The weighting can be exponential or linear.

•Exponential Averaging                is comparable to a low-pass time filtering of the spectrum. In other words each spectral line is low-pass filtered so that the resulting spectrum is smoothed out over time. In that case the Nb_Avg represents an equivalent averaging time constant, expressed in number of successive spectra. The averaging is continuous and does not stop. Each successive spectrum is taken into account in the calculation. A larger value of Nb_Avg produces a spectrum that is more stable, but also averages-out short-lived transients.
•Linear Averaging                takes an equal-weight average of Nb_Avg successive spectra. After the Nb_Avg­ spectra have been observed the result is frozen.

In both cases the Reset button discards the present display and restarts the averaging from zero.