CABLE - Either a stranded conductor (single-conductor cable) or a
combination of conductors insulated from one another (multiple conductor cable). Small
sizes are commonly referred to as stranded wire or as cords .
CABLE HARNESS - A group of wires or ribbons of wiring used to interconnect
electronic systems and subsystems .
CALORIMETER - A device that measures rf power by measuring the heat the rf
power generates.
CAPACITANCE - The property of an electrical circuit that opposes changes
in voltage .
CAPACITIVE REACTANCE - The opposition, expressed in ohms, offered to the
flow of an alternating current by capacitance. The symbol for capacitive reactance is XC .
CAPACITOR - An electrical device capable of storing electrical energy in
an electrostatic field .
CAPACITOR FILTER - This filter is used on extremely high-voltage,
low-current power supplies and also where the ripple frequency is not critical .
CAPACITOR-START MOTOR - A type of single-phase, ac induction motor in
which a starting winding and a capacitor are placed in series to start the motor. The
values of XC and R are such that the main-winding and starting-winding currents are nearly
90 degrees apart and the starting torque is produced as in a two-phase motor .
CARBON MICROPHONE - A microphone in which sound waves vary the resistance
of a pile of carbon granules. May be single-button or double-button .
CARDIOPULMONARY RESUSCITATION - Procedure designed to restore breathing
after cardiac arrest. Includes clearing air passages to lungs and heart massage .
CARRIER FREQUENCY - The frequency of an unmodulated transmitter output .
CARRIER-CONTROLLED APPROACH - A shipboard radar system used to guide
aircraft to safe landings in poor visibility conditions .
CARRY - (1) One or more digits, produced in connection with an arithmetic
operation, that is/are forwarded to another digit place for processing there. (2) The
number represented by the digit or digits in (1) above .
CATCHER GRID - In a velocity-modulated tube, a grid on which the spaced
electron groups induce a signal. The output of the tube is taken from the catcher grid .
CATHODE - (1) In an electron tube the electrode that is the source of
current flow . (2) The general name for any negative electrode . (3) The negative terminal
of a forward-biased semiconductor diode, which is the source of the electrons .
CATHODE BIAS - The method of biasing a vacuum tube in which the biasing
resistor is placed in the common-cathode return circuit, thereby making the cathode more
positive with respect to ground .
CATHODE KEYING - A system in which the cathode circuit is interrupted so
that neither grid current nor plate current can flow .
CATHODE MODULATOR - Voltage on the cathode is varied to produce the
modulation envelope .
CATHODE-RAY TUBE (CRT) - An electron tube that has an electron gun, a
deflection system, and a screen. This tube is used to display visual electronic signals .
CATHODE SPUTTERING - A process of producing thin film components .
CAVITY RESONATOR - A space totally enclosed by a metallic conductor and
supplied with energy in such a way that it becomes a source of electromagnetic
oscillations. The size and shape of the enclosure determine the resonant frequency .
CAVITY WAVEMETER - An instrument used to measure microwave frequencies.
The resonant frequency of the cavity is deter- mined by its inside dimensions.
CELL - A single unit that transforms chemical energy into electrical
energy. Batteries are made up of cells .
CENTER-FEED METHOD - Connecting the center of an antenna to a transmission
line which is then connected to the final (output) stage of the transmitter .
CENTIMETER CUBE - A unit of volume of large rectangular or square
conductors. The cross-sectional area equals 1 square centimeter with a length of 1
centimeter .
CENTRAL PROCESSING UNIT (cpu) - The part of the computer hardware that
directs the sequence of operations, interprets the coded instructions, performs arithmetic
and logical operations, and initiates the proper commands to the computer circuits for
execution. It controls the computer operation as directed by the program it is executing.
CERTIFIED TAPE - A tape that is electrically tested on a specified number
of tracks and is certified by the supplier to have less than a certain total number of
permanent errors.
CERTIFIER - (1) An equipment that tests the ability of magnetic tape to
record and reproduce. (2) Counts and charts each error on the tape, including the level
and duration of dropouts. (3) In the certify mode, stops the tape at an error to allow for
visual inspection of the tape to see if the cause of the error is correctable or
permanent.
CHANNEL - A carrier frequency assignment, usually with a fixed bandwidth .
CHARACTER - A letter, digit, or other symbol that is used as part of the
organization, control, or representation of information .
CHARACTER - One symbol; for example, A, Z, a, z, 0, 1, 9, !, ".
CHARACTERISTIC IMPEDANCE - The ratio of voltage to current at any given
point on a transmission line represented by a value of impedance .
CHARGE - Represents electrical energy. A material having an excess of
electrons is said to have a negative charge. A material having a shortage of electrons is
said to have a positive charge .
CHARGE CYCLE - The period of time that a capacitor in an electrical
circuit is storing a charge .
CHICKEN TRACKS - (1) A line of small craters in the head's top surface
running in the direction of tape motion. (2) Usually caused by a loose, small, hard
particle moving with the tape over the head.
CHIP - A small piece of silicon impregnated with impurities in such a way
as to form transistors, diodes, and resistors. Electrical paths are formed on the silicon
by depositing thin layers of aluminum or gold.
CHOKE - An inductor used to impede the flow of pulsating dc or ac by means
of self-inductance .
CHOKE JOINT - A joint between two sections of waveguide that provides a
good electrical connection without power losses or reflections .
CINCHING - (1) The tape folds resulting from longitudinal slippage between
the layers of tape in a tape pack. (2) Caused by uneven tension when the roll is
accelerated or decelerated.
CIRCUIT - The complete path of an electric current .
CIRCULAR MIL - An area equal to that of a circle with a diameter of 0.001
inch. It is used for measuring the cross-sectional area of wires .
CIRCULAR MIL-FOOT - A unit of volume of a conductor having a
cross-sectional area of 1 circular mil and a length of 1 foot .
CLAMPER - A circuit in which either the upper or lower extremity of a
waveform is fixed at a desired value .
CLASS A AMPLIFIER OPERATION - The type of operation in which the amplifier
is biased so that variations in input signal polarities occur within the limits of cutoff
and saturation .
CLASS AB AMPLIFIER OPERATION - The type of operation in which the
amplifier is biased so that collector current is cut off for a portion of the alternation
of the input signal .
CLASS B AMPLIFIER OPERATION - The type of operation in which the amplifier
is biased so that collector current is cut off for one-half of the input signal .
CLASS C AMPLIFIER OPERATION - The type of operation in which the amplifier
is biased so that collector current is cut off for more than one-half of the input signal
.
CLEAN ROOMS - The rooms of which their cleanliness is measured by the
number of particles of a given size per cubic foot of room volume. (Examples (1) A class
100,000 clean room may have no more than 100,000 particles 0.5 fm or larger per cubic
foot, and so on for class 10,000 and class 100 rooms. (2) A class 10,000 room may have no
more than 65 5-fm particles per cubic foot, while class 100,000 may have no more than 700
5-fm particles per cubit foot.)
CLEANER - (See winder/cleaner.)
CLUTTER - Confusing, unwanted echoes that interfere with the observation
of desired signals on a radar indicator .
COATING - The magnetic layer of a magnetic tape consisting of oxide
particles held in a binder that is applied to the base film.
COATING RESISTANCE - (1) The electrical resistance of the coating measured
between two parallel electrodes spaced a known distance apart along the length of the
tape. (2) Called resistivity on specification sheets.
COATING THICKNESS - The thickness of the magnetic coating applied to the
base film.
COATING-TO-BACKING ADHESION - (See anchorage.)
COAXIAL CABLE - Cable in which the center conductor is separated from an
outer conductor by a dielectric material; used in rf transmission .
COAXIAL LINE - A type of transmission line that contains two concentric
conductors .
COAXIAL-LINE WAVEMETERS - A shorted section of a coaxial line used to
measure rf frequencies. It is calibrated in either wavelength or frequency.
COBOL (COmmon Business Oriented Language) - A high-level programming
language designed for business-type applications.
CODE - In teletypewriter operation, code is a combination of mark and
space conditions representing symbols, figures, or letters .
COEFFICIENT OF COUPLING - An expression of the extent to which two
inductors are coupled by magnetic lines of force. This is expressed as a decimal or
percentage of maximum possible coupling and represented by the letter K .
COHERENCE - A definite phase relationship between two energy waves, such
as transmitted frequency and reference frequency .
COHERENT - Radiation on one frequency .
COHERENT OSCILLATOR - In cw radar an oscillator that supplies phase
References to provide coherent video from target returns .
COIL - An inductive device made by looping turns of wire around a core .
COLD-CATHODE TUBE - A gas-filled electron tube that conducts without the
use of filaments. Cold-cathode tubes are used as voltage regulators .
COLLECTOR - The element in a transistor that collects the current carriers
.
COLLECTOR-INJECTION MODULATOR - The transistor equivalent of a plate
modulator. Modulating voltage is applied to a collector circuit .
COLLINEAR ARRAY - An array with all the elements in a straight line.
Maximum radiation is perpendicular to the axis of the elements .
COMPATIBLE SOFTWARE - Programs that can be run on more than one type of
computer. These programs come in several different versions so they can be run under
several different operating systems.
COMPILER - A program that translates source programs written in a
high-level programming language (for example COBOL or FORTRAN) into machine language.
COMBINATION ARRAY - An array system that uses the characteristics of more
than one array .
COMBINATION CIRCUIT - A series-parallel circuit .
COMBINATION PEAKING - A technique in which a combination of peaking coils
in series and parallel (shunt) with the output signal path is used to improve
high-frequency response .
COMMON BASE - A transistor circuit in which the base electrode is the
common element to both input and output circuits .
COMMON-BASE DETECTOR - An amplifying detector in which detection occurs in
the emitter-base junction and amplification occurs at the output of the collector junction
.
COMMON COLLECTOR - A transistor circuit configuration in which the
collector is the element common to both the input and the output circuits .
COMMON EMITTER - A circuit configuration in which the emitter is the
element common to both the input and the output circuits .
COMMON-EMITTER DETECTOR - Often used in receivers to supply detected and
amplified output. The emitter-base junction acts as the detector .
COMMON IDENTITIES LAW - In Boolean algebra this law states that anytime
the expression A(A + B) = AB or A + AB = A + B appears, it can immediately be simplified
to AB without going through the process of using the distributive law, complementary law,
or the law of union to simplify .
COMMUTATION - The act of a commutator in converting generator output from
an ac voltage to a dc voltage .
COMMUTATIVE LAW - In Boolean algebra this law states that changing the
order of the terms in an equation will not affect the value of the equation. Example: A +
B = B + A; A · B = B · A .
COMMUTATOR - A mechanical device that reverses armature connections in
motors and generators at the proper instant so that current continues to flow in only one
direction. In effect, the commutator changes ac to dc .
COMPARATOR - An equipment that compares incoming signals and selects the
strongest to be fed to a teletypewriter through a patch panel. This is used in diversity
operation .
COMPENSATING WINDINGS - Windings embedded in slots in pole pieces,
connected in series with the armature, whose magnetic field opposes the armature field and
cancels armature reaction .
COMPENSATION - The process of overcoming the problems associated with high
frequencies in an amplifier .
COMPLEMENT - A number or state that is the opposite of a specified number
or state. The negative of a number is often represented by its complement .
COMPLEMENTARY (SECONDARY) COLORS OF LIGHT - The colors of light produced
when two of the primaries are mixed in overlapping beams of light. The complementary
colors of light are magenta, yellow, and cyan .
COMPLEMENTARY LAW - In Boolean algebra this law states that the logical
addition of a quantity and its complement will result in 1 and the logical multiplication
of a quantity and its complement will result in a product of 0 .
COMPLEMENT NUMBER - A number that when added to another number gives a sum
equal to the base of the number system of operation. For example, in the decimal number
system, the complement of 1 is 9 .
COMPLEX WAVE - (1) A waveform other than a sine wave . (2) A wave that is
produced by combining two or more pure tones at the same time .
COMPOUND-WOUND MOTORS AND GENERATORS - Machines that have a series field
in addition to a shunt field. Such machines have characteristics of both series- and
shunt-wound machines .
COMPRESSION WAVES - Longitudinal waves that have been compressed (made
more dense) as they move away from the source .
COMPUTER - A data processor that can perform substantial computation,
including numerous arithmetic or logic operations, without intervention by a human
operator during the run .
COMPUTER OPERATOR - The person who sets up and operates the computer
system.
COMPUTER PROGRAMMER - A person who designs, writes, tests, debugs, and
documents programs.
COMPUTER SYSTEM - The cpu (mainframe) with its console, input, and output
devices, and secondary (auxiliary) storage devices.
COMPUTER USERS - See users.
COMPUTER WORD - See word, computer.
CONCURRENT - Pertaining to the occurrence of two or more events or
activities within the same specified interval of time .
CONDUCTANCE - The ability of a material to conduct or carry an electric
current. It is the reciprocal of the resistance of the material and is expressed in mhos
or siemans .
CONDUCTION BAND - A partially filled energy band in which electrons can
move freely .
CONDUCTIVITY - The ease with which a substance transmits electricity .
CONDUCTOR - (1) A material with a large number of free electrons. (2) A
material that easily permits electric current to flow .
CONDUIT - A tubular raceway, usually metal or plastic, for holding wires
or cables .
CONICAL SCANNING - Scanning in which the movement of the beam describes a
cone, the axis of which coincides with that of the reflector .
CONNECTED ARRAY - Another term for DRIVEN ARRAY .
CONSOLE - The unit of the computer used by the computer operator to
communicate with and control the computer system.
CONTACT - In radar, an object that reflects rf energy; target .
CONTAMINATION - (1) A thick, tacky (viscous) deposit on the head's top
surface, which causes a large increase in the effective head-to-tape coefficient of
friction. (2) May not be removable by solvent cleaning.
CONTINUITY - An uninterrupted, complete path for current flow .
CONTINUOUS-WAVE KEYING - The on-off keying of a carrier .
CONTROL DIFFERENTIAL TRANSMITTER (CDX) - A type of synchro that transmits
angular information equal to the algebraic sum or difference of the electrical input
supplied to its stator, the mechanical input supplied to its stator, and the mechanical
input supplied to its rotor. The output is an electrical voltage taken from the rotor
windings .
CONTROL GRID - The electrode of a vacuum tube, other than a diode, upon
which a signal voltage is impressed to regulate the plate current .
CONTROL-GRID MODULATOR - Uses a variation of grid bias to vary the
instantaneous plate voltage and current. The modulating signal is applied to the control
grid .
CORE MATERIAL - (1) hard core material. - (a) Hard metal laminations
bonded together to form the core, with a typical thickness of 0.005 to 0.004 inch. (Hard
metal wears much more slowly than soft laminations.) (b) Hard solid metal, such as
alphenol or sendust. (Wear rates are much lower than those of soft metal laminations.) (2)
soft core material. - (a) Soft metal laminations bonded together to form the core, with a
typical thickness of 0.0005 to 0.004 inch. (b) Usually, a high nickel/iron alloy, such as
Hy Mu 800. (c) These materials have a relatively poor wear rate.
CONTROL SECTION - The part of the cpu that directs the flow of operations
and data, maintains order in the computer, and initiates execution of the instructions.
CONTROL SYNCHRO SYSTEMS - Synchro systems that contain control synchros
and are used to control large amounts of power with a high degree of accuracy. The
electrical outputs of these systems control servosystems, which in turn generate the
required power to move heavy loads .
CONTROL SYSTEM - A group of components systematically organized to perform
a specific control purpose. These systems are categorized as either closed- or open-loop
systems. The main difference between the two is that the closed-loop system contains some
form of feedback .
CONTROL TRANSFORMER (CT) - A type of synchro that compares two signals:
the electrical signal applied to its stator and the mechanical signal applied to its
rotor. The output is an electrical voltage, which is taken from the rotor winding and is
used to control a power-amplifying device. The phase and amplitude of the output voltage
depends on the angular position of the rotor with respect to the magnetic field of the
stator .
CONTROL TRANSMITTER (CX) - A type of synchro that converts a mechanical
input, which is the angular position of its rotor, into an electrical output signal. The
output is taken from the stator windings and is used to drive either a CDX or CT .
CONVERTER - In communications, equipment that changes the audio output of
a receiver to dc pulses. These pulses are fed to a tty to indicate marks and spaces .
COOKIE-CUTTER TUNER - A mechanical magnetron tuning device that changes
the frequency by changing the capacitance of the anode cavities .
COPPER LOSS (I2R LOSS) - The power lost because of the resistance of the
conductors. In transformers the power lost because of current flow (I) through the
resistance (R) of the windings .
CORDWOOD MODULE - A method of increasing the number of discrete components
in a given space. Resembles wood stacked for a fireplace .
CORE - Any material that affords a path for magnetic flux lines in a coil
.
CORNER-REFLECTOR ANTENNA - A half-wave antenna with a reflector consisting
of two flat metal surfaces meeting at an angle behind the radiator .
CORONA - The discharge of electricity from a conductor with a high
potential .
CORRECTIVE MAINTENANCE - Includes location and repair of equipment
failures .
CORRESPONDENCE - The term given to the positions of the rotors of a
synchro transmitter and a synchro receiver when both rotors are on 0 degree or displaced
from 0 degree by the same angle .
COULOMB - A measure of the quantity of electricity. One coulomb is equal
to 6.28 x 1018 electrons .
COULOMB'S LAW - Also called the LAW OF ELECTRIC CHARGES or the LAW OF
ELECTROSTATIC ATTRACTION. Coulomb's Law states that charged bodies attract or repel each
other with a force that is directly proportional to the product of their individual
charges and inversely proportional to the square of the distance between them .
COUNTER - A circuit that counts input pulses .
COUNTER EMF - The voltage generated within a coil by a moving magnetic
field cutting across the coil itself. This voltage is in opposition (counter) to the
moving field that created it. Counter emf is present in every motor, generator,
transformer, or other inductance winding whenever an alternating current flows .
COUNTERPOISE - A network of wire connected to a quarter-wave antenna at
one end. The network provides the equivalent of an additional one-fourth wavelength .
COUPLING - The process of transferring energy from one point in a circuit
to another point, or from one circuit to another .
COUPLING CAPACITOR - A capacitor used to couple signals .
COUPLING DEVICE - A coupling coil that connects the transmitter to the
feeder .
COVALENT BOND - A type of linkage between atoms in which the atoms share
valence electrons .
CPR - Cardiopulmonary Resuscitation .
CRACK - A narrow, deep break in the head's surface material.
CREEP - The time-dependent strain at a constant stress (tape deformation).
CREST (TOP) - The peak of the positive alternation (maximum value above
the line) of a wave .
CRITICAL ANGLE - The maximum angle at which radio waves can be transmitted
and still be refracted back to earth .
CRITICAL FREQUENCY - The maximum frequency at which a radio wave can be
transmitted vertically and still be refracted back to earth .
CROSS MODULATION - An intermodulation condition that occurs when a carrier
is modulated by an undesired signal.
CROSSFEED - See crosstalk and write feedthrough.
CROSSPLAY - The ability to interchange recordings between recorders while
maintaining a given level of performance.
CROSSTALK - (1) The magnetic coupling from one track to another in the
tape's read/write head. (2) See also write feedthrough.
CROSSED-FIELD AMPLIFIER - A high-power electron tube that converts dc to
microwave power by a combination of crossed electric and magnetic fields .
CROSS-SECTIONAL AREA - The area of a "slice" of an object. When
applied to electrical conductors it is usually expressed in circular mils .
CROWN-OF-THORNS TUNER - See SPROCKET TUNER .
CRT (Cathode-Ray Tube) TERMINAL - A computer terminal that displays its
output on a television-like screen that may be black and white or color.
CRYSTAL - A natural substance, such as quartz or tourmaline, that is
capable of producing a voltage when under physical stress or of producing physical
movement when a voltage is applied .
CRYSTAL FURNACE - A device for artificially growing cylindrical crystals
to be used in the production of semiconductor substrates .
CRYSTAL MICROPHONE - A microphone that uses the piezoelectric effect of
crystalline matter to generate a voltage from sound waves .
CRYSTAL OVEN - A closed oven maintained at a constant temperature in which
a crystal and its holder are enclosed to reduce frequency drift .
CUPPING - (1) The curvature of a magnetic tape pack in the lateral
direction. (2) May be caused by differences between the coefficients of thermal or
hygroscopic expansion of coating and base film.
CURRENT - The movement of electrons past a reference point. The passage of
electrons through a conductor. Measured in amperes .
CURRENT-FEED METHOD - Same as CENTER-FEED METHOD .
CURRENT PROBE - An inductive device used for measuring the current in a
conductor. Probes are designed to be clamped around the insulated conductor.
CURRENT RATING - The safe current-carrying capacity of a wire or cable on
a continuous basis .
CURRENT REGULATOR - A circuit that provides a constant current output .
CURRENT STANDING-WAVE RATIO (ISWR) - The ratio of maximum to minimum
current along a transmission line .
CURRENT TRACER - An inductively coupled device used for tracing current
paths to determine the cause of low-impedance faults on a printed-circuit board.
CURSOR - A pointer (a dot of light) on a crt screen to let you know the
next position in which data will be entered. By depressing cursor control keys, the
operator can move the cursor from line to line and from character to character.
CUSPS - Sharp phase reversals .
CUSTOM SOFTWARE - Programs designed and written to the specifications of a
user or an organization.
CUTOFF - The condition in a tube or transistor whereby the reverse bias
prevents current flow .
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 .
CW DEMODULATOR - A 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 REFLECTOR - A parabolically shaped reflector that
resembles part of a cylinder .
