Concepts and features
R&S
®
ZNB/ZNBT
159
User Manual 1173.9163.02 ─ 62
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
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
to the real part of this impedance.
Otherwise it sets it to 50 (Ω).
●
In this case, the reference impedances of the individual ports are used for the
renormalization and these impedances are documented in the
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
ZNB/ZNBT itself), the
<reference resistance>
of the Touchstone option
line is used and the impedance system underlying the data is not interpreted cor-
rectly.
4.4.2.2
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;
...
The header consists of the following data elements:
●
<Stimulus> stimulus variable: freq for Frequency sweep, power for Power sweep,
time for Time sweep, trigger for CW Mode sweep.
●
<reTrace1> first response value of first trace: re<Trace_Name>,
mag<Trace_Name> or db<Trace_Name> for output format Re/Im, lin. Mag-Phase
or dB Mag-Phase, respectively. The data format for export files can be selected in
the Export Data dialog.
●
<imTrace1> second response value of first trace: im<Trace_Name> for output for-
mat Re/Im, ang<Trace_Name> for output formats lin. Mag-Phase or dB Mag-
Phase. The data format for export files can be selected in the Export Data dialog.
●
<reTrace2> first response value of second trace: re<Trace_Name>,
mag<Trace_Name> or db<Trace_Name> for output format Re/Im, lin. Mag-Phase
Operations on traces