[The] Portion of a trusted computing base whose normal function is to control access between subjects and objects and whose correct operation is essential to the protection of data in the system. [INFOSEC-99]

The artificially generated time history of an earthquake, derived from the histories of many actual earthquake accelerometers. The reference waveform is to be used for test performance. [T1.329-1995]
Note: The reference waveform is useful in CIP (communications infrastructure protection) efforts.

[In television,] The level corresponding to the specified maximum excursion of the luminance signal in the white direction. [47CFR]

The ratio of reflected power to incident power, generally expressed in dB or percent.

Synonym Gray code.

In the ionosphere, a layer that has a free-electron density sufficient to reflect radio waves.
Note 1: The principal reflecting layers are the E, F1, and F2 layers in the daylight hemisphere.
Note 2: A critical frequency is associated with the reflection by each layer.

See reflection loss.

The abrupt change in direction of a wave front at an interface between two dissimilar media so that the wave front returns into the medium from which it originated.
Note 1: Reflection may be specular (i.e., mirror-like) or diffuse (i.e., not retaining the image, only the energy) according to the nature of the interface.
Note 2: Depending on the nature… (Read More →)

1. The ratio of the amplitude of the reflected wave and the amplitude of the incident wave.
2. At a discontinuity in a transmission line, the complex ratio of the electric field strength of the reflected wave to that of the incident wave.
Note 1: The reflection coefficient may also be established using other field or circuit quantities.
Note 2:… (Read More →)

1. At a discontinuity or impedance mismatch, e.g., in a transmission line, the ratio of the incident power to the reflected power.
Note 1: Reflection loss is usually expressed in dB.
Note 2: The reflection loss, Lr, is given by where Z1 and Z2 are the respective impedances, and the vertical bars designate absolute magnitude.
2. In an optical fiber,… (Read More →)