3
Specifications
24
Keysight N4000/1/2A Operating and Service Manual
The uncertainty for each noise source can be unique to that noise source. The
uncertainty will typically vary by less than 0.01 dB at any frequency between
different noise sources produced in the same year when first produced.
Subsequent calibrations must be performed at suitably capable calibration
vendors in order to keep the uncertainties similar.
The standard level of calibration for the SNS series is Option A1R (calibration
against a 1-level removed reference standard). Another choice is Option APR
(calibration against a primary reference standard).
For Option A1R, performance can only be matched with a Standards Lab
Calibration, available from the Roseville Standards Lab at Keysight. For Option
APR, performance can only be matched by the National Physical Laboratory (NPL)
in the UK.
Using the appropriate calibration level should result in similar uncertainties to the
original production uncertainties. These will mostly be within 0.01 dB of the
original uncertainties, but they will vary with each calibration because they
include the repeatability observed on each device. Uncertainties for newly
produced devices include population repeatabilities instead of individual device
repeatabilities, and thus vary little between devices of the same model and option
configuration.
and
show example uncertainties for standard (Option A1R)
production noise sources, as of the end of 2013. This time period is after
significant changes were made in the uncertainties from better understanding of
the error sources and improvements in the references from the National Metrology
Institute used, NPL. If NPL performance changes in the future, Keysight
uncertainties will follow those changes.
