ASYMMETRICAL MULTIVIBRATORA multivibrator that generates rectangular waves .
ASYNCHRONOUSThe teletypewriter operation where the transmitter and receiver do not operate
ASYNCHRONOUS ORBITOne where the satellite does not rotate or move at the same speed as the
ATDSAn abbreviation for the airborne tactical data system .
ATTENUATIONThe ability of a filter circuit to reduce the amplitude of unwanted frequencies to a level
below that of the desired output frequency .
ATTRACTIONThe force that tends to make two objects approach each other. Attraction exists between
two unlike magnetic poles (north and south) or between two unlike static charges .
AUDIO AMPLIFIERAn amplifier designed to amplify frequencies between 15 hertz (15 Hz) and 20
kilohertz (20 kHz) .
AUDIO-FREQUENCY-TONE SHIFTA system that uses amplitude modulation to change dc mark and
space impulses into audio impulses .
AUTOMATIC GAIN CONTROLA circuit used to vary radar receiver gain for best reception of signals
that have widely varying amplitudes .
AUTOMATIC TRACKINGTracking done by equipment that compares the direction of the antenna axis
and the direction of the received signal and uses the difference (error) signal to reposition the antenna
AUTOMATIC VOLUME/GAIN CONTROLA circuit used to limit variations in the output signal
strength of a receiver .
AVALANCHE EFFECTA reverse breakdown effect in diodes that occurs at reverse voltages beyond 5
volts. The released electrons are accelerated by the electric field, which results in a release of more
electrons in a chain or "avalanche" effect .
AVERAGE POWER(1) The peak power value averaged over the pulse-repetition time . (2) Output
power of a transmitter as measured from the start of one pulse to the start of the next pulse .
AVERAGE VALUE (OF AC)The average of all the instantaneous values of one-half cycle of alternating
AXISA straight line, either real or imaginary, passing through a body around which the body revolves
AZIMUTHAngular measurement in the horizontal plane in a clockwise direction .
BACK RESISTANCEThe larger resistance value observed when you are checking the resistance of a
BALANCED MIXERA waveguide arrangement that resembles a T and uses crystals for coupling the
output to a balanced transformer .
BALANCED PHASE DETECTORA circuit that controls the oscillator frequency (afc) .