Nepertelecommunication, a neper (Np) is a unit used to express ratios, such as gain, loss, and relative values. The name is derived from John Napier, the inventor of logarithms.
Like the bel it is a logarithmic measure; the difference being that where the bel uses base-10 logarithms to compute ratios, the neper uses base e (2.71828182846...). 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, that is, logarithm to the base e.
- 1 neper (Np) = 8.686 dB, where 8.686 = 20/(ln 10).