CURRENT STANDING-WAVE RATIO (ISWR)The ratio of maximum to minimum current along a
transmission line .
CUSPSSharp phase reversals .
CUTOFFThe condition in a tube or transistor whereby the reverse bias prevents current flow .
CUTOFF FREQUENCYThe 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 .
CW DEMODULATORA circuit that detects the presence of RF oscillations and converts them into a
useful form .
CYCLE(1) One complete positive and one complete negative alternation of a current or voltage  .
(2) A 360-degree rotation of a vector generating a sine wave .
CYLINDRICAL PARABOLIC REFLECTORA parabolically shaped reflector that resembles part of a
DAMPED WAVEA sinusoidal wave in which the amplitude steadily decreases with time. Often
associated with energy loss .
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) 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  .
D'ARSONVAL METER MOVEMENTThe permanent-magnet moving-coil movement used in most
meters  .
DATA PROCESSINGThe execution of a systematic sequence of operations performed upon data.
Synonymous with information processing .
DATA TRANSMISSIONThe transfer of information from one place to another or from one part of a
system to another .
dBmAn abbreviation used to represent power levels above or below a 1-milliwatt reference .
DEAD SHORTA short circuit having minimum resistance .
DECIMALPertaining to the number representation system with a radix of ten .
DECIMAL DIGITIn decimal notation, one of the characters 0 through 9 .
DECIMAL NOTATIONA fixed radix notation where the radix is ten .
DECIMAL NUMERALA decimal representation of a number .
DECIMAL POINTThe radix point in decimal representation .
DECOUPLING CAPACITORA capacitor used to transfer unwanted signals out of a circuit; for
example, coupling an unwanted signal to ground. Also called a BYPASS CAPACITOR .
DEFLECTION COILSIn a cathode-ray tube, coils used to bend an electron beam a desired amount .