AI-5
RECEPTION—The instant when an electromagnetic wave passes through a receiver antenna and
induces a voltage in that antenna.
RED—The reference color of equipment that passes classified information. It normally refers to patch
panels.
REPEATER—Another name for an active satellite.
REPERFORATOR—Equipment that converts the incoming tty signal and stores it on paper tape.
REPRODUCTION—The process of converting electrical signals to sound waves. This sound is speech,
music, and so on.
REVERSE AGC—The type of agc that causes an amplifier to be driven toward cut-off.
RUNNING OPEN—The teletypewriter condition where the type hammer constantly strikes the type box
but does not print or move across the page.
SATELLITE ECLIPSE—An eclipse where the rays of the sun don't reach the satellite. This prevents
recharging of the solar cells of the satellite and decreases the power to the transmitter.
SATELLITE-SUN CONJUNCTION—A period when the satellite and sun are close together and the
noise from the sun prevents or hampers communications.
SCANNING—The process of subdividing a picture in an orderly manner into segments. This is used in
facsimile transmission.
SELECTIVITY—The ability of a receiver to select the desired signal and reject unwanted signals.
SENSITIVITY—The ability of a receiver to reproduce very weak signals. The greater the receiver
sensitivity, the weaker the signal that will be reproduced.
SET—A unit or units and the assemblies, subassemblies, and parts connected or associated together to
perform a specific function.
SPACING—The condition in teletypewriter operation where a circuit is open and no current flows.
SQUELCH—A circuit that cuts off the output of a receiver when there is no input.
START—The first unit of a teletypewriter signal. It is always a space.
STOP—The last unit of a teletypewriter signal. It is always a mark.
SUBASSEMBLY—Consists of two or more parts that form a portion of an assembly or a unit.
SUBHARMONIC—An exact submultiple of the fundamental frequency. Even subharmonics are one-
half, one-quarter, and so on. Odd subharmonics are one-third, one-fifth, and so on of the fundamental
frequency.
SUPERHIGH FREQUENCY—The band of frequencies from 3 gigahertz to 30 gigahertz.
SUPPRESSION—The process of eliminating an undesired portion of a signal.
SYNCHRONOUS—A type of teletypewriter operation where both transmitter and receiver operate
continuously.
