Keysight N9927-90001 User’s Guide 579
Noise Figure Mode (Option 356 – CPU2 Only)
How to Define a Noise Figure Measurement
— Noise Source Reflection Coefficient, ENR Uncertainties, and ENR values:
For this section, see also “Overview of Softkey Menus” on page 555 (Noise
Source on page 556) and “Using ENR Tables” on page 581.
Noise source reflection coefficients, ENR Uncertainties, and ENR values
may be entered by Recalling a previously generated *.enr file, editing an
ENR table, or set as a spot value to be applied across all frequencies. Note
that any *.enr file which uses the standard *.enr file format may be recalled
by the Noise Figure mode.
As in the case of the DUT, in addition to entering the magnitude reflection
coefficient values, the uncertainty calculation takes into account the
distribution and specified style for the noise source reflection coefficient
value. Additionally, the ENR table requires a value for the ENR uncertainty
coverage (Uncert Coverage), which states how the entered ENR uncertainty
(ENR Uncert) value is related to the population of possible ENR
uncertainties. This is typically set to 2
σ which means that 95% of the time,
the actual ENR is within the range of ENR +/- ENR Uncertainty.
— Preamplifier Reflection Coefficients (User Calibration Only):
For this section, see also “Overview of Softkey Menus” on page 555
(Uncertainty
> Preamp on page 561).
When a user calibration is performed, the Preamplifier Reflection
Coefficient values may be imported to a Preamp table from *.snp or *.csv
files, entered by editing a preamplifier table (Preamp Table), recalled as a
previously saved preamp table (in a *.amp file), or set as a spot value to be
applied across all frequencies.
Template *.enr files for several common models of noise sources may be
found in the default ENR table directory of the FieldFox. In these files, the
reflection coefficients have been set to the values specified for the
respective model numbers, but the values for the ENR or ENR uncertainty
will need to be entered at each frequency. Refer to “ENR (*.enr) Files” on
page 582.
Template preamplifier (*.amp) files for several common models of
preamplifiers may be found in the default
Preamp table directory of the
FieldFox. In these files, the reflection coefficients have been set to the
values specified for the respective model numbers.
DUT and preamplifier *.snp files may be generated in the FieldFox VNA
mode, and then imported into the Noise Figure mode.
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