Page 234 - Electrical Engineering Dictionary
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double heterostructure dye laser  laser in  double-sided assembly  a packaging and
                              which the amplification takes place in a dye;  interconnecting structure with components
                              a broadly tunable laser.               mounted on both the primary and secondary
                                                                     sides.
                              double lambda system   a quantum me-
                              chanical system composed of two interact-  double-sided disk  a disk in which both
                              ing lambda systems that share common lower  sides of a platter are covered with magnetic
                              states. A double lambda system is also a dou-  material and used for storing information.
                              ble vee system. Double lambda systems can
                              be used to construct resonant closed loop in-  doublet  a system of two quadrupole mag-
                              teractions in which some linear combination  nets in close proximity and with opposite
                              of the phases of the four fields is constant in  polarity used to simultaneously constrain
                              time.                                  the beam size in two dimensions at some
                                                                     point downstream. Doublet (Quadrupole)
                                                                     is a beam optical system consisting of two
                              double line to ground fault  See double
                                                                     quadrupoles of opposite sign, which provides
                              phase ground fault.
                                                                     net particle focusing in all planes.
                              double phase ground fault  a fault with
                                                                     doubly-fed induction motor  an induc-
                              two transmission lines being connected to the
                                                                     tion motor with a wound-rotor. The rotor
                              ground.
                                                                     and stator windings are connected to sepa-
                                                                     rate sources of electric energy. The machine
                              doublerevolving-fieldtheory  Seecounter-
                                                                     can be used as a generator to provide fre-
                              rotating field theory.
                                                                     quency conversion or precise speed control
                                                                     in the motor-mode.
                              double sideband modulation (DSB)  a
                              modulation scheme resulting in a spectrum  down-sampling  See decimation.
                              consisting of the carrier frequency, one signal
                              that is the sum of the carrier and the modu-  downconductor  the cable which connects
                              lating signal, and one signal that is the differ-  anairterminalorlightningrodtoground. See
                              ence between the carrier and the modulating  air terminal.
                              signal.
                                                                     download   to bring data from a remote
                              double tuned  a circuit, amplifier, or other  source to local storage.
                              device having a response that is the same as
                              two single-tuned circuits.             downstream   in power distribution work,
                                                                     the direction in which power flows, i.e., to-
                                                                     wards the load.
                              double word    data block that contains
                              twice the number of bits as the machine word
                                                                     DPA    See destructive physical analysis.
                              size in a microprocessor.
                                                                     DPCM       See differential pulse code
                              double-cage rotor  See dual-cage rotor.
                                                                     modulation.
                              double-frequencyrecording  Seemagnetic  DPCM encoding    See differential pulse
                              recording code.                        code modulation.

                              double-line contingency  a malfunction  DPI  See dots per inch.
                              of a power system which involves the simul-
                              taneous failure of two transmission lines.  DPLL  See dual phase-locked loop.



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