Keysight Technologies CXA N9000B, Manual

Page: 35 / 88

N9069C Noise Figure Measurement Guide 35
Making Noise Figure Measurements
Calculating Measurement Uncertainty
The following procedure takes the measurement results on the amplifier in
“Making Basic Measurements” on page 14 section as an example, to calculate
the measurement uncertainty.
Step Notes
1. Press
MEAS SETUP
,
Uncertainty
Calculator
.
Perform this step after the corrected measurement results are
obtained.
2. On the Measurement Uncertainty
Calculator dialog, toggle the
Automate settings from DUT Setup
and measurement results setting
to On.
This will automatically fill the parameters required for the
measurement uncertainty calculation from the instrument and
measurement results.
Once the setting is set to On,
— the noise source type is set to
Auto (SNS)
if an SNS
is connected.
— the instrument type is set to
Auto
.
— the Ext Preamp type is set to
Auto
if an U7227-Series
USB Preamplifier is connected.
Then the parameters for these devices will be loaded from the
instrument automatically.
You can also change these types to
Manual
and enter the
corresponding parameters manually.
3. If you are using a Keysight SNS noise
type, go to step 4 directly.
If you are using a Keysight 346x series
noise source, choose the model
number you are using from the
NS:
drop-down list.
For other noise sources, choose
Manual
in the
Noise Source
type list
and enter
NS ENR Uncert (dB)
and
NS Match
values manually.
4. Enter the
DUT In Match
and
DUT Out
Match
values and choose the spec
style and distribution.
The values for DUT match can be either read from the data sheet or
measured. They can be entered as return loss (-XX.X dB), VSWR, or
reflection coefficient.
It is recommended that the spec style is set to Fixed.
5. Click the
Update at current CF
button to show the measurement
uncertainty for the current
measurement results. The following
figure shows the uncertainty calculator
screen.
If you need to calculate measurement uncertainty for other
frequency points, enter the frequency value in the box near the
Update at selected frequency
button, and click the
Update at selected frequency
button to display the
results for that frequency.