Page 66 - The Illustrated Dictionary of Electronics

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automatic interrupt • automatic secure voice communications 51

automatic phase control In a color television (TV)
receiver, a circuit that synchronizes the burst sig-
nal with the 3.58-MHz color oscillator.
automatic pilot An electronic device, often com-
puter-controlled, that automatically keeps a ship,
airplane, or space vehicle on course.
automatic polarity In an electronic metering de-
vice, a means of automatically switching the in-
put polarity of the instrument when the input
signal polarity is shifted. Also called bipolar oper-
ation.
automatic programming See AUTOMATIC COD-
ING.
automatic protective device A circuit or device
(such as a fuse, circuit breaker, limiter, or regu-
lator) that protects another circuit or device by
automatically removing, reducing, or increasing
the current or voltage during overload or under-
load.
automatic radio compass See AUTOMATIC
DIRECTION FINDER.
automatic ranging In a metering device, the auto-
matic adjustment or optimization of the full-scale
range to compensate for large changes in the in-
put parameter.
automatic regulation 1. Voltage regulation. In a
power supply, the automatic holding of the output
voltage to a constant value, despite variations in
the input voltage or load resistance. 2. Current reg-
ulation. In a power supply, the automatic holding
of the output current to a constant value, despite
variations in the input voltage or load resistance.
automatic interrupt A program interruption automatic relay The relaying of messages auto-
caused by hardware or software acting in re- matically from one station to another via interme-
sponse to some event independent of the pro- diate points, without the need for human
gram. operators.
automatic level compensation See AUTOMATIC automatic repeater station A station that re-
GAIN CONTROL. ceives signals and simultaneously retransmits
automatic level control Abbreviation, ALC. 1. A them, usually on a different frequency.
circuit that adjusts the input gain of a magnetic- automatic reset 1. The self-actuated restoration
tape recording device to compensate for changes of a circuit or device to a given state (e.g., the
in the loudness of the sound reaching the micro- state of rest). 2. A circuit or device that restores
phone. 2. A form of AUTOMATIC GAIN CONTROL another circuit or device to a given state.
used in single-sideband (SSB) radio transmitters automatic scanning 1. The automatic (usually
to maintain linearity while increasing the level of repetitive) tuning or adjustment of a circuit or
the average power relative to the peak power. system throughout a given frequency range. In a
automatic line feed In the digital transmission of radio receiver, the system can be programmed to
printed matter, the automatic insertion of a line pause or stop at occupied channels, passing over
feed (LF) character immediately following every vacant ones; or it can be programmed to pause or
carriage return (CR) character. stop at vacant channels, passing over occupied
automatic modulation control Abbreviation, ones. 2. The repetitive sweep of a cathode-ray-
AMC. In a frequency-modulated (FM) radio trans- tube (CRT) electron beam.
mitter, a form of AUTOMATIC GAIN CONTROL automatic scanning receiver Also called
that regulates the gain of the audio amplifiers to PANORAMIC RECEIVER. A radio receiver that is
compensate for fluctuating audio input ampli- automatically tuned (usually repetitively) over a
tude. This prevents overdeviation while optimiz- frequency band. Such a receiver either homes in
ing signal intelligibility. on a signal when one is found, or displays on a
automatic noise limiter Abbreviation, ANL. Any cathode-ray-tube (CRT) screen the distribution of
of several circuits for clipping noise peaks ex- signals in the band.
ceeding a predetermined maximum received- automatic secure voice communications A wide-
signal amplitude. band and narrowband voice-digitizing application