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U1831C USB Noise Source - Technical Overview

Technical Overviews

U1831C USB Noise Source

10 MHz to 26.5 GHz

Noise Source Designed to Meet Specific Needs

The Keysight Technologies Inc U1831C USB noise source is designed to work with:

  • X-series signal analyzers 
  • NFA’B series of noise figure analyzers 
  • M9391/3A PXIe VSA

For noise figure measurement application covering both bench-top and modular solution.

The USB connectivity that comes with smart features of automatically download of electronically stored calibration data and temperature sensing. To simplify measurement set-up and improve accuracy this noise source automatically downloads electronically stored calibration data to the compatible Keysight noise figure measuring analyzers. The noise sources also have the capability to automatically measure their own temperature so that compensation can be applied to the calibration data. These capabilities increase the overall reliability and accuracy of noise figure measurements

U1831C key features and benefits

  • Automatic download of ENR data to the analyzers significantly speeds up the overall setup time 
  • Electronic storage of Excess Noise Ratio (ENR) calibration data decreases opportunity for user error 
  • Temperature sensing improves measurement accuracy, leading to tighter specification of device performance

The U1831C covers an operating frequency from 10 MHz to 26.5 GHz and comes with 3.5 mm (male) RF connector where it provides a DC drive through USB connectivity.

U1831C for accurate and reliable noise figure measurement of a device up to 26.5 GHz

The U1831C USB smart noise source was designed to measure DUT noise figures reliably and accurately up to 30 dB from 10 MHz up to 26.5 GHz. It serves as an ideal usage for general purpose use with low reflection coefficient and a nominal ENR value of 15 dB.

Accurate Noise Power

The output of a noise source, usually given in terms of Excess Noise Ratio (ENR), must be known in order to make accurate noise figure measurements. Any uncertainty in the ENR transfers into uncertainty of the measured noise figure, dB for dB. Keysight provides accurate ENR calibration data with each noise source. ENR uncertainty and reflection coefficients at each frequency point are provided as well. The following example is an example of calibration data for an U1831C USB smart noise source.


Specifications refer to the performance standards or limits against which the U1831C USB noise source is tested. These specifications for the noise are ONLY valid if the analyzers have been allowed to meet its specified warm up time of 60 minutes. Typical characteristics are included for additional information only and they are not warranted specifications. Those denoted as “typical”, “nominal” or “approximate” are printed in italic.


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