attenuation

communications The progressive reduction in amplitude of a

signal as it travels farther from the point of origin.

For example, an electric signal's amplitude reduces with

distance due to electrical impedance. Attenuation is

usually measured in decibels [per metre?].

Attenuation does not imply appreciable modification of the

shape of the waveform (distortion), though as the signal

amplitude falls the signal-to-noise ratio will also fall

unless the channel itself is noise free or the signal is

amplified at some intermediate point(s) along the channel.

["Networking Essentials, second edition",

Microsoft Corporation, pub. Microsoft Press 1997].

(2003-07-29)