1-20
DOPING—The process of adding impurities to semiconductor crystals to increase the number of free
charges that can be moved by an external, applied voltage. Doping produces N-type or P-type material
[7] [14].
DOPPLER EFFECT—(1) The apparent change in frequency or pitch when a sound source moves either
toward or away from a listener [10]. (2) In radar, the change in frequency of a received signal caused by
the relative motion between the radar and the target [18].
DOPPLER FREQUENCY—The difference between transmitted and reflected frequencies; caused by the
Doppler effect [18].
DOUBLE-MODING—In a transmitter output tube, the abrupt and random change from one frequency to
another [18].
DOUBLE NEGATIVE LAW—In Boolean algebra, the law which states that the complement of a
complement is the equivalent of the original term [13].
DOUBLE RECEIVER—A fine and coarse synchro receiver enclosed in a common housing with a two-
shaft output (one shaft inside the other) [15].
DOUBLET—Another name for the dipole antenna [10].
DOUBLING UP—This is a type of two-equipment installation where one unit can be substituted for
another in the event of failure [17].
DOWN LINK—The frequency used to transmit an amplified signal from a satellite or other craft back to
earth [17].
DRIFT SPACE—In an electron, a region free of external fields in which relative electron position depends
on velocity [11].
DRIVEN ARRAY—An array in which all of the elements are driven [10].
DRIVEN ELEMENT—The element of an antenna connected directly to the transmission line [10].
DRIVER—The final stage of amplification [8].
DRUM-TYPE ARMATURE—An efficient, popular type of armature designed so that the entire length of
the winding is cutting the field at all times. Most wound armatures are of this type [5].
DRY-AIR SYSTEM—Provides dehumidified air for electronic equipment that is moisture critical [18].
DRY CELL—An electrical cell in which the electrolyte is not a liquid. In most dry cells the electrolyte is in
the form of a paste [1].
DUAL-GATE MOSFET—A two-gate MOSFET in which either gate can control the conductor
independently, a fact which makes this MOSFET very versatile [7].
DUAL IN-LINE PACKAGE (DIP)—IC package having two parallel rows of preformed leads [14].
DUCTILE—Easily drawn out (as to form filaments or wires) [4].
DUCTING—Trapping of an RF wave between two layers of the earth's atmosphere or between an
atmospheric layer and the earth [18].
