Using a single port network anaylser to measure a differential system 1

[bpelec]

I have a single port network analyser (HP 8714B), but I need to perform a measurement on a differential system.

We had planned on taking each core of the differential system, and testing it relative to the shield using a single-ended measurement. However, our system has evolved to include a resistive network between the two cores of the differential pair in order to achive some impedance matching.

I think I am after some kind of Balun, but we need to test from around 300Mhz to 3Ghz.

Is there some standard way of using a single port network anaylser to measure a differential system?

Thank you for your help.

Best regards,

BPELEC.

 

[Skogsgurra]

I have used an HF transformer (Pulse Engineering type) to measure differential lines. But at much lower frequencies - around 1 MHz.

Gunnar Englund

http://www.gke.org

 

[bpelec]

Thank you for your reply skogsgurra, and I think your suggestion may well be the way to go.

I have found an application note from a company that makes transformers:

http://www.picosecond.com/objects/AN-8.pdf

The same company seems to make baluns that work over a very wide bandwith (about 200 kHz to 15 Ghz). This may well be a solution for me, and I am talking to the company.

However, if there are any other solutions out there, I would be very interested to hear them.

Thanks,

BPELEC.

 

[nbucska]

Use single ended [=SE] input -- balun --Device -- balun --
[SE] analyzer input.

Then take the transfer function [TF] of the baluns only:
[SE] input -- balun -- balun -- [SE] An. input

Then subtract the TF-s.

You may have to devide the frequency range into subranges
if the baluns can't cover it with acceptable loss.



Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[bpelec]

Thank you nbucska. Your method makes sense, and I will use it (assuming I can get hold of the baluns).

Best regards,

BPELEC.

 

[nbucska]

Good luck, just watch out for reflections !!!!

Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>