Section I ABBREVIATIONS
DIS disable (squelch)
tp test point
fm frequency modulated
Section II DEFINITION OF UNUSUAL TERMS
CONTROL UNIT. A component of the radio set, located remotely from the receiver-transmitter, to
control the modes of operation, set frequencies, and control squelch modes.
FREQUENCY MODULATION. A type of radio transmission in which the frequency of an rf carrier wave
is varied in accordance with a modulating signal while the amplitude of the carrier wave remains
IMPEDANCE. The opposition of a circuit to the flow of alternating current, measured in ohms.
INTERCOMMUNICATIONS SYSTEM. A configuration of components installed in a aircraft which
permits communications with distant stations and also between crewmembers within aircraft.
OPERATIONAL CHECK. A test or series of tests of a communication system which checks the per-
formance of the communication system and its components under controlled operating conditions to
determine combat readiness of the system.
REFLECTED POWER. The strength of an incoming rf signal passed by a receiver antenna to the
REMOTE CONTROL. The operation of the communication system by remotely located components of
RETRANSMISSION. The arrangement of two radio sets connected together to provide automatic
retransmission of signals between two radios that are too far apart to communicate directly with each
ROUTING. Path taken by cables to interconnect a communications system within a vehicle.
SIDETONE. The sound of user's own voice heard in earphone or loudspeaker while speaking into
SQUELCH. A receiver circuit which automatically turns the sound off when no received signal is
present and turns it on when a received signal is present.
Glossary 1/(Glossary 2 blank)