I would like to improve the dynamic range of my PNA N5242using front-panel jumpers, but in the PNA help, the method seems to correspond with transmission measurements. Is there any option for reflection measurements?
Another option that is suggested is alternate sweeps (although it has to be activated with commands instead of from user interface), but the result is reflection and transmission are measured on separate sweeps. If I only perform reflection measurements, that option does not change anything, is that right?
The configurable test set front panel jumpers allow you to bypass or reverse a port's coupler to increase dynamic range for transmission measurements.(e.g. S21).
Reflection measurements (e.g. S11) require a coupler by definition, hence the configurable test set offers no way to improve reflection dynamic range.
Refer to AN 1287-2: "Directivity is a measure of a coupler's ability to separate signals flowing in opposite directions along the through path of the coupler. It can be thought of as the dynamic range available for reflection measurements."
I presume you want to improve reflection dynamic range because you need to measure at a very low power (this is the typical reason for high-dynamic range S11 measurements). Reversing the port 1 coupler will lower the source power to your DUT by about 15 dB, and increase the sensitivity of the reflection by the same 15 dB. Thus you get lower power and keep the same S11 noise performance.
Why do you need higher dynamic range on reflection?
Alternative sweeps did improve crosstalk on only older instruments in some cases (mostly for transmission) such as HP8720 but since 15 years, there has been no need to do alternate sweeps. The commands are there for backward compatibility.
Thank you very much for your answer.
I need high dynamic range because I want to detect very small changes in my probe circuit (and so in S11) in the presence of a large background signal. (I already use a low IFBW and average)
Does reversing port 1 coupler work?
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