neper (Np)
1. A unit used to express ratios, such as gain, loss, and relative values.
Note 1: The neper is analogous to the decibel, except that the Naperian base
2. 71828182
8. . . is used in computing the ratio in nepers.
Note 2: The value in nepers, Np, is given by Np = ln(x1/x2), where x1 and x2 are the values of interest, and ln is the natural logarithm, i.e., logarithm to the base e.
Note 3: One neper (Np) =
8. 686 dB, where
8. 686 = 20/(ln 10).
Note 4: The neper is often used to express voltage and current ratios, whereas the decibel is usually used to express power ratios.
Note 5: Like the dB, the Np is a dimensionless unit.
Note 6: The ITU recognizes both units.