Concepts and Features
R&S
®
ZNB/ZNBT
164
User Manual 1173.9163.02 ─ 38
2. Connect the calibration unit to the network analyzer.
3. Access the "Characterize Cal Unit" dialog (CHANNEL – CAL > "Cal Devices" >
"Characterize Cal Unit...") and select "Start Characterization...".
4. Step through the "Characterization" wizard, following the instructions in the dialogs.
Dependency between calibration types and characterization data
A cal unit characterization provides full one-port (OSM) data at the selected ports plus
two-port (Through) data between any pair of selected ports. The measurement of
Through data is optional, however, it is required for some calibration types. The follow-
ing table gives an overview.
Calibration type
Characterization data required
Refl Norm Open
Refl Norm Short
Refl OSM
UOSM
TOSM
OSM CalPort 1, OSM CalPort2 ... (all calibrated
ports)
Trans Norm Both
Trans Norm Forward
One Path Two Ports
OSM CalPort 1, OSM CalPort2 ... (all calibrated
ports), Through (between all pairs of ports)
4.5.5.4
Multiple Port Assignments
With multiple port assignments, it is possible to calibrate a number of test ports that
exceeds the number of ports of the calibration unit or cal unit characterization in use.
E.g. you can use a 2-port calibration unit to perform a full 4-port calibration.
The multiple port assignment method considerably extends the range of applications of
the calibration units. However, the method entails some loss of convenience because
you have to re-connect the calibration unit between the different calibration stages
(assignments). It may also cause a loss of accuracy because only a subset of all possi-
ble through connections is measured.
To calibrate n test ports with an m-port calibration unit (m<n), the calibration unit has to
be reconnected at least n/m times. Each of these (re-)connections is described by its
"port assignment", i.e. the mapping of calibration unit ports to test ports. Then for each
assignment an automatic calibration is performed. Finally the analyzer combines the
calibration data and calculates the required n-port error terms.
This is possible if and only if
●
the port assignments "cover" the calibrated test ports
●
the overlap between assignments allows a(n ordered) "chain of measured through
connections" between any (ordered) pair of test ports requiring a Through mea-
surement
Calibration
