connecting DAC to SnP block

Hi all,

I am having trouble linking the DAC block to the SnP block. I have a .mdf file that has a list of SnP files which is being accessed by the DAC and then the data accessed by the DAC has to be sent to the SnP block to plot the data. I get an error in this last step. It says that an error occured while reading the data. Please help me out why this could be happening.

Thank you.

You cannot alter the filename parameter of an SnP component during runtime. It's frozen at pre-processing stage of the simulator run.
SnP is not treated as a "dynamic" component during core simulator run-time.(The same reason why you cannot change the resistance of an R component based on frequency. You don't get an error in case you try, but R simply won't adapt due to freq. It sticks with the value of the first iteration. R as a function of freq requires an eqn-based linear Z1P, which is treated as a varying element.)

The good news:
That's exactly what the Batch controller is good for! It's like a higher order (less efficient) sweep controller working outside the preprocessing stage.
(in contrast, regular parameter sweep loops post/inside pre-processing for performance reasons -> fast sweeps). This way, you can alter the filename, since the pre-processing is repeated for each iteration.

Have fun,
Toby

Toby on Sep 25, 2015 10:57 AM

Hi Toby,
Thanks for the reply. So do you recommend any other way of doing this? I have a ton of SnP files that I need to plot and I don't want to do it one by one. That is why I tried this method. I also tried a txt file with an index and the file names (as shown in example Amp1 under Dataaccess_wrk). That didn't work too. Now after what you said, I dont think it is going to be possible this way. Is there any other solution to this problem?
Thank you.

This Knowledge Center example may be useful: http://edadocs.software.keysight.com/display/eesofkcads/How+to+convert+many+s2p+files+into+datasets+using+batch+processing

Also, within the KC there are other examples/documents that go over processing multiple SNP files.

I don't have permission to view that file. I have been trying for a while and also requested capability but no luck yet.

What are the examples you mentioned?

Thank you so much for the help!

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Hi Toby,

What I am doing right now is using the Batch simulation component and a DataFileList component. I am sweeping the datafilelist using the batch simulation and then I am specifying the S3P file names in the datafilelist. But I am not able to set DataFileList1.FileName in the Snp block. Am I doing anything wrong?

Thanks.

> You cannot alter the filename parameter of an SnP component during runtime. It's frozen at pre-processing stage of the simulator run.
> SnP is not treated as a "dynamic" component during core simulator run-time.

Hi Toby,

actually you *can* create dynamic file names from variables, as I had shown here:

https://community.keysight.com/message/72543#comment-72543

Using a batch sweep is another possibility.

Best regards
Volker

Hi Volker,

does your proposed solution work nowadays? Did you verify that the utilized S-parameter files are acutally changing?

Before they introduced the Batch controller (years ago), your proposed solution didn't work, and that's probably the reason why they introduced the Batch controller. I've tried it exactly the same way you proposed many many times (deriving the filename dynamically based on a sprintf() call), and it didn't work in the past. You don't get an error and the filename variable does actually change, but the S-Parameter component sticks with the filename is got passed during pre-processing (initial simulation startup). (Similar to what you get from an resistor component R with a resistance based on an expression contraining freq. No error, but no frequency dependency either ;-)

Would be great if SnP components are now treated as "dynamic elements" - partially. It cannot be down to atomic level (freq/time), since you simply cannot change the S-parameter data defining a convolution kernel in time domain dependent on the time step. That's nonsense.
But maybe the now allow a re-eval on parameter sweep level. Could you please confirm?
Do you happen to know when they changed this (which ADS release)?

Regards,
Toby

> Hi Volker,
>
> does your proposed solution work nowadays? Did you verify that the utilized S-parameter files are acutally changing?

Hi Toby,

yes, I often use that method to sweep over different S-parameter files. From what I remember, I first tried with ADS2012 and it worked.

Best regards
Volker

附图/附件

sweepsnp.PNG

Good to know.
Thanks

Hi all,

I found a way out of the mess. I used the Batch sweep, a DAC with a .txt file of all the file names and the SnP block to read files from the DAC. It is working perfectly. Thanks everyone for the help. I really appreciate you guys taking some time off to help me! Thanks!

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