AI-7
SINE WAVE—The basic synchronous alternating waveform for all complex waveforms.
SLOPE DETECTOR—A tank circuit tuned to a frequency, either slightly above or below an fm
carrier frequency, that is used to detect intelligence.
SPACE—Absence of an rf signal in cw keying. Key-open condition or lack of data in
communications systems. Also a period of no signal.
SPARK-GAP MODULATOR—Modulator consists of a circuit for storing energy, a circuit for
rapidly discharging the storage circuit (spark gap), a pulse transformer, and a power source.
SPECTRUM ANALYSIS—The display of electromagnetic energy arranged according to
wavelength or frequency.
SPLATTER—Unwanted sideband frequencies that are generated from overmodulation.
THYRATRON MODULATOR—An electronic switch that requires a low potential to turn it
on.
TRANSMISSION MEDIUM—A means of transferring intelligence from point to point. Can be
described as light, smoke, sound, wirelines, or radio-frequency waves.
UPPER SIDEBAND—All of the sum frequencies above the carrier.
VARACTOR—A diode, or pn junction, that is designed to have a certain amount of capacitance
between junctions.
VARACTOR FM MODULATOR—An fm modulator which uses avoltage-variable
capacitordiode (varactor).
VOLTAGE-DIODE DETECTOR—Series detector in which the crystal is in series with the
input voltage and the load impedance.
VECTOR—Mathematical method of showing both magnitude and direction.
WAVELENGTH—The physical dimension of a sine wave.
