In satellite communications system operations, a fixed communication channel access plan, as opposed to a demand assignment access plan in which allocation of accesses or the number of channels per access is varied in accordance with the demand. [From Weik '89]

In communications, a designation assigned to a message by the originator to indicate to communications personnel the relative order of handling and to the addressee the order in which the message is to be noted. [After JP1]
Note: The descending order of precedence for military messages is FLASH, IMMEDIATE, PRIORITY, and ROUTINE.

The loss of energy by an electromagnetic wave because of scattering, refraction, and/or absorption during its passage through a volume of the atmosphere containing precipitation such as rain, snow, hail, or sleet.

Radio interference caused by the impact of charged particles against an antenna.
Note: Precipitation static may occur in a receiver during certain weather conditions, such as snowstorms, hailstorms, rainstorms, dust storms, or combinations thereof.

A frequency that is maintained to the known accuracy of an accepted reference frequency standard.
Note: Current uncertainty among international standards is approximately 1 part in 1014 as of 1995.

A time mark that is accurately known with respect to an accepted reference time standard.
Note: Current uncertainty among international standards is approximately 1 part in 1014 as of 1995.

The discipline that addresses precise timekeeping and time information transfer.

1. The degree of mutual agreement among a series of individual measurements, values, or results; often, but not necessarily, expressed by the standard deviation.
2. With respect to a set of independent devices of the same design, the ability of these devices to produce the same value or result, given the same input conditions and operating in the same environment.… (Read More →)

Optical fiber splicing that uses a capillary tube, of suitable material, to align the mating fibers.
Note: The capillary tube has an inside diameter slightly larger than the cladding diameter of the two optical fibers to be spliced. The fibers are inserted, one from either end, to form a butt joint. The capillary tube may contain an index-matching gel, or… (Read More →)

The combining of multiplexed signals prior to the modulation of the carrier. [From Weik '89] Synonym premodulation combining.