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Simulators >> Circuit Simulators >> Insert complex impedance in Spectre.
https://designers-guide.org/forum/YaBB.pl?num=1185873636

Message started by Mosieur_Oiso on Jul 31^st, 2007, 2:20am

Title: Insert complex impedance in Spectre.
Post by Mosieur_Oiso on Jul 31^st, 2007, 2:20am

Hello,
Is there a way to insert a complex impedance in Spectre Z=R+jX without using caps or inductors? If not, how can I insert a delay line for pss simulation? (simulation always fails when using tline from analogLib)
Thanks

Title: Re: Insert complex impedance in Spectre.
Post by ponymony on Jul 31^st, 2007, 3:44am

Hello,

I have also tried to simulate a delay line in pss simulation with VerilogA "absdelay" but with no success.
Error message:

Error found by spectre during periodic steady state analysis `pss'.

The component for_uri_delay is not supported in PSS analysis because it is a behavior module component with hidden states. Components with hidden state are not allowed with

this analysis -- analysis skipped.

Title: Re: Insert complex impedance in Spectre.
Post by Geoffrey_Coram on Jul 31^st, 2007, 5:26am

Mosieur_Oiso wrote on Jul 31^st, 2007, 2:20am:

Is there a way to insert a complex impedance in Spectre Z=R+jX without using caps or inductors? If not, how can I insert a delay line for pss simulation? (simulation always fails when using tline from analogLib)

R+jX is non-physical, unless you're also adding R-jX. You might be able to use a dependence source with num,den polynomials.

Title: Re: Insert complex impedance in Spectre.
Post by Andrew Beckett on Aug 27^th, 2007, 2:12pm

You can use "mtline" these days in PSS - so you could try that.

As Geoffrey points out, a complex impedance is non-physical, and so simulating that in the time domain would be non-causal - and would present all sorts of trouble for the poor simulator. So you can't directly do it. It is possible these days to specify a port with complex impedance, but there was a problem with doing this in the RF analyses (even in harmonic balance) - I don't know whether this has been resolved yet (I've not checked).

Regards,

Andrew.