Re: multiple analog blocks

Ken Kundert wrote:
> ... run
> a transient analysis up to a certain point in time and then run an AC
> analysis. One might want to do this with adaptive filters, where
> transient analysis would be used to train the filter, and then an AC
> analysis is used to characterize the adapted filter.
...
> It is possible to perform these
> sequences in Spectre when using built-in components because Spectre
> allows the user to specify whether initialization should be performed on
> a particular analysis when specifying the analysis.

It seems to me that this is a simulator-specific question,
and Cadence/Spectre should take the initiative for determining,
for a particular analysis sequence, whether @initial_step is
going to be true.

For your specific case, you could use initial_step("tran")
or analysis("ic") to have initialization performed only for
the transient and not for the ac.

One also has analysis("nodeset") which I assume will not be
true at any point during the ac analysis that uses the 
transient operating point.  I think it's the simulator's job
to determine whether in Table 4-25 there is or is not an "op"
preceding the ac analysis.

I contend that there are plenty of "initialization" possibilities
in the language already, with initial_step("analysis")and the
various arguments to analysis(): "ic" "nodeset" "static"
Adding an "analog initialization" just adds something else
that has to be spelled out in the simulator documentation,
and the user has to read that anyway to determine whether
it is performed in the specific analysis sequences supported
by the simulator.

-Geoffrey

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.