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getting the number of points in a waveform, or the number of events...

MarkGr15

I want to count the number of times an analog waveform crosses a threshold. It will do so , lets say 3 times, in a period in time (I am going to clip the time period in the Spectre calculator).

This is what I am trying, it creates a waveform (N time points, with associated values).

overCurrentXingsInClip1=cross(clip(VT("/fb_top1/I_buck_nonlinear/I0/overcurrent_det")  20u 40u ) 1.8/2 1 "rising"  t "time"  )

I want the number of time points.  Is there a way to get this?

The goal is to count the number of crossings, mind you. If there is another way to skin the cat, I'm open to that.

Thanks

Mark

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  • Andrew Beckett

    Hi Mark,

    Sorry, I didn't try your code, and so didn't notice that you had the "multiple occurrence" option set. Rather perversely, you need to have it set to "single occurrence" (which corresponds to having the last two arguments to the cross() function set to nil), and then it should work.

    The multiple occurrence feature was added at some point later, and will generate a waveform with all the crossing points - which would require you to use an approach similar to Shawn's suggestion, but if you use the older "single occurrence" capability, you can set the edge number to 0 and get a list of the crossings (which is normally not useful in the calculator because it can't deal with SKILL lists of stuff).

    So that should be:

    overCurrentXingsInClip1=length(cross(clip(VT("/fb_top1/I_buck_nonlinear/I0/overcurrent_det")  20u 40u ) 1.8/2 0 "rising" nil nil  ))

    Hopefully that will work for you!

    Regards,

    Andrew.

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  • Andrew Beckett

    Hi Mark,

    Sorry, I didn't try your code, and so didn't notice that you had the "multiple occurrence" option set. Rather perversely, you need to have it set to "single occurrence" (which corresponds to having the last two arguments to the cross() function set to nil), and then it should work.

    The multiple occurrence feature was added at some point later, and will generate a waveform with all the crossing points - which would require you to use an approach similar to Shawn's suggestion, but if you use the older "single occurrence" capability, you can set the edge number to 0 and get a list of the crossings (which is normally not useful in the calculator because it can't deal with SKILL lists of stuff).

    So that should be:

    overCurrentXingsInClip1=length(cross(clip(VT("/fb_top1/I_buck_nonlinear/I0/overcurrent_det")  20u 40u ) 1.8/2 0 "rising" nil nil  ))

    Hopefully that will work for you!

    Regards,

    Andrew.

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