SINE WAVEThe basic synchronous alternating waveform for all complex waveforms.
SLOPE DETECTORA tank circuit tuned to a frequency, either slightly above or below an fm
carrier frequency, that is used to detect intelligence.
SPACEAbsence 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 MODULATORModulator 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 ANALYSISThe display of electromagnetic energy arranged according to
wavelength or frequency.
SPLATTERUnwanted sideband frequencies that are generated from overmodulation.
THYRATRON MODULATORAn electronic switch that requires a low potential to turn it
TRANSMISSION MEDIUMA means of transferring intelligence from point to point. Can be
described as light, smoke, sound, wirelines, or radio-frequency waves.
UPPER SIDEBANDAll of the sum frequencies above the carrier.
VARACTORA diode, or pn junction, that is designed to have a certain amount of capacitance
VARACTOR FM MODULATORAn fm modulator which uses avoltage-variable
VOLTAGE-DIODE DETECTORSeries detector in which the crystal is in series with the
input voltage and the load impedance.
VECTORMathematical method of showing both magnitude and direction.
WAVELENGTHThe physical dimension of a sine wave.