Hi all,

good day to you. Hopefully there is someone able to help me on the enquiry:

On the E5071B/E5071C ( i assume the specs are the same as PNA), for the tranmission and reflection uncertainty specs, i find out they have put S11=S22=0 for tranmission uncertainty, and S21=S12 =0 for reflection uncertainty.

After downloading the VNA uncertainty calculator , then at the "Set Chart Parameter" , i find out the setting for S11 and S22 for tranmission (S21) is 0 too, and S21 and S12 is 0 for Reflection (S11),

i wonder is there any reason we have 0 for respective S11 and S22 measurement? and also, in the uncertainy calculator, if i change the to 0.5 or 1 maximum, what will be the impact on the unit?

and finally, did the uncertainty calculator provide me the uncertainty specs after connecting the DUT with network analyzer, or before connecting the DUT?

thanks if anyone can provide the clarification.

Have a nice day.

good day to you. Hopefully there is someone able to help me on the enquiry:

On the E5071B/E5071C ( i assume the specs are the same as PNA), for the tranmission and reflection uncertainty specs, i find out they have put S11=S22=0 for tranmission uncertainty, and S21=S12 =0 for reflection uncertainty.

After downloading the VNA uncertainty calculator , then at the "Set Chart Parameter" , i find out the setting for S11 and S22 for tranmission (S21) is 0 too, and S21 and S12 is 0 for Reflection (S11),

i wonder is there any reason we have 0 for respective S11 and S22 measurement? and also, in the uncertainy calculator, if i change the to 0.5 or 1 maximum, what will be the impact on the unit?

and finally, did the uncertainty calculator provide me the uncertainty specs after connecting the DUT with network analyzer, or before connecting the DUT?

thanks if anyone can provide the clarification.

Have a nice day.

In the uncertainty calculator, I believe you can set the values for S11, S22, when computing S21.

In general, the S21 uncertainty is equal to cal uncertainty + measurment uncertainty.

for low loss devices, this works out to 2*(RawSM*corLM+RawLM*CorSM). For cases where S11 or S22 is large, it becomes

RawSM*corLM+S11*CorSM+S22+CorLM+S21*S12(RawSM*CorrLM+RAwLM*corSM).

Where RawSm,LM is raw sourcematch and a load match, and corrSM,LM is Corrected (or residual) sourcematch or load match. For case where S11 and S22 are big, S12 and S21 are typically small.