R&S 1311.6010K22, Руководство пользователя

Страница: 168 / 1611

Concepts and features
R&S
®
ZNB/ZNBT
168 User Manual 1173.9163.02 ─ 62
total number of standard measurements for an n-port TOSM calibration is 3n + n (n-1)
= n (n+2) . However, this number can be significantly decreased without losing too
much precision (see Chapter 4.5.1.11, "Full n-Port calibration with reduced number of
Through connections" , on page 173)
The analyzer automatically performs each through measurement in both directions, so
the number of connected standards is smaller than the number of measurements.
Manual TOSM calibration supports Complementary isolation measurement (optional).
UOSM: TOSM with unknown Through
The analyzer can perform a TOSM calibration with any 2-port network serving as
through connection, as long as it fulfills the reciprocity condition S
21
= S
12
. The modified
TOSM calibration is referred to as UOSM (Unknown through – Open – Short – Match)
calibration. It can be selected as follows:
●
If different connector types are assigned to the test ports, the analyzer automati-
cally replaces TOSM by UOSM.
[The network analyzer supports different connector types at its test ports to mea-
sure DUTs with different port connectors; see also
Chapter 4.5.1.5, "Adapter
removal" , on page 168. ]
●
If the same connector types are used but an appropriate Through standard is not
defined, the analyzer also replaces TOSM by UOSM.
●
UOSM can be selected explicitly in the "Calibration Setting" dialog.
After acquiring the calibration sweep data for the unknown through, the analyzer auto-
matically determines its delay time/transmission phase.
4.5.1.5 Adapter removal
Many DUTs use different connector types on their RF ports (e.g. port 1: N-type connec-
tor, female; port 2: PC 3.5-type connector, female).
DUTs of this sort are also known as noninsertable devices .
A suitable calibration kit is then required for each of the different connector types. The
kit must include, as a minimum, the standards that are used for one-port calibration.
The through-connection between test ports with different connector types must be
made using
adapters .
The problem here is that unlike Through standards, adapters are usually not character-
ized, i.e. their delay time/transmission phase is unknown.
If the adapter fulfills the reciprocity condition S
21
= S
12
, it can serve as U nknown
through in an U OSM calibration (see "UOSM: TOSM with unknown Through"
on page 168).
Calibration