Page 236 - Electrical Engineering Dictionary
P. 236
dropout equipment misoperation due to DSB See double sideband modulation.
an interruption, noise, or sag.
DSI See discrete sine transform.
dropout compensation signal compen-
sation provided when a loss of information DSL See digital subscriber line.
from magnetic tape defects occurs during
VCR tape playback. Signal dropouts result DSP See digital signal processor.
from oxide or dust interfering with the tape-
head to tape contact when the VCR is in DTE See data terminal equipment.
the record or the playback operational mode.
A horizontal delay line stores the luminance DTW See dynamic time warping.
signal of the previous line that is used to re-
place the lost video information. The sig- dual control an adaptive control that per-
nal dropout is detected as a loss of the tape forms two different functions at the same
playback. FM signal activates an electronic time: one that applies probing signals to
switch. The switch substitutes the stored de- learn more about the system dynamics and
lay line contents into the video path to com- the other that tries to keep the output at a de-
pensate for the lost video from the tape play- sired value.
back.
dual functions mathematical relationship
dropout current the current at which a betweentwosetsusedtorepresentasignal. If
magnetically-operated device will revert to a signal s(t) can be represented by a complete
X
its de-energized position. set {π n (t)}, i.e., s(t) = a n π(t) n , there
n
must exist a dual set {ˆπ n (t)} such that the
dropout voltage the voltage level where
expansion coefficients a n =< s(t), ˆπ n (t) >.
proper equipment operation is hindered.
π n (t) and ˆπ n (t) are called dual functions. As
a special case, if the set {π n (t)} is orthonor-
Drude material a frequency-dependent
mal, then it is its own dual.
dielectric whose complex permittivity is de-
scribed by an equation with two poles, one of
dual in-line package (DIP) a standard
them at w = 0. A collisional plasma is an ex-
case for packaging integrated circuits. The
ample of such a material duration–bandwidth
package terminates in two straight, paral-
reciprocity relation.
lel rows of pins or lead wires. This stan-
dard has been more recently substituted by
Drude media See Drude material.
surface-mount standards. Compare with
single in-line packaging.
drum memory an old form of backing
memory. Similar to magnetic disks in opera- dual mode filters filters realized by us-
tion, but here the magnetic film is deposited ing two resonances inside the same cavity,
on the surface of a drum, instead of a disk. hence allowing saving of space, volume, and
weight.
dry-type transformer a transformer that
is cooled by circulating air or gas through or dual phase-locked loop (DPLL) pro-
around the transformer housing. grammable, low-jitter, low-power, and high-
performance devices. DPPLs are capable
DS-CDMA direct sequence code division of synthesizing two low-jitter clocks with
multiple access. See also direct sequence and user-selected, industry-standard frequencies,
code division multiple access. phased-locked to the system reference tim-
c
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