D-F Flashcards
Contains common communication terms starting with letter D up to letter F. Taken from Comms Dictionary (124 cards)
1
Q
A sinusoidal wave in which the amplitude steadily decreases with time. Often associated with energy loss.
A
Damped Wave
2
Q
- The process of smoothing out oscillations
- In a meter, this process is used to keep the pointer of the meter from overshooting the correct reading
- a mechanical or electrical technique used in synchronous receivers to prevent the rotor from oscillating or spinning. It is also used in servo systems to minimize overshoot of the load.
A
Damping
3
Q
Facts represented by numbers, letters, or symbols to which meaning is or can be assigned.
A
Data
4
Q
A structured collection of data that can e extracted, organized, and manipulated by a program
A
Data Base
5
Q
A short circuit having minimum resitance
A
Dead Short
6
Q
The process of finding errors (bugs) in a program or system and correcting them so that the program or system runs correctly.
A
Debugging
7
Q
Feedback in which the feedback signal is out of phase with the input signal.
A
Degenerative Feedback
AKA Negative Feedback
8
Q
a three-phase connection in which windings are connected end-to-end, forming a closed loop. A separate phase wire is then connected to each of the three junctions.
A
Delta
9
Q
The removal of intelligence from a transmission medium.
A
Demodulation
10
Q
Operational phase of a fire-control or track radar during which the radar is directed to the general direction of a desired target.
A
Designation
11
Q
The separation of low-frequency (audio) intelligence from the high-frequency carrier
A
Detection
12
Q
An insulator; a term applied to the insulating material between the plates of a capacitor
A
Dielectric
13
Q
A circuit that amplifies the difference between two input signals
A
Differential Amplifier
14
Q
The ability of an antenna to radiate or receiver more energy in some directions than in others. The degree of sharpness of the antenna beam
A
Directivity
15
Q
The parasitic element of an array that reinforces energy coming from the driver element
A
DDirector
16
Q
A circuit in which amplitude variation s are derived in response to phase or frequency vatiations
A
Discriminator
17
Q
The refraction of light waves that cases the different frequencies to bend at slightly different angles
A
Dispersion
18
Q
Any unwanted change between an input signal and output signal
A
Distortion
19
Q
The easiest mode to produce in a wave guide, and the most efficient mode in terms of energy transfer
A
Dominant Mode
20
Q
An impurity that can make a semiconductor material an N-type by donating extra “free” electrons to the conduction band.
A
Donor
21
Q
- The apparent change in frequency or pitch when a sound source moves either toward or away from a listener
- in radar, the change in frequency of a received signal caused by the relative motion between the radar and the target
A
Doppler Effect
22
Q
The difference between transmitted and reflected frequencies;
A
Doppler Frequency
23
Q
Another name for the dipole antenna
A
Doublet
24
Q
The length of time the computer is note operating, either because of preventive maintenance or a malfunction
A
Down Time
25
The frictional tension differential across the contact area caused when the tape contacts some element in the tape path.
Drag
26
The final stage of amplificatin
Driver
27
Provides dehumidified air for electronic equipment that is moisture critical
Dry-Air System
28
An electrical cell in which the electrolyte is not a liquid, instead, it is commonly a paste.
Dry Cell
29
Easily drawn out as to form filaments or wires
Ductile
30
Trapping of an rf wave between two layers of the earth's atmosphere or between an atmospheric layer and the earth
Ducting
31
A dissipative but nonradiating device that has the impedance characteristics of an antenna or transmission line
Dummy Load
| AKA Artificial Load
32
In a transmitter, ratio of time on to time off
Duty Cycle
33
1. The bandwidth within which a satisfactory signal-to-noise ratio is obtained
Dynamic Range
34
An 8-bit coding system for representing uppercase and lower case letters, numbers and special characters.
EBCDIC (Extended Binary Coded Decimal Interchange Code)
35
A resonant cavity device that is used to check the overall performance of a radar system. It receives a portion of the transmitted pulse and re transmits it back to the receiver as a slowly decaying transient.
Echo box
36
A condition in which the satellite is not in view or in direct line of sight with the sun. This happens when the earth is between them.
Eclipse
37
The phenomenon wherein electrons emitted from a heated element with a vacuum tube will flow to a second element that is connected to a positive potential
Edison Effect (Richardson effect)
38
Field that exists when a difference in electrical potential causes a stress in the dielectric between two points.
E-field
39
Electric energy stored on or in an object. The negative charge is caused by an excess of electrons; the positive charge is caused by a deficiency of electrons
Electrical Charge
40
A synchro zeroing method. This method is used only when the rotors of the synchros to be zeroed are free to turn and their leads are accessible
Electrical Lock
41
A standard synchro position, with a definite set of stator voltages, that is used as the reference point for alignment of all synchro units
Electrical Zero
42
The terminal at which electricity passes from one medium into another, such as in an electrical cell where the current leaves or returns to the electrolyte
Electrode
43
A meter movement using fixed field coils and a moving coil; usually used in ammeters and wattmeters.
Electrodynamic Meter Movement
44
A meter using an electrodynamic movement to measure an electric current
Electrodynamometer
45
The process of changing the chemical composition of a material by passing an electric current through it.
Electrolysis
46
An electrically excited magnet capable of exerting mechanical force or of performing mechanical work
Electromagnet
47
The combination of an electric field and a magnetic fiedl
Electromagnetic Field
48
Man-made or natural interference that degrades the quality of reception of radio waves.
Electromagnetic Interference
49
The generation of a magnetic field around a current-carrying conductor
Electromagnetism
50
The force (voltage) that produces an electric current in a circuit
Electromotive Force
51
The elementary negative charge that revolves around the nucleus of an atom
Electron
52
The movement of an electron around the nucleus of an atom
Electron Orbital movement
53
A group of electrons which have a common energy level that forms part of the outer structure (shell) of an atom
Electron Shell
54
A device that provides an alternate dry-air input in the event of failure of the central dry-air system. It may include a compressor
Electronic Equipment Degydrator
55
An instrument that counts the number of cycles (pulses) occurring during ta precise time interval.
Electronic Frequency Counter
56
A circuit that causes a start-and-stop switching action by electronic means
Electronic Switch
57
A common line for providing dry air to various electronic equipment, such as search radar, fire-control radar and repeaters
Electronics Dry-Air Branch
58
In a reflex klystron, changing the frequency and output power of the tube by altering the repeller voltage
Electronic Tuning
59
The movement of an electron around its axis
Electron Spin
60
Pertaining to electricity at rest, such as charges on an object.
Electrostatic
61
Electronic components that are susceptible to damage from static charges
Electrostatic-Discharge Sensitive (ESDS) Device
62
A meter movement that uses the electrostatic repulsion of two sets of charged plates. This meter movement reacts to voltage rather than to current and is used to measure high voltage
Electrostatic Meter Movement
63
The force exerted on an insulator by the voltage in a conductor
Electrostatic Stress
64
1. A substance, in chemistry, that cannot be divided into simpler substances by any means ordinarily available
2. A part of an antenna that can be either an active radiator a parasitic radiator
Element
65
Ducting used for ventilation purposes
Elephant Trunk
66
Temporary source of limited electrical power used upon the loss of the normal power source
Emergency Power
67
The force that causes electricity to flow between two points with different electrical charges or when there is a difference of potential between the two points.
EMF (Electromotive Force)
68
The transistor equivalent of the cathode modulator. The gain is varied by changing the voltage on the emitter
Emitter-Injection Modulator
69
A synthetic compound of cellulose acetate (wood pulp and magnesium). Used to insulate wire in meters, relays, and motor windings.
Enamel
70
Embedded in solid material or enclosed in glass ro metal
Encapsulalted
71
A method in which one end of an antenna is connected through a capacitor to the final output stage of a transmitter.
End-feed Method
72
An array in which the direction of radiation is parallel to the axis of the array
End-Fire Array
73
A table showing the precalculated position of a satellite at any given time
Ephemeris
74
The acronym for erasable programmable read-only memory
EPROM
75
A resistance that represents the total ohmic values of a circuit component or group of circuit components. usually drawn as a single resistor in a simplified circuit
Equivalent Resitance (Req)
76
A process by which a signal recorded on a tape is removed and the tape made ready for rerecording
Erasure
77
The name commonly given to the servomotor in a servo system. So named because it reduces the error signal by providing feedback to the error detector.
Error Reducer
78
1. in servosystems, the signal whose amplitude and polarity or phase are used to correct the alignment between the controlling and the controlled elements.
2. The name given to the electrical output of a control transforemer
Error Signal
79
An alloy that changes directly from a solid to a liquid with no plastic or semiliquid state
Eutectic Alloy
80
The current that flows in the primary winding of a transformer when the secondary is open-circuited; it produces a magnetic flux field.
Exciting Current
| AKA magnetizing current
81
A function whose output is a 1 if one and only one of the input variables is a 1
Exclusive OR
82
A semiconductor in which impurities have been added to create certain charge carrier concentrations
Extrinsic
83
The method for transmitting and receiving still images. These images can be maps, photographs, and handwritten or printed text
Facsimile
84
Any of the elements, quantities, or symbols that, when multiplied together, form a product
Factor
85
Variations in signal strength by atmospheric conditions
Fading
86
The rotation of the plane of polarization of electromagnetic energy when it passes a substance influenced by a magnetic field that has a component in the direction of progagation
Faraday Rotation
87
Differentiator circuit in the first video amplifier that allows only the leading edges of target returns, no matter how small or large
Fast-Time-Constant Circuit
88
A transmission line that carrier energy to the natenna
Feeder
89
A horn radiator used to feed a reflector
Feed Horn
90
A powdered and compressed ferric oxide material that has both magnetic properties and light resistance to current flow
Ferrite
91
An outer covering used to protect a conductor's insulating material. Commonly made from cotton, linen, silk, rayon, or fiberglass.
Fibrous Braid
92
1. The faithful reproduction of a signal
2. The accuracy with which a system reproduces a signal at its otput that faithfully maintains the essential characteristics of the input signal
Fidelity
93
A transistor consisting of a source, a gate, and a drain. Current flow is controlled by the transverse electric field under the agate
Field Effect Transistor
94
A term used to describe the total force exerted by an action-at-a-distance phenomenon such as gravity upon matter, electric charges acting upon electric charges, and magnetic forces acting upon other magnets or magnetic materials
Field of Force
95
A selective network of resistors, capacitors, and inductors that offers comparatively little opposition to certain frequencies, while blocking or attenuating other frequencies
Filter
96
The final stage of amplification in a transmitter
Final Power Amplifier (FPA)
97
A set of program instructions, a microprogram, permanently stored in a read-only memory.
Firmware
98
A device used to discharge the pulse-forming network. A trigger pulse ionize s the air between two contacts to initiate the discharge.
Fixed Spark Gap
99
A transmission line that has no standing waves. This line requires no special timing devices to transfer maximum power
Flat Line
100
An earlier name for a diode, or a two-electrode vacuum tube used as a detector.
Fleming Valve
101
A line made with an inner conductor that consists of flexible wire insulated from the outer conductor by a solid, continuous insulating aterial
Flexible Coaxial ine
102
A device having two stable states and two input terminals, each of which corresponds with one of the two states. The circuit remains in either state until caused to change to the other state by application of a voltage pulse. A similar bistable device with an input that allows it to act a s a single-stage binary counter
Flip-Flop
103
A graphic represntation of the processing steps (logic_ of a program ( a program flowchart) or the inputs, outputs, and processing steps of a system. The graphic representation uses symbols to represent operations and directional lines to indicate sequence and direction of flow
Flowchart
104
1. In electrical or electromangetic devices, a general term used to designate collectively all the electric or magnetic lines of force in a region
2. A solution that removes surface oxides from metals being soldered.
Flux
105
The ability of a resonant circuit to operate continuously because of stored energy or energy pulses
Flywheel effecst
106
The energy band in an atom lying between the conduction band and the valence band. Electrons are never found in the forbidden band but may travel back and forth trough it. The forbidden band determines whether a solid material will act as a conductor, a semi-conductor, or an insulator.
Forbidden Band
107
An external voltage that is applied to a PN junction in the conducting direction so that the junction offers only minimum resistance to the flow of current. Conduction is accomplished by majority current carriers (hole in P=type material; electrons in N-type material)
Forward Bias
108
The smaller resistance value observed when you are checking the resistance of a semcionductor
Forward Resistance
109
A circuit that uses a double-tuned rf transformer to convert frequency variations in tree received fm signal to amplitude variations
Foster-Seeley Discriminator
| AKA Phase-Shift Discriminator
110
The process of synchroning a facsimile receiver to transmitter. This allows proper picture reproudction.
Framing
111
The loss of energy of radio waves caused by the spreading of the wavefront as it travels from the transmitter.
Free-Space Loss
112
Circuit modification used to improve or broaden the linearity of its frequency response
Frequency Compensation Network
113
The frequency at which the filter circuit changes from an action of rejecting the unwanted frequencies to an action of passing the desired frequencies. Conversely, the point at which the filter circuit changes from an action in which it passes the desired frequencies to an action in which it rejects the undesired frequencies.
Frequency Cutoff
114
Refers the the difference between the carrier frequency of an fm signal and the instantaneous frequency of its modulated wave.
Frequency Deviation
115
1. The ability to a component or device to operate over a portion of the frequency spectrum.
2 In reference to test equipment, that portion of the frequency spectrum that the test equipment is capable of sensing and and measuring accurately
Frequency Response
116
A curve showing the output of an amplifier in terms of voltage or current plotted against frequency with a fixed-amplitude input singla
Frequency-Response Curve
117
Varying the output frequency to achieve electronic scanning
Frequency Scanning
118
Frequency modulation somewhat similar to continuous-wave keying in AM transmitters. The carrier is shifted between two differing frequencies by opening and closing a key
Frequency-Shfirt Keying
119
Refers tot he ability of an oscillator to accurately maintain its operating frequency
Frequency stability
120
The ratio of the energy radiated in the principal direction compared to the energy radiated in the opposite direction
Front-to-back Ratio
121
A circuit that uses the positive and negative alternation s in an alternating current to produce direct current
Full-wave Rectifier
122
Consists of tow half-wave voltage rectifiers and is used to reduce the output ripple amplitude
Full-wave Voltage Doubler
123
A specific purpose of an entity; its characteristic action
Function
124
The basic frequency or first harmonic freuqncy
Fundamental Frequency
