"A",
"B",
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"
"A" to "Ang", "Anh" to Ant", "Ap" to Az"
ABSOLUTE ALTITUDE: The altitude of an object relative to the ground beneath it.
ACCEPTABLE DEGRADATION: The allowable reduction in system performance. For a fire control radar, the acceptable degradation is usually expressed as a reduction in range; for example, the maximum lock-on range might be degraded by 25 percent without loss of essential defense capability.
ACQUISITION: The process between the initial location of a target and the final alignment of the tracking radar on the target. Operational phase of a fire-control or track radar during which the radar system searches a small volume of space in a pre-arranged pattern. A procedure by which a fire control tracking radar attains initial lock-on. Usually, the approximate target coordinates are supplied to the tracking radar and it searches a predetermined volume of space to locate the target.
AEROSOLS: Solid particles dispersed in the atmosphere having resonant size particles with a high index of refraction. The particles both scatter and absorb visual and laser directed energy so as to cut down on weapon systems directed by these techniques.
AFC (AUTOMATIC FREQUENCY CONTROL): An arrangement whereby the frequency of an oscillator or the
tuning of a circuit is automatically maintained within specified limits with respect to a reference frequency. A magnetron drifts in frequency over a period of time. The AFC of a radar makes the local oscillator shift by an equal amount so the IF frequency will remain constant.
AGC (AUTOMATIC GAIN CONTROL): A method for automatically obtaining an essentially constant receiver
output amplitude. The amplitude of the received signal in the range gate determines the AGC bias (a DC voltage) which controls the receiver gain so as to maintain a nearly constant output even though the amplitude of the input signal changes.
AIR-CONTROL PANEL: Panel that monitors the dry-air input at each user equipment. [Environmental Alarm Manufacturers].
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.
AMPLIFIER: An electronic device used to increase signal magnitude or power. See also GaAs FET Amplifier, Klystron Amplifier, Traveling-Wave Tube Amplifier. [RF Equipment Amplifier Manufacturers].
Transistor RF Amplifier
AMPLITUDE MODULATION (AM): A method of impressing a message upon a carrier signal by causing the carrier amplitude to vary proportionally to the message waveform.
AMPLITUDE SHIFT KEYING (ASK): A method of impressing a digital signal upon a carrier signal by causing the carrier amplitude to take different values corresponding to the different values of the digital signal.
ANGLE JAMMING: ECM technique, when azimuth and elevation information from a scanning fire control radar is jammed by transmitting a jamming pulse similar to the radar pulse, but with modulation information out of phase with the returning target angle modulation information.
ANGULAR ERROR: The error in angle of an object reported by the antenna.
ANGULAR SEPARATION: This term is frequently used to indicate a protective (from EMI) zone for a missile. The interfering antenna axis must be separated, throughout the critical portion of the missile flight, from the missile by the specified angle. The vertex of the angle is at the interference source antenna.
Next section of "A" terms and definitions
