Re: [ng-spice] Readline Response
On Wed, 25 Aug 1999, Michele Quarantelli wrote:
> Traditional transient analysis is based on a direct integration
> of circuit equations using some kind of BDF. This approach definitively
>covers
> most of the designer's need. However, when dealing with high frequency (>
> 100Meg) systems where signals with very different time scales exist the
> analysis has to be carried out with a very fine time-step to "catch" the
> fastest signal and long enough to cover the entire low frequency signal
> spectrum (e.g. a mixer working at 900meg downconverting a 200k signal).
> The traditional approach in this case doesn't fit very well ...
> Different algorithms have been developed to solve the time domain steady
>state
> condition of a circuit and I mentioned some of them up above ... I'm sure
>you
> have heard of commercial simulators like Spectre, Harmonica, etc ... which
> implement some of the above algorithms.
> It would be nice to have some of them included ...
Yes, have heard of them but never used Spectre or Harmonica and do not
know the algorithms you mention, someone else knows them ?
> A final note: I'm currently comparing the last release of Berkeley Spice
> (spice3f5fix) against ng-spice. During op simulation of a LNA amplifier
> (including a grounded MOS device as a capacitor) I saw ng-spice converging
>to
> the wrong solution (i.e. vds not equal to zero) !!! I was using MOSIS
>BSIM3v1
> model so I re-compiled the bsim3v1 code (with some modification ... of
>course)
> and ... same result !!! At this point I'm quite concerned with ng-spice
> reliability ... Anyone having the same problem ?
ng-spice reliability is still to be tested. We changed the code in various
parts, and probably exploited an hidden bug (or inserted a new one). Can
you send to the list the netlist and modelcards so that we can perform our
simulations and try to discover the bug ?
Anyway: did you compiled in the bsim3v1 code included in spice3f5fix or
another one ? I had the same problem linkng all three B3SOI models in a
single executable: the PD model did not converged for one test circuit,
while the spice compiled with the PD model only converged. May be I have
not understood something in device code.
> Also how do I access the develpment release ? I tried anonymous cvs but it
> didn't work .
the login is anonymous and password: guest
you need to: export
CVSROOT=:pserver:anonymous@ieee.ing.uniroma1.it:/var/services/cvsroot
then launch the command:
cvs login
if it does not works, try:
cvs -d :pserver:anonymous@ieee.ing.uniroma1.it:/var/services/cvsroot login
you will be requested for a password: guest,
and then you can do your job (there is no confirmation for the login
procedure).
Paolo
Partial thread listing:
- Re: [ng-spice] Readline Response, (continued)