18WuD2x

14 adapter • address generation
auxiliary system or unit used to extend the operation
of another system (e.g., a citizens-band
adapter for a broadcast receiver).
adaptive communication A method of communication
that adjusts itself according to the particular
requirements of a given time.
adaptive suspension vehicle Abbreviation, ASV.
A specialized robot that moves on mechanical
legs, rather than on wheels. It generally has six
legs and resembles an insect. It is designed to
move over extremely irregular or rocky terrain,
and to carry a human passenger.
adaptivity The ability of a system to respond to its
environment by changing its performance characteristics.
adc Abbreviation of ANALOG-TO-DIGITAL CON-
VERTER.
Adcock antenna A directional antenna system
consisting of two vertical antennas, spaced in
such a way that the whole array behaves like a
loop antenna. Its members are connected and positioned
so that it discriminates against horizontally
polarized waves, and delivers output that is
proportional to the vector difference of signal voltages
induced in the two vertical arms.
Adcock direction finder A radio direction-finding
system based on the directivity of the ADCOCK
ANTENNA.
Adcock radio range A radio range system with
four ADCOCK ANTENNAS situated at the corners
of a square, and a fifth antenna at the center of
the square.
add-and-subtract relay A stepping relay that can
be switched either uprange (add) or downrange
(subtract).
addend In a calculation, any number to be added
to another. Compare AUGEND.
addend register In a digital computer, the register
that stores the addend.
adder 1. In a digital computer, the device or circuit
that performs binary addition. A HALF ADDER is
a two-input circuit that can produce a sum output
and a carry output, but it cannot accommodate
a carry signal from another adder. A FULL
ADDER can accommodate a carry input, as well
as two binary signals to be added. Also see ANA-
LOG ADDER. 2. A circuit in a color TV receiver
that amplifies the receiver primary matrix signal.
additive 1. The character or characters added to a
code to encipher it. 2. In a calculation, an item
that is to be added. 3. An ingredient, usually in a
small quantity, added to another material to improve
the latter in quality or performance.
additive color A color formed by combining the
rays from two or three primary-colored lights
onto a single neutral surface. For example, by
projecting a red and a green beam onto a neutral
screen, a yellow additive color results.
additive primaries Primary colors that form other
colors in a mixing of light (see ADDITIVE COLOR),
but are not themselves formed by mixing other
additive primaries. For example, red, green, and
blue are the additive primaries used in color television.
Through appropriate mixing, these colors
can be used to generate an unlimited variety of
other colors. Compare SUBTRACTIVE PRI-
MARIES, which form the color spectrum by mixing
pigments rather than lights. In additive
systems, each superimposed primary color increases
the total light output from the reflecting
(viewing) surface; in subtractive systems, each superimposed
primary decreases the total reflectivity.
Thus, equal combination of additive primaries
produces gray or white, and equal combination of
subtractive primaries produces gray or black.
addition record An extra data store created in a
computer during processing.
address 1. In computer operations, a usually numerical
expression designating the location of
material within the memory or the destination of
such material. 2. The accurately stated location
of information within a computer; a data point
within a grid, matrix, or table; a station within a
network. 3. In computer operations, to select the
location of stored information.
address comparator A device that ensures that
the address being read is correct.
address computation In digital computer operations,
the technique of producing or modifying
only the address part of an instruction.
address field In a computer, the part of the instruction
that gives the address of a bit of data (or
a word) in the memory.
address generation The programmed generation
of numbers or symbols used to retrieve records
from a randomly stored direct-access file.