Keysight Technologies N9040B UXA Manual page 29

Making Noise Figure Measurements
Making Frequency Converter Measurements
A system downconverter is part of the measurement system, and is present in
both the calibration setup and the measurement setup. See
calibration the noise performance of both the analyzer and the system
downconverter are measured. Because of this, when corrected measurements
are performed, the results then apply to the DUT only. If there are no more
frequency conversions in the DUT, ENR data for the same frequency range is
used for both calibration and measurements.
The analyzer can be used in much more complex systems, with multiple
frequency conversions between the DUT and the noise source. However, the
control of such systems is application-specific. You need to perform frequency
calculations to suit that particular system, account for the effects of any DSB
conversions, determine filter requirements, and calculate the appropriate ENR
values for calibration and the measurement.
To connect the analyzer and make your measurements:
Step
1. Turn the analyzer on.
MODE/MEAS
2. Press
Mode Preset
to return the analyzer to a
known state.
3. Enter the ENR values into the analyzer if
required.
4. Refer to "Setting up External LO Control"
on page 77 to set up the LO control for the
system downconverter and DUT as
required.
MEAS SETUP
5. Press
Calibration
, and set the DUT Setup form
as required.
MEAS SETUP
6. Press
Averaging
toggle
7. Configure the measurement connection to
calibration setup as shown in
MEAS SETUP
and press
perform calibration.
8. Change the measurement connections to
the measurement setup as shown in
2-6
and make the corrected
measurements.
N9069C Noise Figure Measurement Guide
Noise Figure OK,
, ,
DUT Setup &
,
Avg/Hold Num 10
, , ,
On
to .
Figure 2-6
CALIBRATE
, to
Figure
Notes
"Entering Excess Noise Ratio (ENR) Data" on
See
page 64
for the procedures to do this.
Note that you need to use an external LO control to control
another signal generator as the LO if the LO Freq Mode for
either DUT or the system downconverter is set to Swept.
"DUT Setup Form" on page 61
Refer to
detailed information for each parameters in the DUT setup
form.
Setting averaging here reduces jitter and provides more
accurate measurement results.
"Setting Averaging" on page 74
See
Figure 2-6. During
to see the
for more details.
29