neper

plural nepers

1. businessA 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.

   The attenuation constant for the phantom muscle tissue is αₘ = 10.0 nepers/m.

   2008, Alan J. Fenn, Adaptive Phased Array Thermotherapy for Cancer, page 105

   2 more examples

   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, T. G. Leighton, The Acoustic Bubble, page 28

   The unit of α is nepers per meter. It can be easily seen that if a line has an attenuation constant of 1 neper/m, a unit amplitude voltage wave will reduce to e⁻¹ over a distance of 1 meter.

   2006, R. K. Shevgaonkar, Electromagnetic Waves, page 15