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Design Languages >> Verilog-AMS >> tolerances in the cross function
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Message started by jmith on Sep 26^th, 2011, 10:02am

Title: tolerances in the cross function
Post by jmith on Sep 26^th, 2011, 10:02am

Hi,

How should handle the simulator the situation when the current and previous values vioalates the tolerance parameters: show an error message or ignore the event generation?

Thanks

Title: Re: tolerances in the cross function
Post by Geoffrey_Coram on Sep 28^th, 2011, 1:44pm

If I'm understanding your question correctly, the simulator should reject the timestep and choose a smaller one, such that the tolerances are met.

Spice simulators frequently reject timepoints -- they're trying to take the largest step they can, so as to finish the analysis faster, and often take too big a step such that they fail to converge or don't follow the shape of the waveform accurately.

Title: Re: tolerances in the cross function
Post by jmith on Sep 28^th, 2011, 3:34pm

This is the same for ddt(expr, abstol)?

Title: Re: tolerances in the cross function
Post by Geoffrey_Coram on Oct 7^th, 2011, 7:37am

Yes, if the abstol isn't met, the timepoint should be rejected and a smaller step taken.