18WuD2x

416 local station • logarithmic voltmeter
local station A station situated within the same
general area as the receiver, as opposed to a distant
station.
local system library A computer program library
containing standard software associated with a
specific system.
local transmission The sending of signals to receivers
in the same general locality as the transmitter,
as opposed to long-distance transmission.
local trunk In a telephone system, the interconnecting
line between local and long-distance
lines.
location In digital computer operation, a memory
position (often a register) specified by an address
and usually described in terms of the basic storage
unit a particular system uses (e.g., a character
is a location in a character-oriented machine).
location counter A register in the control section
of a computer containing the address of the instruction
being executed.
locked groove A continuous blank groove around
the inside of a phonograph record. When the disc
is done playing, this groove keeps the stylus from
running into the label or sliding across the disc.
locked oscillator 1. A fixed-frequency oscillator,
such as a crystal-controlled oscillator. 2. See
BRADLEY DETECTOR.
lock-in A state of synchronism, as when a selfexcited
oscillator is synchronized (locked-in) with
a standard-frequency generator.
lock-in amplifier A detector that makes use of a
balanced amplifier. The output is the difference
between the collector or drain currents of the two
devices.
locking circuit See HOLDING CIRCUIT.
locking relay See LATCHING RELAY.
lock-in relay See LATCHING RELAY.
lock-out 1. To prevent a hardware unit or routine
from being activated (e.g., when there would be a
conflict between operations using the same areas
of memory). 2. A safeguard against an attempt to
refer to a routine in use.
lock-up relay An electromagnetic relay that can be
locked in the actuated state nonmechanically
(i.e., by means of an electromagnet or permanent
magnet).
locus The set of all points located by stated conditions
(e.g., the locus of secondary points that are
all equidistant from a primary point is a sphere).
lodestone A natural magnet; a form of the mineral
magnetite. Also spelled loadstone.
log 1. Abbreviation of LOGARITHM. 2. A continuous
record of communications kept by a station,
or a record of the operation of an equipment.
log 10 Abbreviation of common logarithm (base-10
logarithm). Also called Briggsian logarithm.
logarithm Abbreviation, log. The power y to which
a fixed number a, called the base, must be raised
to equal a given number x. Suppose x = a y , where
a, x, and y are real numbers. Then, log a x = y. The
most common logarithmic bases are 10 and the
transcendental number e, approximately equal
to 2.71828. See COMMON LOGARITHM and
NAPIERIAN LOGARITHM.
logarithmic amplifier An amplifier whose outputsignal
amplitude is proportional to the logarithm
of the input-signal amplitude.
logarithmic curve A graphical representation of a
logarithmic function, having the form y = k log a x,
where k is a nonzero real-number constant, and
a is a positive real number (the logarithmic base).
logarithmic decrement See DECREMENT.
logarithmic graph Also called log-log graph. A
graph in which the x and y axes are both incremented
logarithmically. Compare SEMILOG-
ARITHMIC GRAPH.
logarithmic horn A horn whose diameter varies
directly, according to the logarithm of the displacement
along the axis. See HORN.
logarithmic mean See GEOMETRIC MEAN.
logarithmic meter A current meter or voltmeter
whose deflection is proportional to the logarithm
of the quantity under measurement. The increments
on the scale of such an instrument are
closer together in the upper portion.
logarithmic rate of decay See EXPONENTIAL DE-
CREASE.
logarithmic rate of growth See EXPONENTIAL
INCREASE.
logarithmic response 1. Response in which the
value of a dependent variable is at every point
proportional to the logarithm of the independent
variable. 2. A type of response in which a quantity
(such as current) varies directly with the logarithm
of another quantity (such as voltage).
logarithmic scale A graduated scale in which the
coordinates are positioned, according to the logarithm
of the actual distance from the origin.
logarithmic voltmeter See LOGARITHMIC
METER.
Linear
0
1
2
Logarithmic
1
2
3
4
6
10
20
30
40
60
100
logarithmic scale