Contents - Index

Noise Figure (NF)
The Noise Figure (NF) is a measure of the signal-to-noise degradation by a component under test.  It is expressed in dB.
The Noise Figure is a two channel measurement similar to a Transfer Function where the input is compared with the output.  In the case of the Noise Figure, it is the difference between the SNR at the output and the SNR at the input of the device.  An ideal device has a Noise Figure of 0 dB; practical devices always have a larger Noise Figure than this.
A sinusoidal input test signal such as a 1kHz tone should be used as the source.  The Noise Figure can be setup as either "Left vs Right" or "Right vs Left".  If the input signal is on the right channel and the output on the left, you should use "Left vs Right" otherwise the Noise Figure will be negative.
This utility will only be available when the analyzer is setup for dual channel operation (stereo) under the <Options><Settings> dialog box.
This utility window can be resized as required by the user and its contents will update anytime a new spectrum is computed.  

  • Hanning or Blackman smoothing window is recommended because of its low noise quality.  
  • An FFT size of 2048 or greater is recommended in order to to provide adequate spectral resolution.
  • The contents of any open utility window will be printed on the right margin of the spectrum view.

    See Also: SNR, SINAD