Concepts and features
R&S
®
ZND
173
User Manual 1173.9557.02 ─ 61
For a channel with more calibrated ports than cal unit ports available, you can change
the port assignments and rerun the automated validation. Or you can switch to
advanced mode and validate each port manually.
Advanced mode
In advanced mode you can configure the validation settings (reference characteriza-
tion, deviation limits) and run or rerun particular measurements (reflection at port p with
connected Open, Short or Match).
4.5.5.6
Multiple port assignments
With multiple port assignments, it is possible to calibrate several 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 reconnect the calibration unit between the different calibration stages
(assignments). It can 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
For Full n-Port calibrations, the R&S
ZND applies the "reduced through" logic to calcu-
late the correction terms for those test port pairs that are not covered by a single
assignment and hence cannot be measured directly (see
Chapter 4.5.1.11, "Full n-Port
calibration with reduced number of Through connections"
Calibration
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