Hi,

I am using N5230C PNA with the Time Domain option to evaluate an impedance profile of my DUT. I base my procedure on the Agilent note detailed here:

http://www.home.agilent.com/agilent/faq ... id=1294511

Initially, I had problems getting my starting point to start at exactly 100 Ohms (after applying the Equation Editor to normalize to 100 Ohms). I found out that using Gating fixes this problem â€“ my reference line now starts at very close to 100 Ohms.

However, I am still no clear on whether I should start my Transform at some â€“ve point as in the Agilent document above (where the Transform start is at -400ps) or start at 0. What is the Agilent recommendation for the proper Transform procedure ?

Thanks !

I am using N5230C PNA with the Time Domain option to evaluate an impedance profile of my DUT. I base my procedure on the Agilent note detailed here:

http://www.home.agilent.com/agilent/faq ... id=1294511

Initially, I had problems getting my starting point to start at exactly 100 Ohms (after applying the Equation Editor to normalize to 100 Ohms). I found out that using Gating fixes this problem â€“ my reference line now starts at very close to 100 Ohms.

However, I am still no clear on whether I should start my Transform at some â€“ve point as in the Agilent document above (where the Transform start is at -400ps) or start at 0. What is the Agilent recommendation for the proper Transform procedure ?

Thanks !

The real question to be answered is why is it not 100 ohms at 0 seconds? I think it may be because your line is not actually 100 ohms at the calibration reference plane. There may be other subtle reasons, but I think that is the most likely. Second most likely is probably the calibration itself.

I have been comparing my PNA impedance profiles with what I get using the PLTS. When I do time domain analysis of my DUT with PLTS, my reference starts at very close to 100 Ohms. This is why I was expecting to get the same result using the PNA.