Keysight Technologies N9040B UXA Manual page 43

Making Noise Figure Measurements
Using the U7227-Series USB Preamplifiers in Noise Figure Measurements
Below is the procedure for using
system configuration. See
System Configuration" on page 46
1. Check the DUT and get the rough data for the DUT band width (BW), noise
2. Calculate the bandwidth adjust factor (AF) using the following equation.
3. Use the DUT_NF and DUT_Gain_Modified values to search in
4. Find the corresponding system configuration. If the system configuration
As in the calculation of the supported DUT characteristics in
Figure 2-17
try the system configuration below the one you find using DUT_NF and
DUT_Gain_Modified first.
N9069C Noise Figure Measurement Guide
figure (NF), and gain.
AF = 10 × log ( Ref_BW DUT_BW
Then subtract the AF from the DUT Gain. The resultant value is called
DUT_Gain_Modified.
DUT_Gain_Modified
or Figure 2-17 from bottom to top and find an approximate place for them.
includes the internal attenuation, do the following to find the proper
attenuation level:
a. Set the attenuation to 0 dB and note the noise figure of your DUT.
b. Increase the attenuation by one step (4 dB). If the noise figure
changes too much, such as 0.3 dB, this attenuation is required for
accurate measurement.
c. Repeat step (b) until you find the proper value.
, the most precise data is used in most cases, it is recommended to
1. The Ref BW is the bandwidth used in
noise power, which is 3.59 GHz.
Figure 2-16 and
"Examples for Using the Guide to Find the Test
for examples of using this procedure.
⁄ ) = 10 log ( 3.59
×
= DUT_Gain AF
-
Figure 2-16
Figure 2-17 to find the proper
9
1
× 10 ⁄ DUT_BW )
Figure 2-16
Figure 2-16
and
Figure 2-17
or to calculate the
43