.measure problem

[Rick &Dick (quizas)]

Hi there,

I'm trying to simulate a opamp using Xyce, but in AC analysis, .measure line seems couldn't resolve the parameter defined in another .measure line. For example:

in

.MEASURE ac ugf WHEN VDB(VO_AC)=0
.MEASURE ac phase MIN VP(VO_AC) FROM=1 TO='ugf'

it leads to:

Netlist error: Attempt to evaluate expression {ugf}, which contains unknowns

Simulation aborted due to error. 

Is there any method to solve this?

Thanks,
Rick

[xyce-users]

Hi Rick,

Unfortunately, at the moment I don't think there is a way for this to work in Xyce.  

When you put something inside of single quotes like this ('ugf'), that invokes the expression library.  The expression library can pull lots of information from Xyce (voltage nodes, .param values, etc), but it hasn't been instrumented (yet) to pull in .MEASURE values.  

However, I'm glad you brought this to our attention.  I think this is a feature that can be added, and I think it should be.  It probably should have occurred to me to make this work prior to now as the use of .MEASURE inside of expressions would be very useful in a variety of contexts.  

So, I will add this to our internal issue tracker.  I'm not sure when we'll get to it, but we'll do it.

thanks,

Eric