Concepts and Features
R&S
®
ZNB/ZNBT
143
User Manual 1173.9163.02 ─ 38
quency-dependent attenuation and phase shift in the measurement path (reflection or
transmission tracking error). It does not compensate for directivity or mismatch errors.
This limits the accuracy of a normalization.
Manual transmission normalizations support
Complementary Isolation Measurement
(optional).
4.5.1.2
Reflection OSM Calibration
A reflection OSM (full one-port) calibration requires a Short, an Open and a Match
standard to be connected to a single test port. The three standard measurements are
used to derive all three reflection error terms:
●
The Short and Open standards are used to derive the source match and the reflec-
tion tracking error terms.
●
The Match standard is used to derive the directivity error.
A reflection OSM calibration is more accurate than a normalization but is only applica-
ble for reflection measurements.
4.5.1.3
One Path Two Ports Calibration
A one path two ports calibration combines a reflection OSM (full one-port) calibration
with a transmission normalization. The fully calibrated port is termed the node port.
This calibration type requires a Short, an Open and a Match standard to be connected
to a single test port plus a Through standard between this calibrated source port and
the other load ports. The four standard measurements are used to derive the following
error terms:
●
The Short and Open standards are used to derive the source match and the reflec-
tion tracking error terms at the source port.
●
The Match standard is used to derive the directivity error at the source port.
●
The Through standard provides the transmission tracking error terms.
For calibration of two ports, a one-path two-port calibration requires only four standards
to be connected (instead of 7 for a full two-port TOSM calibration). It is suitable when
only the forward (e.g. S
11
and S
21
) or reverse S-parameters (e.g. S
22
and S
12
) are nee-
ded, and if the DUT is well matched, especially at the load port. It is also the best cali-
bration method for test setups with unidirectional signal flow, e.g. a pulsed measure-
ment using an external generator.
4.5.1.4
TOSM and UOSM Calibration
TOSM
A TOSM (Through – Open – Short – Match) calibration requires the same standards as
the one path two ports calibration, however, all measurements are performed in the
forward and reverse direction. TOSM is also referred to as SOLT (Short – Open – Load
Calibration
