AMPLITUDEThe size of a signal as measured from a reference line to a maximum value above or below
the line. Generally used to describe voltage, current, or power  .
AMPLITUDE DISTORTIONDistortion that is present in an amplifier when the amplitude of the output
signal fails to follow exactly any increase or decrease in the amplitude of the input signal  .
AMPLITUDE MODULATIONAny method of varying the amplitude of an electromagnetic carrier
frequency in accordance with the intelligence to be transmitted .
AMPLITUDE STABILITYAmplitude stability refers to the ability of the oscillator to maintain a
constant amplitude in the output waveform .
AND CIRCUITSee AND GATE .
AND GATE(1) An electronic gate whose output is energized only when every input is in its prescribed
state. An AND gate performs the function of the logical "AND"; also called an AND circuit. (2) A
binary circuit, with two or more inputs and a single output, in which the output is a logic 1 only when
all inputs are a logic 1 and the output is a logic 0 when any one of the inputs is a logic 0 .
ANGLE MODULATIONModulation in which the angle of a sine-wave carrier is varied by a modulating
ANGLE OF INCIDENCEThe angle between the incident wave and the normal .
ANGLE OF INCLINATIONThe angular difference between the equatorial plane of the earth and the
plane of orbit of the satellite .
ANGLE OF REFLECTIONThe angle between the reflected wave and the normal .
ANGLE OF REFRACTIONThe angle between the normal and the path of a wave through the second
ANGSTROM UNITThe unit used to define the wavelength of light waves .
ANISOTROPICThe property of a radiator that allows it to emit strong radiation in one direction .
ANODE(1) A positive electrode of an electrochemical device (such as a primary or secondary electric
cell) toward which the negative ions are drawn  [6) . (2) The semiconductor-diode terminal that is
positive with respect to the other terminal when the diode is biased in the forward direction .
ANTENNAA conductor or set of conductors used to radiate RF energy into space or to collect RF energy
from space or to do both .
ANTENNA BEAM WIDTHWidth of a radar beam measured between half-power points .
ANTENNA COUPLERA device used for impedance matching between an antenna and a transmitter or
ANTENNA SYSTEMRoutes RF energy from the transmitter, radiates the energy into space, receives
echoes, and routes the echoes to the receiver .
ANTIJAMMING CIRCUITAn electronic circuit used to minimize the effects of enemy
countermeasures, thereby permitting radar echoes to be visible on the indicator .