RE: initial_step for ac analysis sweeping voltage

Hi Geoffrey,

Wouldn't this apply to any nested sweeps -- only for the innermost sweep the OP would be calculated once. In the case of an AC analysis where the frequency is not being swept this would become down to a degenerate case where the innermost sweep has only 1 sweep value.

I do agree that an additional statement here could help, but put it in the structure of nested sweeps as a general rule, instead of AC as a specific rule. Anyway, it would also apply to noise analysis.

By the way: should we extend the current list of analyses with RF type analyses, i.e. PSS, PAC, HB? I'm not sure anything special needs to be done for this ...

Cheers,
Marq


Marq Kole
Product Manager Robust Design
NXP Semiconductors / Corporate I&T / Design Technology & Flows


-----Original Message-----
From: owner-verilog-ams@server.eda.org [mailto:owner-verilog-ams@server.eda.org] On Behalf Of Geoffrey.Coram
Sent: Wednesday 22 October 2008 15:54
To: VerilogAMS Reflector
Subject: initial_step for ac analysis sweeping voltage

I'm looking at Table 5-1 on the return values of initial_step,
and I think there's still an ambiguity for ac sweeps where
frequency is not the variable being swept.

The header for the AC column says "OP p1 PN" and the
initial_step return values are "1 0 0"

If you do an AC sweep where you sweep voltage, then the
simulator has to compute the OP for each point of the sweep.
So, does initial_step return 1 for each point, because it
is supposed to return 1 for the OP, or 0 because there are
0s under p1 and PN?

-Geoffrey

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