
----------------------------------
True SPICE accuracy, 5X-20X faster
Don't Be Left Behind!
----------------------------------
--
This message has been scanned for viruses and
dangerous content by
MailScanner, and is
believed to be clean.
Received on Thu Dec 9 09:50:29 2010