Recovery of “true amplitudes” from distributions of scanned amplitudes. (A) Histograms f(a_s) of scanned amplitudes for a set of sparks consisting in three groups with equal numbers, simulated using three values of current (5, 20, and 50 pA) at three durations (5, 10, and 20 ms). Three alternative binning intervals were used, as indicated. The distribution of true amplitudes in the simulation consists therefore of three Dirac deltas (see below). (B) Distributions g(a) of true amplitudes, derived from f(a_s) in A using Eq. A1. Dashed lines mark the position of true (in-focus) amplitudes of simulated sparks, 0.634, 2.27, and 3.66. Narrow binning is best at locating low amplitude modes and vice versa.