Concepts and features
R&S
®
ZNA
263
User Manual 1178.6462.02 ─ 20
present in the receiver. An additional step is required during calibration to characterize
the noise of the receiver.
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
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
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
Optional extensions and accessories
