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Concepts and features
R&S
®
ZND
137
User Manual 1173.9557.02 ─ 61
Timestamp
The timestamp comment line reflects the time at which the Touchstone file was cre-
ated. For "Version 1.1 (ZNx)" export format, it is represented as Coordinated Universal
Time (UTC):
! Created: UTC 12/24/2020, 5:20:26 PM
The other export formats "Version 1.1" and "Version 2.0" use local time (Greenwich
Mean Time + offset):
! Created: GMT+1 2020-12-24 18:20:26
Renormalization information
If, during export, the S-parameter data were renormalized with port-specific impedan-
ces, these impedances are written to the output file as a comment. In case the port-
specific impedances are different, a note points out that the impedance system under-
lying the data is not interpreted correctly during import:
! The following Port Impedance Renormalization has been used when saving the data.
! PortZ Port1:100+j0 Port2:50+j0
!
! Note: The Port Impedances differ from the reference impedance of this file.
! While reading the file the reference impedance value of the option line above
! is always used.
"Renormalization of S-parameters"
For the "Version 2.0" export format, the port impedances are currently not written to the
renormalization information comment. Instead, the real parts of the port impedances
appear as arguments of the
[Reference]
Network data table header
These comment lines indicate the content of the
below it.
As the first column of the data table is always designated to the frequency points, the
first table header comment always starts with
! freq[Hz]
.
●
"Version 1.1 (ZNx)" export format
For this format, the header explicitly specifies the exported parameters and their
data format. The port numbers of single-ended S-parameters in the header are the
"real" (physical) port numbers:
! freq[Hz] re:S22 im:S22 re:S12 im:S12 re:S21 im:S21 re:
S11 im:S11
Up to port reordering, which is possible via "snp free config" export and via logical
port assignment, the order in which the parameter data occur is the one described
in the Touchstone 1.1 standard. See
If balanced (and mixed mode) parameters are exported, the assigned logical port
numbers are used:
! freq[Hz] re:Sdd11 im:Sdd22 re:Scd22 im:Scd22 re:Sdc22 im:
Sdc22 re:Scc22 im:Scc22
Operations on traces
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