18WuD2x

420 loss • lower sideband suppressed carrier
loss Energy that is dissipated without doing useful
work in a circuit or system. See POWER LOSS.
loss angle For an insulating material, 90 degrees
minus the PHASE ANGLE.
loss index For an insulating material, the product
of the POWER FACTOR and the DIELECTRIC
CONSTANT.
lossless data compression A process in which
the number of bits in a data file is reduced by
eliminating redundancies, without sacrificing
any of the precision or detail in the file. Compression
of text and programs must usually be
lossless. Image compression need not generally
be lossless. Compare LOSSY DATA COMPRES-
SION.
lossless line A perfect transmission line (i.e., one
having no resistance loss, no dielectric loss, and
no radiation loss). It is not realizable in practice,
but useful in some theoretical calculations.
loss tangent See DISSIPATION FACTOR, 1.
lossy data compression A process in which the
number of bits in a data file (especially a digital
image) is reduced by eliminating redundancies,
with some sacrifice of precision or detail. In image
compression, some loss can usually be tolerated,
allowing larger compression ratios than would be
possible if zero loss were mandatory. Lossy compression
is not generally acceptable for text files
and programs. Compare LOSSLESS DATA COM-
PRESSION.
lossy line A line or cable having comparatively
high or excessive attenuation per unit length.
loudness The amplitude of sound, especially in audio
reproduction equipment, such as a highfidelity
stereo amplifier. Also called VOLUME.
loudness control See COMPENSATED VOLUME
CONTROL.
loudness curves See AUDIBILITY CURVES.
loudness switch/button In a high-fidelity audio
amplifier, a switch or button that can be actuated
when music is played at low loudness. Increases
the volume of the bass relative to the midrange
and treble.
loudspeaker A transducer that converts electrical
impulses into sound waves of sufficient volume to
be heard easily by a number of listeners situated
at some distance from the device. Also called
speaker.
loudspeaker damping See DAMPED LOUD-
SPEAKER.
loudspeaker dividing network See CROSSOVER
NETWORK.
low 1. The logical digit 0. 2. Of relatively small
magnitude (e.g., LOW VOLTAGE and LOW-
FREQUENCY). 3. In a rechargeable cell or battery,
the condition of being near the end of the discharge
cycle.
low band 1. The low or lowest frequency band
used in communications, testing, or processing
in a given situation. 2. Television channels 2 to
6 (54 to 88 MHz). 3. In two-way radio operations,
those radio channels between 30 MHz
and about 70 MHz.
low battery 1. The condition of a battery needing
replacement or recharging. 2. An indicating device
that shows when a battery needs to be replaced
or recharged.
low-battery bias current The current into a designated
pin of an integrated circuit required for
proper operation of the LOW-BATTERY INDICA-
TOR.
low-battery indicator A device, such as a lightemitting
diode (LED) and associated circuitry,
that gives a visible indication of the condition of
LOW BATTERY.
low-capacitance probe A test probe in which capacitance
has been minimized to reduce loading
and detuning of the circuit under test.
low earth orbit Acronym, LEO. An artificial satellite
orbit that is comparatively low in altitude, resulting
in a short orbital period (in some cases less than 2
hours). See also LEO SATELLITE SYSTEM.
low-energy criterion See VON HIPPEL BREAK-
DOWN THEORY.
lower sideband Abbreviation, LSB. In an amplitude-modulated
wave, the lower band of frequencies
equal to the difference between the carrier
frequency and the modulating frequency. Compare
UPPER SIDEBAND.
lower sideband suppressed carrier Abbreviation,
LSSC. A single-sideband transmission technique
in which the lower sideband is transmitted,
but the upper sideband and carrier are suppressed.
Compare DOUBLE SIDEBAND SUP-
PRESSED CARRIER and UPPER SIDEBAND
SUPPRESSED CARRIER.