neper


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neper

[′nē·pər]
(physics)
Abbreviated Np. Also known as napier.
A unit used for expressing the ratio of two currents, voltages, or analogous quantities; the number of nepers is the natural logarithm of this ratio.
A unit used for expressing the ratio of two powers (even when this ratio is not the square of the corresponding current or voltage ratio); the number of nepers is the natural logarithm of the square root of this ratio; to avoid confusion, this usage should be accompanied by a specific statement.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Neper

 

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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

neper

The unit of measurement based on Napierian logarithms that represents the ratio between two values, such as current or voltage.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
References in periodicals archive ?
Between these two dark lunar "seas" is the complex 85-mile-wide crater Neper, which can be tough to identify.
The most obvious is the 137-km-wide Tycho-like crater, Neper. At full Moon an elongate central peak stands out as a bright ridge in a sea of gray.
where [[gamma].sub.jk] is lognormal random variable [15], and [mathematical expression not reproducible], where [delta].sub.jk] is a zero-mean Gaussian random variable in nepers. The mean and variance of [I.sub.s]/[P.sub.0] are given by:
It can be shown that the propagation constant is a complex quantity of the form [gamma] = [alpha] + i[beta], where the real part of the propagation constant is the attenuation constant [alpha] = R([gamma]) in nepers per meter and the imaginary part is the phase constant [beta] = T([gamma]) expressed in radians per meter.