1-16
CURRENT STANDING-WAVE RATIO (ISWR)—The ratio of maximum to minimum current along a
transmission line [10].
CUSPS—Sharp phase reversals [12].
CUTOFF—The condition in a tube or transistor whereby the reverse bias prevents current flow [13].
CUTOFF FREQUENCY—The frequency at which the attenuation of a waveguide increases sharply and
below which a traveling wave in a given mode cannot be maintained. A frequency with a half-
wavelength that is greater than the wide dimension of a waveguide [11].
CW DEMODULATOR—A circuit that detects the presence of RF oscillations and converts them into a
useful form [12].
CYCLE—(1) One complete positive and one complete negative alternation of a current or voltage [2] [10].
(2) A 360-degree rotation of a vector generating a sine wave [12].
CYLINDRICAL PARABOLIC REFLECTOR—A parabolically shaped reflector that resembles part of a
cylinder [18].
DAMPED WAVE—A sinusoidal wave in which the amplitude steadily decreases with time. Often
associated with energy loss [9].
DAMPING—(1) The process of smoothing out oscillations. (2) In a meter, this process is used to keep the
pointer of the meter from overshooting the correct reading [3]. (3) A mechanical or electrical technique
used in synchro receivers to prevent the rotor from oscillating or spinning. Damping is also used in
servosystems to minimize overshoot of the load [15] [16].
D'ARSONVAL METER MOVEMENT—The permanent-magnet moving-coil movement used in most
meters [3] [16].
DATA PROCESSING—The execution of a systematic sequence of operations performed upon data.
Synonymous with information processing [13].
DATA TRANSMISSION—The transfer of information from one place to another or from one part of a
system to another [15].
dBm—An abbreviation used to represent power levels above or below a 1-milliwatt reference [16].
DEAD SHORT—A short circuit having minimum resistance [1].
DECIMAL—Pertaining to the number representation system with a radix of ten [13].
DECIMAL DIGIT—In decimal notation, one of the characters 0 through 9 [13].
DECIMAL NOTATION—A fixed radix notation where the radix is ten [13].
DECIMAL NUMERAL—A decimal representation of a number [13].
DECIMAL POINT—The radix point in decimal representation [13].
DECOUPLING CAPACITOR—A capacitor used to transfer unwanted signals out of a circuit; for
example, coupling an unwanted signal to ground. Also called a BYPASS CAPACITOR [8].
DEFLECTION COILS—In a cathode-ray tube, coils used to bend an electron beam a desired amount [18].
