Concepts and features
R&S
®
ZNA
294User Manual 1178.6462.02 ─ 29
Noise power spectral densitiy
The noise power spectral density, or noise density for short, is calculated as
NPSD = ND = N
meas, corr
/ B
where N
meas, corr
denotes the measured sideband-corrected noise power, and B the
equivalent noise bandwidth (see "Receiver noise temperature" on page 291). N
meas, corr
is basically independent of what is currently connected to the test ports, so no distinc-
tion between calibration and DUT is required.
4.7.12 Measurement uncertainty analysis
Option R&S ZNA-K50/R&S ZNA-K50P
Measurement uncertainty analysis is available if option R&S ZNA-K50 and METAS
VNA Tools (version 2.2.6 or higher) are installed on the instrument.
Option R&S ZNA-K50P offers the same functionality as option R&S ZNA-K50, but
comes with METAS VNA Tools preinstalled. It can be shipped with new instruments or
installed at Rohde&Schwarz service.
The purpose of the METAS VNA Tools software is to compute uncertainties of S-
parameter measurements. After registration, you can download it from the VNA Tools
Internet site (https://www.metas.ch/vnatools).
●
The uncertainty analysis of the METAS VNA Tools is limited to S-parameter mea-
surements. Uncertainty analysis of wave quantities is not supported.
●
The uncertainty calculations are in line with EURAMET Calibration Guide No. 12
Version 3.0 (03/2018).
●
If external switch matrices are used, measurement uncertainty analysis is not sup-
ported.
METAS Calibration
The VNA firmware directly interacts with the DLLs of the METAS VNA Tools. During a
"METAS Calibration", the VNA firmware collects all data that are required to set up a
METAS VNA Tools project. After the "METAS Calibration"METAS calibration is comple-
ted, the analyzer is ready for real-time uncertainty analysis: after each sweep it passes
the raw (uncalibrated) S-parameters to the VNA tools and receives the calibrated S-
parameters plus uncertainties (95% confidence ellipse in the complex plane) in return.
The calibrated S-parameter traces plus their uncertainty bands can be displayed in
magnitude, phase, real and imaginary trace formats. The display of uncertainties in
complex diagrams (polar, Smith) is not supported.
Optional extensions and accessories
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