, and especially in physics
is random fluctuations and the addition of external factors to the stream of target information (signal
) being received at a detector.
More specifically, in physics, the term noise has the following meanings:
1. An undesired disturbance within the frequency band of interest; the summation of unwanted or disturbing energy introduced into a communications system from man-made and natural sources.
2. A disturbance that affects a signal and that may distort the information carried by the signal.
3. Random variations of one or more characteristics of any entity such as voltage, current, or data.
4. A random signal of known statistical properties of amplitude, distribution, and spectral density.
5. Loosely, any disturbance tending to interfere with the normal operation of a device or system.
Some sections copied from Federal Standard 1037C and from MIL-STD-188