Page 30 - The Illustrated Dictionary of Electronics

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address indirect • adjusted decibels 15

address indirect An address that specifies a stor-
age location that contains another address.
address memory The memory sections in a digital
computer that contain each individual register.
address modification In computer operations,
altering only the address portion of an instruc-
tion; if the command or instruction routine is
then repeated, the computer will go to the new
address.
address part In a digital computer instruction, the
part of an expression that specifies the location.
Also called ADDRESS FIELD.
address register In a computer, a register in which
an address is stored.
add/subtract time In a computer, the time re-
quired to perform addition or subtraction, ex-
cluding the time required to get the quantities
from storage and to enter the sum or difference
into storage. from the picture signal in the next higher chan-
add time In computer operations, the time re- nel and the sound signal in the next lower
quired to perform addition, excluding the time re- channel.
quired to get the quantities from storage and to adjacent-channel selectivity The extent to which
enter the sum into storage. a receiver or tuned circuit can receive on one
a/d converter A device that changes an analog channel and reject signals from the nearest outly-
quantity into a digital signal. See ANALOG-TO- ing channels.
DIGITAL CONVERSION. adjacent sound channel In television, the radio-
ADF Abbreviation of AUTOMATIC DIRECTION frequency (RF) channel containing the sound
FINDER. modulation of the next lower channel.
ADI Abbreviation of ALTERNATE DIGIT INVER- adjacent video carrier In television, the radio-
SION. frequency (RF) carrier containing the picture
adiabatic damping In an accelerator (see ACCEL- modulation of the next higher channel.
ERATOR, 1), reduction of beam size as beam en- adjustable component Any circuit component
ergy is increased. whose main electrical value can be varied at will
adiabatic demagnetization A technique using a (e.g., a variable capacitor, inductor, resistor, or
magnetic field to keep a substance at a low tem- load).
perature, sometimes within a fraction of a degree adjustable instrument 1. An instrument whose
of absolute zero. sensitivity, range, or response can be varied at
adjacency A character-recognition condition in will (e.g., multirange meter or wideband genera-
which the spacing reference lines of two charac- tor). 2. An instrument that requires adjustment
ters printed consecutively in line are closer than or manipulation to measure a quantity (e.g.,
specified. bridge, potentiometer, or attenuator).
adjacent- and alternate-channel selectivity The adjustable motor tuning An arrangement that al-
selectivity of a receiver or radio-frequency (RF) lows the motor tuning of a receiver to be confined
amplifier, with respect to adjacent-channel and to a portion of the frequency spectrum.
alternate-channel signals. That is, the extent to adjustable resistor A wirewound resistor in which
which a desired signal is passed, and nearby un- the resistance wire is partially exposed to allow
wanted signals are rejected. varying the component’s value.
adjacent audio channel See ADJACENT SOUND adjustable voltage divider A wirewound resistor
CHANNEL. with terminals that slide on exposed resistance
adjacent channel The channel (frequency band) wire to produce various voltage values.
immediately above or below the channel of in- adjusted circuit A circuit in which leads that are
terest. normally connected to a circuit breaker are
adjacent-channel attenuation The reciprocal of shunted so that current can be measured under
the selectivity ratio of a radio receiver. The selec- short-circuit conditions without breaker trip-
tivity ratio is the ratio of the sensitivity of a re- ping.
ceiver (tuned to a given channel) to its sensitivity adjusted decibels Noise level (in decibels) above a
in an adjacent channel or on a specified number reference noise level (designated arbitrarily as
of channels removed from the original. zero decibels) measured at any point in a system
adjacent-channel interference In television or with a noise meter that has previously been ad-
radio reception, the interference from stations justed for zero (at reference), according to specifi-
on adjacent channels. A common form arises cations.