R&S ZNL Series - Page 244

VNA concepts and features
R&S
®
ZNL/ZNLE
244User Manual 1178.5966.02 ─ 20
– For a multiport Touchstone file *.s<n>p, either a full multiport system error
correction or a complete set of n
2
S-parameter traces must be available.
If the port configuration contains balanced ports, the exported Touchstone file
contains the converted single-ended S-parameters unless you enable "Bal-
anced Params" during export.
– Export of balanced (symmetric) S-parameters must be enabled. If you want to
export balanced S-parameters, make sure that all these parameters are mea-
sured, and that for each involved balanced port both physical ports are part of
the export.
This type of export can be initiated from the GUI by using the "s<n>p Port ..." or
"snp Free Config. ..." functions of the Trace Data tab or by the remote command
MMEMory:STORe:TRACe:PORTs on page 871.
Renormalization of S-parameters
Renormalization means that the S-parameters at connector impedances are converted
to S-parameters at certain target impedances.
During Touchstone export, the S-parameters can be renormalized in two ways:
●
Common target impedance
The <reference resistance> of the Option line is taken as common target
impedance and the data is renormalized to the common target impedance, regard-
less of the reference impedances of the involved ports.
If the impedances of all involved ports are identical, the analyzer sets the
<reference resistance> in the Option line to the real part of this impedance.
Otherwise it sets it to 50 (Ω).
●
Port-specific Reference impedances
In this case, the reference impedances of the individual ports are used for the
renormalization and these impedances are documented in the Renormalization
information comment. If the port-specific reference impedances are different, an
additional warning is added to this comment, indicating that the option line contains
a non-matching reference resistance.
Note that when reimporting this type of file into standard applications (including the
R&S ZNL/ZNLE itself), the <reference resistance> of the Touchstone option
line is used and the impedance system underlying the data is not interpreted cor-
rectly.
9.4.2.2 ASCII (*.csv) files
An ASCII file contains a header and the actual trace data:
freq;reTrc1_S21;imTrc1_S21;reMem2[Trc1]_S21;imMem2[Trc1]_S21;
300000.000000;0.000000;0.000000;0.000000;0.000000;
40499497.487437;0.000000;0.000000;0.000000;0.000000;
80698994.974874;0.494927;-0.065174;0.500833;-0.074866;
120898492.462312;0.497959;-0.111724;0.488029;-0.107375;
...
Operations on traces