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a unit used for expressing the ratio of two physical quantities of the same kind, the number of nepers being the natural logarithm of such a ratio. The neper is named after John Napier and abbreviated Np. The neper is defined as follows: 1 Np = In (F2 / F1) if F2 / F1 = e, where F2 and F1 are physical “force” quantities, for example, voltages, current strengths, and pressures, and e is the base of the natural system of logarithms. Nepers are used mainly for measuring attenuation (damping) of electric signals in communication lines. A neper is related to other logarithmic ratios by the following formulas: 1 Np = 2 log e bel ≈ 0.8686 bel = 8.686 decibels.