18WuD2x

208 dot • double buffering
length (duration) of a dash. Compare DASH. 2.
One of the small spots of red, green, or blue phosphor
on the screen of a color-television picture
tube or cathode-ray-tube (CRT) computer display.
3. A small spot of material alloyed with a
semiconductor to form an alloy junction. 4. The
junction of two lines on a schematic diagram,
representing a wired connection; also called
solder dot.
dot AND Externally connected circuits or functions
whose combined outputs result in an AND function.
Compare DOT OR.
dot-and-dash telegraphy Telegraphy (wire or radio)
by means of dot and dash characters.
dot cycle One period of an alternation between two
signaling conditions, each of which is of unit duration
(e.g., a unit mark followed by a unit space).
dot encapsulation A method of packaging cylindrical
components by pressing them into the
holes of perforated disks; interconnections are
made, to complete a circuit, on each face of the
disks.
dot generator A special radio-frequency (RF) signal
generator used to produce a pattern of red,
green, and blue dots on the screen of a color television
receiver.
dot matrix A rectangular array of spaces, some of
which are filled in to form alphanumeric and
punctuation characters.
dot matrix
dot-matrix display A display that shows characters
in dot-matrix form.
dot-matrix printer A computer output peripheral
that prints characters and images on paper as a
fine grid of dots. A print head, containing several
pins, presses the ribbon against the paper as it
moves laterally across each line. Can be used to
print text and/or graphics.
dot movement pattern The movement of the red,
green, and blue dots on the screen of a color television
picture tube as the red, green, and blue
magnets and the lateral magnet are adjusted for
convergence of the dots at the center. The blue
dots move horizontally or vertically; the red and
green dots, diagonally.
dot OR Externally connected circuits or functions
whose combined outputs result in an OR function.
Compare DOT AND.
dot pattern In color television testing with a dot
generator, dots of color (a red group, green group,
and blue group) produced on the screen. With
overall beam convergence, the three groups blend
to produce white.
dot-sequential system The color television system
in which the image is reproduced by means of primary-color
dots (red, green, blue) sequentially activated
on the screen of the picture tube.
Compare FIELD-SEQUENTIAL SYSTEM and
LINE-SEQUENTIAL SYSTEM.
double-amplitude-modulation multiplier A modulating
system in which a carrier is amplitudemodulated
first by one signal and then by a second
signal. The resulting signal is fed to a
detector, the output of which contains the product
of the two modulating signals.
double-anode diode A semiconductor diode having
two anodes and a common cathode.
double armature An armature (such as that of a
dynamotor or a two-voltage generator) that has
two separate windings on a single core, and has
two separate commutators.
double-balanced mixer See BALANCED MIXER.
double-balanced modulator See BALANCED
MODULATOR.
double-base diode See UNIJUNCTION TRANSIS-
TOR.
double-base junction transistor A junction transistor
having the usual emitter, base, and collector
electrodes, plus two base connections, one on
either side of the base region. The additional base
connection acts as a fourth electrode to which a
control voltage is applied. Also called tetrode transistor.
double-beam CRT See DUAL-BEAM OSCILLO-
SCOPE.
double-beam oscilloscope See DUAL-BEAM OS-
CILLOSCOPE.
double-bounce calibration In radar operations, a
calibration technique for determining zero-beat
error. Round-trip echoes are observed, the correct
range being the difference between the two
echoes.
double-bounce signal A signal that is received after
having been reflected twice.
double-break contacts The member of a set of
contacts that is normally closed on two others.
Compare DOUBLE-MAKE CONTACTS.
double-break switch A switch that opens a previously
closed circuit at two points simultaneously
on closing. Compare DOUBLE-MAKE SWITCH.
double bridge See KELVIN DOUBLE BRIDGE.
double buffering In the input/output operation of
a computer peripheral, the use of two memory areas
for temporary storage.