R&S ZNB Series User Manual page 159

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R&S ZNB/ZNBT
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
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
Otherwise it sets it to 50 (Ω).
●
Port-specific
In this case, the reference impedances of the individual ports are used for the
renormalization and these impedances are documented in the
information
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
User Manual 1173.9163.02 ─ 62
Reference impedances
comment. If the port-specific reference impedances are different, an
Concepts and features
Option line is taken as common target
Option line to the real part of this impedance.
Operations on traces
Renormalization
159