ACTIVE SATELLITEA satellite that amplifies the received signal and retransmits it back to earth.
AFDSAn abbreviation for the amphibious flagship data system.
ANGLE OF INCLINATIONThe angular difference between the equatorial plane of the earth and the
plane of orbit of the satellite.
ANTENNA COUPLERA device used for impedance matching between an antenna and a transmitter
APOGEEThe point in the orbit of a satellite the greatest distance from the earth.
ASSEMBLYA number of parts or subassemblies, or any combination thereof, joined together to
perform a specific function.
ASWTDSAn abbreviation for the antisubmarine warfare tactical data system.
ASYNCHRONOUS ORBITOne where the satellite does not rotate or move at the same speed as the
ATDSAn abbreviation for the airborne tactical data system.
AUDIO FREQUENCY TONE SHIFTA system that uses amplitude modulation to change dc mark
and space impulses into audio impulses.
AUTOMATIC TRACKINGTracking done by the equipment comparing the direction of the antenna
axis and the direction of the received signal.
AUTOMATIC VOLUME/GAIN CONTROLA circuit used to limit variations in the output signal
strength of a receiver.
BALANCED PHASE DETECTORA circuit that controls the oscillator frequency (afc).
BAUDA measurement of speed based on the number of code elements or units per second.
BEAT-FREQUENCY OSCILLATORAn additional oscillator used in a receiver when receiving a cw
signal. It provides an audible tone.
BITS-PER-SECONDBit is an acronym of the words binary digit. One bit is equal to one signal unit or
BLACKThe reference color of equipment that passes unclassified information. It normally refers to
CODEIn teletypewriter operation, code is a combination of mark and space conditions representing
symbols, figures, or letters.
COHERENTRadiation on one frequency.