Maestro: Use Simulation sweep variable in output equation

I would guess that the xval function (with an arbitrary signal as argument) will do what you want.

Well, the variable is not a signal, its a variable that is used as a parameter in a schematic instance.

But I'll give it a try ...

Can you tell, how you are doing sweeps in Maestro ?

Are you always sweeping via DesignVariables instead of AnalysisVariables ?

The xval function gives you the x-axis value of the result, which I guess is what you want.

As Frank said, it doesn't matter what you are sweeping or how you are sweeping - the xval function gives you the x-axis versus itself for any waveform. So if you use xval(VS("/blah")) it will give the sweep variable for the DC sweep.

Whether you use a Design Variable sweep or a sweep in an analysis (presumably that's what you mean by "AnalysisVariables", a term I've never heard before) rather depends on precisely what you want to do - so I don't think it's something that can be generically answered.

Andrew.

Guys - you once again made my day !

Thats exactly what I was looking for !

Thanks a lot  ;-)))

Dear HoWei,

Please allow me to add a comment/question and a possible suggestion....

HoWei said:

I am doing a DC sweep on variable "Vgs". The variable is swept by the DC simulation from 0 to 1.0 - not via the tests DesignVariable.

The test DesignDariable is set to "0.99".

Now I want to use the swept variable in output equations via VAR("vgs") - but this gives me a constant of 0.99, and not the expected swept values.

Why is that and how can I access the swept variable ?

By any chance, do you have the Design variable "vgs" in your test defined as a Global variable (i.e., checked as a Global variable)?  If so, have you tried removing the check mark adjacent "vgs". With it unchecked as a Global variable, it seems as if Maestro will look in the test editor for its current value. With it checked, as you noted in your observation, the value will be fixed at 0.99.

Just a thought,

Shawn

Hi Shawn, 

nice idea - I tested it and what happens is:

Once unchecked the Global "vgs" it enables the DesignVariable "vgs" and the behaviour isthe same as before - only 0.99 is available via VAR("/vgs") in the output

On more question aside the problem: what does the checkbox next to the DesignVariable do ?

If I check it or not, I do not see any difference.

The checkbox for design variables only makes sense if you have the global variable enabled.

If you have the global variable unchecked, then the local (design variable) value is always used (and the checkbox is unnecessary and has no effect)

If you have the global variable checked, then normally the local (design variable) value is not used (there's a strikethrough through the design variable); if you check the design variable you can then enable the design variable value for that specific test whilst leaving the other tests to use the global variable.

I wouldn't have expected Shawn's suggestion to help in this case because the sweep is being done inside the analysis, and so the design/global value (which is what VAR() retrieves) is not what you want.

Regards,

Andrew.