Concepts and features
R&S
®
ZNA
292User Manual 1178.6462.02 ─ 29
For the receiver NF calibration, a well matched 50 Ω load connected to the receiving
port and the noise power is measured. The model used for the receiver noise calibra-
tion is shown in Figure 4-30 and depicts the matched load (at ambient temperature)
directly connected to the receiver.
Figure 4-30: Model used for the receiver noise calibration
Using the model above, it is possible to calculate the receiver noise temperature T
rec
using the following formula:
In this formula, N
M,rec
is the measured noise power during calibration, k is the Boltz-
mann constant (1.38064852e‑23 J/K), and B is the equivalent noise bandwidth of the
used IF filter.
The equivalent noise bandwidth represents the cumulated normalized filter response.
In other words, it is the bandwidth of a rectangular filter which has the same integrated
noise power as the real filter. The calculation is done by the following equation:
where H(jω) is the magnitude of the IF filter, H
max
is the maximum value of H(jω).
DUT noise figure
Amplifier (non-frequency-converting DUTs)
The calculation of the noise figure (NF) of a non-frequency-converting DUT requires a
calibrated NF channel in the R&S ZNA setup. During calibration, important system
parameters such as Source noise temperature and Receiver noise temperature are
determined. The final noise factor F
D
is then calculated using the following equation:
where
●
N
DUT,meas
is the noise power measured with the DUT connected to the VNA
●
T
rec
and T
source
are the source and receiver noise temperature, respectively, deter-
mined during calibration
Optional extensions and accessories
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