A loss of optical power that occurs at a splice or a pair of mated connectors when the numerical aperture of the "transmitting" fiber exceeds that of the "receiving" fiber, even if the cores are precisely the same diameter and are perfectly aligned. [FAA]
Note 1: The higher numerical aperture of the transmitting fiber means that it emits a larger… (Read More →)

Abbreviation for near-vertical-incidence skywave.

1. In the North American direct distance dialing numbering plan, a central office code of three digits that designates a particular central office or a given 10,000-line unit of subscriber lines; "N" is any number from 2 to 9, and "X" is any number from 0 to
9.
2. The three digits (in positions 4, 5, and 6) in an… (Read More →)

The maximum time interval between equally spaced samples of a signal that will enable the signal waveform to be completely determined.
Note 1: The Nyquist interval is equal to the reciprocal of twice the highest frequency component of the sampled signal.
Note 2: In practice, when analog signals are sampled for the purpose of digital transmission or other processing, the… (Read More →)

The reciprocal of the Nyquist interval, i.e., the minimum theoretical sampling rate that fully describes a given signal, i.e., enables its faithful reconstruction from the samples.
Note: The actual sampling rate required to reconstruct the original signal will be somewhat higher than the Nyquist rate, because of quantization errors introduced by the sampling process.

A theorem, developed by H. Nyquist, which states that an analog signal waveform may be uniquely reconstructed, without error, from samples taken at equal time intervals. The sampling rate must be equal to, or greater than, twice the highest frequency component in the analog signal. Synonym sampling theorem.

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