Getting data from an "intersect"

Dear Chris,

CSCNalu said:

I want to know where two waveforms from an ADE sim intersect so I used the "intersect" command but how do I access the values of the coordinate pair? 

Did you happen to try the xval() function on the resulting intersect operation? For example, in Figure 1, I show two waveforms (divout_p and divout_n) that intercept twice every waveform period.  I use the following Calculator intersect expression and plot the result in Figure 2:

intersect(leafValue( VT("/divout_p") "freq_GHz" 16 ) leafValue( VT("/divout_n") "freq_GHz" 16 ) )

In Figure 3, I then apply the xval function to the result with the Calculator expression and plot the result in Figure 3. There are many waveform intersections and hence the result appears as a waveform. Alternately, you could append the result to a table or select the waveform in Figure 3 and export it. Since the waveforms intersect at the same timepoints the x and y coordinates of the waveform are identical.

xval(intersect(leafValue( VT("/divout_p") "freq_GHz" 16 ) leafValue( VT("/divout_n") "freq_GHz" 16 ) ))

I hope I understood your question and this example is somewhat relevant and helps you Chris.

Shawn

Figure 1

Figure 2

Figure 3

Hi Shawn

Thanks - yes - that's mostly what I was looking for.  Is there a way to pull off the first value?  I want to use this as a threshold for subsequent measurements.

Chris

Dear Chris,

CSCNalu said:

Is there a way to pull off the first value?  I want to use this as a threshold for subsequent measurements.

Please try the following in the calculator using my prior waveform expression as an example:

drGetElem(drGetWaveformXVec( xval(intersect(leafValue( VT("/divout_p") "freq_GHz" 16 ) leafValue( VT("/divout_n") "freq_GHz" 16 ) )) ) 1)

Basically, this creates a vector from the waveform of intersecting times using its "x" component. The function drGetElem() takes the resulting vector and returns the element you select from the vector. In my example, since you wanted the first value, I used "1".

I hope this manages to explain it well enough for you to try Chris.

Shawn

You could also just use the firstVal function in the calculator. That will get the first yVal, and so if you've used xval it will give the x-value. Hence:

firstVal(intersect(leafValue( VT("/divout_p") "freq_GHz" 16 ) leafValue( VT("/divout_n") "freq_GHz" 16 ) ))
firstVal(xval(intersect(leafValue( VT("/divout_p") "freq_GHz" 16 ) leafValue( VT("/divout_n") "freq_GHz" 16 ) )))

A bit simpler than messing around with drGetElem, plus I think they also work if the argument is a family waveform (the drGetElem approach may not do what you want).

Andrew

Hi Shawn, Andrew

Thanks!  Andrew's is simplest for this one but Shawn's tells me how to get other values that I didn't know how to get.  Thanks everyone!

Hi Shawn, Andrew

Thanks!  Andrew's is simplest for this one but Shawn's tells me how to get other values that I didn't know how to get.  Thanks everyone!

Dear Chris and Andrew,

I am happy to read, Chris, that you were able to understand my comments! I hope it solves your problem...and thank you, Andrew, for your added suggestion, I was not thinking of a family of waveforms so your comment was insightful for me!

Shawn