deletions | additions       diff --git a/Background estimation.tex b/Background estimation.tex  index e74f792..f0b1767 100644  --- a/Background estimation.tex  +++ b/Background estimation.tex 
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\verb|d.calc_bg(bg.exp_fit, time_s=30, tail_min_us=2000)|  Here, the first argument is the actual fitting function used to fit the background in each period and for each photon stream. The function \verb|bg.exp_fit| fits the background using a Maximum Likelihood Estimation (MLE) of the delays distribution. More fitting functions are avaliable in \verb|bg| namespace (see the \href{http://fretbursts.readthedocs.org/en/latest/background.html}{\verb|background| module}). The second argument, time_s, \verb|time_s|,  is the background period and the third argument is the threshold above which the distribution is supposed to be exponential. It is possible to use a different threshold for each photon stream passing a tuple as tail_min_us (instead that a scalar). For an ALEX measurement the tuple needs to have 5 values corresponting to thresholds for the 5 photon streams. The list of photon streams for a \verb|Data| object can be found in the \verb|ph_streams| attribute (in the present example \verb|d.ph_streams|). Finally, is possible to use an heuristic estimation of the threshold using \verb|tail_min_us='auto'|. For more details refer to the \href{http://fretbursts.readthedocs.org/en/latest/data_class.html#fretbursts.burstlib.Data.calc_bg}{\verb|calc_bg| documentation}. \verb|d.calc_bg(bg.exp_fit, time_s=1000, tail_min_us='auto', F_bg=1.7)|