24 Noise

In the communications sense, noise is best described as a phenomenon that destroys information. In the electronic sense, it represents signals of any form that are unwanted, including signals from random variations of electrical charge from all sources, interference from signals that are required by other users and even distortion to the wanted signal. The presence of such noise is therefore often the limiting factor in signal detection and this gives rise to the term signal to noise power ratio (S/N ratio) which defines a system sensitivity to noise. Noise and interference are different in nature. Noise appears as randomly varying voltages that are not related in either phase or frequency. By comparison, interference tends to be periodic ...

Get Communications Technology Handbook, 2nd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.