58 N9069C Noise Figure Measurement Guide
Measurement Related Tasks and Concepts
Setting the Measurement System
Calibrating the Analyzer
To compensate for the noise contribution of the analyzer and associated
cabling in the measurement path, a calibration is necessary. The calibration
measures the analyzer’s noise contribution with no device under test (DUT) in
place. This correction is often referred to as the second stage calibration. The
correction is then applied to the measurement with the DUT in place.
To perform a calibration you need to enter the ENR values and set up the
frequency range, number of measurement points, the bandwidth, the
averaging, and measurement mode to be used during the measurement.
Corrected Measurements
You can make corrected measurements only at frequencies that are covered by
the current calibration. Attempting to make corrected measurements at
frequencies less than the lowest calibration frequency or greater than the
highest calibration frequency will generate an error and invalidate the
calibration.
To proceed you must either:
— perform a calibration over the desired measurement frequency range
— change the measurement frequency to one covered by the existing
calibration
— perform uncalibrated measurements
Uncorrected measurements actually measure the noise figure of the
analyzer and any associated components in the input path. This can be
useful if you wish to use the Uncertainty Calculator.
If you alter the frequency range after you have calibrated the analyzer, it
changes the analyzer’s status to either the uncalibrated (a red
UNCAL
indicator) or the interpolated (
a yellow ~ENR
indicator) calibrated state.
Before you can make another measurement to the specified accuracy, you
must either recalibrate the analyzer, or recall a previously saved state file
in which the calibration data has been saved.
If you perform a measurement outside the calibrated range of the analyzer,
Apply Calibration
is automatically set to
Off
and a message is displayed
stating
User Cal:Cal invalidated
. If you then change your
measurement frequency back to a frequency within the calibrated range,
the previous error message will be replaced by a message stating
User
Cal:Cal valid
. Apply Cal from MEAS SETUP menu. Press
MEAS SETUP
,
Cal Setup
tab,
Apply Calibration
to
On
to make a corrected measurement.
Summary of Contents for CXA N9000B
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