AI-1
APPENDIX I
GLOSSARY
A-SCOPE—A radar display on which slant range is shown as the distance along a horizontal trace.
ACQUISITION—Operational phase of a fire- control or track radar during which the radar system
searches a small volume of space in a prearranged pattern.
AIR-CONTROL PANEL—Panel that monitors the dry-air input at each user equipment.
ALTITUDE—Vertical distance of an aircraft or object above a given reference, such as ground or sea
level.
AMBIGUOUS RETURNS—Echoes that exceed the prt of a radar and appear at incorrect ranges.
AMPLITRON—See Crossed-Field Amplifier.
ANTENNA BEAM WIDTH—Width of a radar beam measured between half-power points
ANTENNA SYSTEM—Routes rf energy from the transmitter, radiates the energy into space, receives
echoes, and routes the echoes to the receiver.
ANTIJAMMING CIRCUIT—Electronic circuit used to minimize the effects of enemy
countermeasures, thereby permitting radar echoes to be visible on the indicator.
ANTITRANSMIT-RECEIVE TUBE (atr)—Tube that isolates the transmitter from the antenna and
receiver. Used in conjunction with tr tube.
ARTIFICIAL TRANSMISSION LINE—An LC network that is designed to simulate characteristics of
a transmission line.
ASYMMETRICAL MULTIVIBRATOR—Multivibrator that generates rectangular waves.
AUTOMATIC GAIN CONTROL—Circuit used to vary radar receiver gain for best reception of signals
that have widely varying amplitudes.
AVERAGE POWER—Output power of a transmitter as measured from the start of one pulse to the start
of the next pulse.
AZIMUTH—Angular measurement in the horizontal plane in a clockwise direction.
BALANCED MIXER—Waveguide arrangement that resembles a T and uses crystals for coupling the
output to a balanced transformer.
BEAM—See Lobe.
BEARING RESOLUTION—Ability of a radar to distinguish between targets that are close together in
bearing.
BEAT FREQUENCIES—Difference and sum frequencies which result from combining two different
frequencies.
