FAST-TIME-CONSTANT CIRCUITDifferentiator circuit in the first video amplifier that allows
only the leading edges of target returns, no matter how small or large, to be used.
FEEDBACKThe return of a portion of the output of a circuit to its input.
FEEDHORNA horn radiator used to feed a reflector.
FIRST DETECTORSee Mixer.
FREQUENCY COMPENSATION NETWORKCircuit modification used to improve or broaden the
linearity of its frequency response.
FREQUENCY SCANNINGVarying the output frequency to achieve electronic scanning.
FREQUENCY SPECTRUMIn a radar, the entire range of frequencies contained in an rf pulse or
FREQUENCY SYNTHESIZERA bank of oscillators in which the outputs can be mixed in various
combinations to produce a wide range of frequencies.
GAINAny increase in the strength of a signal.
GATED AGCCircuit that permits automatic gain control to function only during short time intervals.
GLOW DISCHARGEDischarge of electricity through a gas in an electron tube.
GROUND CLUTTERUnwanted echoes from surrounding land masses that appear on a radar
GROUND RANGEThe distance on the surface of the earth between a radar and its target. Equal to
slant range only if both radar and target are at the same altitude.
GROUND-CONTROLLED APPROACHRadar system used to guide aircraft to safe landings in
poor visibility conditions.
GUIDANCE RADARSystem which provides information that is used to guide a missile to a target.
HALF-POWER POINTA point on a waveform or radar beam that corresponds to half the power of
the maximum power point.
HARD-TUBE MODULATORA high-vacuum electron tube modulator that uses a driver for pulse
HEIGHT-FINDING RADARRadar that provides target altitude, range, and bearing data.
HITS PER SCANThe number of times an rf beam strikes a target per antenna revolution.
HORIZONTAL PLANEImaginary plane that is tangent (or parallel) to the earth's surface at a given
HORN ANTENNASee Horn Radiator.
HORN RADIATORA tubular or rectangular microwave antenna that is tapered and is widest at the