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Simulators >> Circuit Simulators >> Saving operating point in Transient
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Message started by parth_sv on Feb 28^th, 2008, 5:45am

Title: Saving operating point in Transient
Post by parth_sv on Feb 28^th, 2008, 5:45am

Hi All,
I need to do noise analysis on a circuit whose response is quite dynamic. For this purpose i need to save the operating point of the entire circuit at a given time in transient run and use this as 'ic or nodeset' in noise analysis. While its quite easy in hspice, how can I do this in spectre(ADE) (Unfortunately I dont have access to hspice -:( )?

Thanks in Advance

Title: Re: Saving operating point in Transient
Post by achim.graupner on Feb 28^th, 2008, 6:39am

Hi there,

well the most simplest solution is using the final operating point.
In Cadence ADE this option is "hided" is in the Setup->Simulation->Transient->Option.

As far as I remember you need to do an DC op before the noise analysis, as in noise analysis nodeset has been or still is not supported.

To change the analysis order (to have dc before noise) in ADE it is Setup->Environment->Simulation Order, just use spectre syntax there.

Hope that helps,
Regards,Achim

Title: Re: Saving operating point in Transient
Post by John O Donovan on Feb 28^th, 2008, 9:05am

Do a spectre -h tran, and look at the parameters actimes and acnames. These allow you to run a set of AC type analyses, including noise at particular times during the transient analysis. I think that there are equivalent fields in the ADE interface but don't have ADE up to check.

Regards,
John

Title: Re: Saving operating point in Transient
Post by parth_sv on Feb 29^th, 2008, 5:01am

Hi John,
Thanks - got it. Need to specify acnames and actimes - time when i want to run noise