Characterize Noise Floor - Keysight x-series User Reference Manual

6 System Functions
System
Step 3 of the guided calibration sequence:

Characterize Noise Floor

On instruments with the NF2 license installed, the calibrated Noise Floor used by Noise Floor Extensions
should be refreshed periodically. To do this, press the Characterize Noise Floor key. When you press this
key, the instrument stops any measurement currently underway, and a dialog appears with an OK and
Cancel button which says:
"This action will take several minutes to perform. Please disconnect all cables from the RF input and press
Enter to proceed. Press ESC to cancel."
When you press Enter or OK, the characterization proceeds. After the characterization, the analyzer
restarts the measurement from the beginning (similar to pressing the Restart key). The characterization
takes many minutes to run.
The noise floor model used by NFE includes an estimation of the temperature behavior of the noise floor,
but this is only an estimation. The noise floor changes little with the age of the components. However, even
small changes in the estimated level of the noise floor can make large changes in the effective noise floor,
because the effective noise floor is the error in the estimation of the noise floor. Agilent recommends that
EMI Receiver Mode Reference 319