AI-1
APPENDIX I
GLOSSARY
AMPLITUDE—Used to represent values of electrical current or voltage. The greater its height,
the greater the value it represents.
AMPLITUDE MODULATION—Any method of varying the amplitude of an electromagnetic
carrier frequency in accordance with the intelligence to be transmitted
ANGLE MODULATION—Modulation in which the angle of a sine-wave carrier is varied by a
modulating wave.
AVERAGE POWER—The peak power value averaged over the pulse-repetition time.
BANDWIDTH—The section of the frequency spectrum that specific signals occupy.
BASE-INJECTION MODULATOR—Similar to control-grid modulator. Gain of a transistor is
varied by changing the bias on its base.
BLOCKED-GRID KEYING—A method of keying in which the bias is varied to turn plate
current on and off.
BUFFER—A voltage amplifier used between the oscillator and power amplifier.
CARBON MICROPHONE—Microphone in which sound waves vary the resistance of a pile of
carbon granules. May be single-button or double-button.
CARRIER FREQUENCY—The assigned transmitter frequency.
CARRIER—Radio-frequency sine wave.
CATHODE KEYING—A system in which the cathode circuit is interrupted so that neither grid
current nor plate current can flow.
CATHODE MODULATOR—Voltage on the cathode is varied to produce the modulation
envelope.
CHANNEL—Carrier frequency assignment usually with a fixed bandwidth.
COLLECTOR-INJECTION MODULATOR—Transistor equivalent of plate modulator.
Modulating voltage is applied to collector circuit.
COMMON-BASE DETECTOR—An amplifying detector where detection occurs in
emitter-base junction and amplification occurs at the output of the collector junction.
COMMON-EMITTER DETECTOR—Often used in receivers to supply detected and
amplified output. The emitter-base junction acts as the detector.
COMPLEX WAVE—A wave composed of two or more parts.
CONTINUOUS-WAVE KEYING—The "on-off" keying of a carrier.
