NFM has been updated to v1.18.0.
It includes for user convenience, a noise measurement uncertainty calculator based on the discussion of uncertainty of the noise sampling process at (Duffy 2007b) and the calculator at (Duffy 2007c)
Above is a screen shot of the popup accessed from the Options menu (registered users only).
The fast option uses an inverse square law extrapolation from the value for 1000 samples (2*bandwidth*interval). It is automatically selected from long calculations, automatically deselected for very small sample sizes. It is a compute intensive calculation, and may take some time.
- Duffy, O. 2007. noise figure meter software (NFM). https://owenduffy.net/software/nfm/index.htm (accessed 01/04/2014).
- ———. 2007b. Uncertainty of the noise sampling process. https://www.owenduffy.net/files/NoiseMeasurementUncertainty.pdf .
- ———. 2007c. Noise measurement uncertainty calculator. VK1OD.net (offline).