Here's another one--

I am familiar with the function, GETVALUEAT. I even can select it from the help index in 2006. But there's no mention of it or its replacement in help.

Help?!

I am familiar with the function, GETVALUEAT. I even can select it from the help index in 2006. But there's no mention of it or its replacement in help.

Help?!

Many times we want to optimize isolation, defined as dBc. We used to be able to do this in post-processing, using the special function, GETVALUEAT. How do we do this in Genesys 2006?

Respectfully submitted...

We don't support GETVALUEAT in 2006 because it doesn't really make any sense in our context of having data. There are two interpretations of it, one as an index (for which we just use index) and one using an independent variable (for which we use the @ operator, like in 2004).

Can you give me a concrete example I can write in current equation code for you?

Mark

We're trying to compute dBc reckoned from a minimum in insertion loss. We want to optimize the stop band isolation of a filter and we can tolerate more passband insertion loss to achieve this goal.

I found the @ operator last night but I haven't figured out how to use it properly. (If this operator was available in 2004, then I never knew about it.)

I'm starting to see some of the wisdom in the new data structures, but I haven't learned enough about the new ways yet.

Thanks again for getting back on this.

MWI

Well, if you have insertion loss as IL from a linear analysis (with frequency sweep F), the equation would be

using("mylineardata") ' point to your dataset

IL=S[2,1] ' typical insertion loss formula

ILmin = max(IL) ' minimum insertion loss (max gain)

FMin = min(F[IL@ILmin] ) ' one frequency at the min insertion loss

ILdbc = db( ILmin) ' db at min insertion loss

Does this help? You might also want to take a look at the datasets tutorial video coming in the latest version (2006.07).

Regards,

Mark

I started watching the dataset video, and it is actually very interesting! (I usually blow off how-to movies because they aren't information-dense enough.)

Part of the problem (for me) stems from the fact that the internal workings of Genesys seem to be completely different from the past. So now I have to change all the circuits in the Genesys part of my brain!

We got a little ways on this, but we're not there yet. We want to *graph* dBc and optimize it. We also want to make sure IL (-dB(S21)) stays above the required value. If I get this sorted out I'll be sure and post back.

Thanks again, pal!

mwi

I figured it out, I think, and the answer is vastly simpler than I was trying to make it. (New users might not have even had the problem in the first place! ) The steps that worked follow:

1. I opened a *new* equation window to keep the definitions of circuit elements separate from the definitions of the desired output.

2. I entered the following syntax into the new equation window:

(I entered these lines one at a time so I could see what the results were in the left-hand side of the output equation window.)

3. I already had a graph of S[2,1] and S[1,1], so I clicked "Add Series" in the Graph Properties dialog box and entered the following syntax:

8)

This is *vastly* simpler than what we used to do in the olden days...

mwi

I just tried the following:

In the graph properties dialog box, I entered

Whoa!

Well, looks like it's starting to make sense... that's great. All of those constructs should work fine.

btw... You don't need that leading = in the graph series entry (we assume it's an equation) as far as I know. And I'm pretty certain that max(complex vector) is max( amplitude(complex vector)).

I'm terribly glad to hear you think that it's simpler than it used to be.

Mark Zachmann

The documentation says that "max" looks for the real part. I decided to test this with code and that is why I posted back with the extra syntax. Try it yourselves, you'll see that if you'll need to put in "abs" if you are looking for the magnitude extrema.

From a complex variables point of view, as well as a "What is the return loss?" point of view, it makes more sense to me to look for the largest *magnitude.* Que sera, sera, however.

Mark

Working with the new data structures is still way cool!

8)