VNA Concepts and Features
R&S
®
ZNL/ZNLE
239
User Manual 1178.5966.02 ─ 07
S
11
can be replaced by an any S-parameter, so the
*.s1p
format is suitable for export-
ing an arbitrary data trace representing an S-parameter.
2-port files (*.s2p)
! freq[Hz] re:S11 im:S11 re:S21 im:S21 re:S12 im:S12 re:S22 im:S22
(all values arranged in 1 line)
The stimulus frequencies are arranged in ascending order. If a "Lin. Mag-Phase" (MA)
or "dB Mag-Phase" (DB) data format is selected, the real and imaginary S-parameter
values
re:Sij im:Sij
are replaced by
mag:Sij ang:Sij
or
db:Sij ang:Sij
, respectively.
The entries in the data lines are separated by white space, and a data line is termina-
ted by a new line character.
Conditions for Touchstone file export
●
One-port Touchstone files with data from a single trace
Touchstone files are normally intended for a complete set of <n>-port S-parame-
ters. The only exceptions are one-port Touchstone files that can be created using
an arbitrary trace. This type of export can be accessed using either the GUI func-
tion [Trace ] > "Trace Data" > "s1p Active Trace..." or the remote command
MMEMory:STORe:TRACe
.
The following restrictions apply to this export type:
–
the reference resistance of the Touchstone option line is fixed to 50 Ω - regard-
less of the reference impedance setting of the involved port
–
the data file type of the Touchstone option line is fixed to S (for S-parameter)
although the trace can represent a different parameter type
●
Touchstone files containing S-parameters
–
For a one-port Touchstone file, the reflection coefficient for the specified port
(S
ii
for port i) must be measured. If a full one-port (Refl OSM) or a full n-port
(TOSM, ...) calibration is available for the specified port, it is possible to export
the data even when the trace is not displayed.
–
For a multiport Touchstone file
*.s<n>p
, either a full multiport system error
correction or a complete set of n
2
S-parameters must be available. If the port
configuration contains balanced ports, the exported Touchstone file contains
the converted single-ended S-parameters.
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] > "Trace Data" softtool or by the
remote command
MMEMory:STORe:TRACe:PORTs
.
Renormalization of S-parameters
Renormalization means that the S-parameters at connector impedances are converted
into S-parameters at certain target impedances. During export the S-parameters can
be renormalized in two ways: either a common target impedance is used for all ports or
the individual port reference impedances are used.
Operations on Traces
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