neper noun1 •A non-SI unit of the attenuation (or sometimes gain) of field and power quantities such as electronic signals; the natural logarithm of a ratio, with 1 Np (a ratio of 2.718:1) being equivalent to 8.686 dB.Values of b, the amplitude attenuation constant, are given for various materials in Table 1.1. Having dimensions of [length]⁻¹, it is usually measured in nepers per centimetre (Np cm⁻¹). — 1994 formsnepers
