Noise that has a frequency spectrum of predominately zero power level over all frequencies except for a few narrow bands or spikes.
Note: An example of black noise in a facsimile transmission system is the spectrum that might be obtained when scanning a black area in which there are a few random white spots. Thus, in the time domain, a… (Read More →)

1. In facsimile systems using amplitude modulation, recording in which the maximum received power corresponds to the maximum density of the record medium.
2. In a facsimile system using frequency modulation, recording in which the lowest received frequency corresponds to the maximum density of the record medium.

In facsimile, the signal resulting from scanning a maximum-density area of the object.

A signal that represents only unclassified or encrypted information, usually in cryptographic systems.

See cipher-text.

A totally absorbing body that does not reflect radiation.
Note: In thermal equilibrium, a blackbody absorbs and radiates at the same rate; the radiation will just equal absorption when thermal equilibrium is maintained.

The interference that is caused by the presence of an AM broadcast signal of one volt per meter (V/m) or greater strengths in the area adjacent to the antenna of the transmitting station. The 1 V/m contour is referred to as the blanket contour and the area within this contour is referred to as the "blanket area. " [47CFR]

In the vicinity of a transmitting antenna, the area in which the signal from that antenna interferes with the reception of other signals.
Note: The blanketing area around a given transmitting antenna depends on the selectivity and sensitivity of the receiver, and on the respective levels of the other signals in question.

1. The period of time in which no video image is displayed. [JP 1-02]
2. In graphic display, the suppression of the display of one or more display elements or display segments.

In raster-scanned television technology, the period between (a) the end of one horizontal scanning line and the beginning of the next (the horizontal blanking interval), or (b) the end of one field and the beginning of the next (the vertical blanking interval), during which the display of picture information is suppressed.
Note 1: Blanking intervals were a necessary part of… (Read More →)