An unwanted voltage induced in a system by natural or man-made sources.
Note: In telecommunications systems, the disturbance voltage creates currents that limit or interfere with the interchange of information. An example of a disturbance voltage is a voltage that produces (a) false signals in a telephone, (b) noise in a radio receiver, or (c) distortion in a received signal.

1. Simulating a gray scale by using a group of pixels each capable of displaying only black and white.
2. A technique for varying raster color or intensity by illuminating and blanking pixels in patterns to produce a blurred transition from one color to another in a computer picture.
Note: Dithering is used to create a wide variety of patterns… (Read More →)

The phase shift of electromagnetic signals associated with daily changes in the ionosphere.
Note 1: The major changes usually occur during the period of time when sunrise or sunset is present at critical points along the path.
Note 2: Significant phase shifts may occur on paths wherein a reflection area of the path is subject to a large tidal range.… (Read More →)

See beam divergence.

The property of being made up of two or more different elements, media, or methods.
Note: In communications, diversity is usually used to provide robustness, reliability, or security.

A circuit or device for combining two or more signals carrying the same information received via separate paths or channels with the objective of providing a single resultant signal that is superior in quality to any of the contributing signals.

The ratio of the sum of the individual maximum demands of the various parts of a power distribution system to the maximum demand of the whole system.
Note: The diversity factor is always greater than unity.

In radio communications, the ratio of the signal field strength obtained by diversity combining to the signal strength obtained by a single path.
Note: Diversity gain is usually expressed in dB. [From Weik '89]

Radio reception in which a resultant signal is obtained by combining or selecting signals, from two or more independent sources, that have been modulated with identical information-bearing signals, but which may vary in their fading characteristics at any given instant.
Note 1: Diversity reception is used to minimize the effects of fading.
Note 2: The amount of received signal improvement… (Read More →)

Radio communication using a reception technique in which a resultant signal is obtained by combining signals (a) that originate from two or more independent sources that have been modulated with identical information-bearing signals and (b) that may vary in their transmission characteristics at any given instant.
Note 1: Diversity transmission and reception are used to obtain reliability and signal improvement… (Read More →)