Concepts and Features
R&S
®
ZNB/ZNBT
165
User Manual 1173.9163.02 ─ 38
For Full n-Port calibrations, the R&S
ZNB/ZNBT applies the "reduced through" logic to
calculate 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"
on the calibration type, a "minimal" valid and complete solution can be described as
follows:
Calibration
type
Minimal solution
Default solution (minimal)
Full One Port
Each calibrated test port must appear in exactly one
port assignment.
Subdivide the n test ports into
groups of m ports with increasing
port numbers. Create a separate
port assignment for each group.
One Path Two
Port
●
The node port must be included in all port
assignments
●
Each of the n-1 other calibrated test ports must
appear in exactly one port assignment
Additional condition:
The calibration unit port
assigned to the node port must be the same in all
assignments. This minimizes the number of port re-
connections between the calibration stages.
Assign the node port to port 1 of
the calibration unit. Subdivide the
remaining n–1 test ports into
groups of m–1 ports. Create a
separate port assignment for each
group; leave port 1 of the calibra-
tion unit connected to the node
port and connect the ports of each
of the port groups to the remain-
ing m–1 ports of the calibration
unit.
Full n-Port
●
the two generic conditions stated above (with
"unordered Throughs")
●
the number of assignments must be as small
as possible
Additional condition:
The cal unit port assigned to a
given test port must be the same in all assignments.
Again, this minimizes the number of port re-connec-
tions between the calibration stages.
Same as for One Path Two Port
calibrations, using the test port
with the lowest number as "node
port".
(Every other calibrated port could
serve as "node port")
Among the minimal ones, the "star-shaped" solutions with fixed (but arbitrary) "node
port" are also optimal w.r.t. the (average) length of the "Chain of Throughs" and hence
the accuracy of the calculated Throughs. Additional port assignments may improve the
accuracy, provided that they add more measured through connections.
For full n-port calibrations, an extra assignment is required if
●
an External Switch Matrix is used
●
3 or more test ports shall be calibrated, all of them located on the
same submatrix
●
only 2 Cal Unit ports are available
Starting with the minimal solution (as explained above), create an additional 2-port
assignment for a pair of ports that was previously not covered by a single, but by two
assignments.
See
Chapter 4.7.20, "External Switch Matrices"
on page 226 for background informa-
tion on switch matrices and their submatrices.
Calibration
