Electronics Flashcards
(104 cards)
1
Q
Type of electrical current, in which the direction of the flow of electrons switches back and forth at regular intervals or cycles.
Current flowing in power lines and normal household electricity that comes from a wall outlet is ___. The standard current used in the U.S. is 60 cycles per second (i.e. a frequency of 60 Hz); in Europe and most other parts of the world it is 50 cycles per second (i.e. a frequency of 50 Hz.).
A
Alternating Current (AC)
2
Q
The ___ of a periodic variable is a measure of its change over a single period (such as time or spatial period). There are various definitions of ___, which are all functions of the magnitude of the difference between the variable’s extreme values. In older texts the phase is sometimes called the ___.
A
Amplitude
3
Q
For signals that have not been digitized, as in legacy radio, telephone, radar, and television systems.
A
Analog signal processing
4
Q
Is an integrated circuit (IC) customized for a particular use, rather than intended for general-purpose use. For example, a chip designed to run in a digital voice recorder or a high-efficiency bitcoin miner is an ___. Application-specific standard products (ASSPs) are intermediate between ___ and industry standard integrated circuits like the 7400 series or the 4000 series.
As feature sizes have shrunk and design tools improved over the years, the maximum complexity (and hence functionality) possible in an ___ has grown from 5,000 logic gates to over 100 million. Modern ___ often include entire microprocessors, memory blocks including ROM, RAM, EEPROM, flash memory and other large building blocks. Such an ___ is often termed a SoC (system-on-chip). Designers of digital ___ often use a hardware description language (HDL), such as Verilog or VHDL, to describe the functionality.
A
Application-specific integrated circuit (ASIC)
5
Q
In computing, it is the maximum rate of data transfer across a given path.
In signal processing, wireless communications, modem data transmission, digital communications, and electronics, it is used to refer to analog signal measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power.
A
Bandwidth
6
Q
In telecommunication and electronics, ___ is a common measure of symbol rate, one of the components that determine the speed of communication over a data channel.
It is the unit for symbol rate or modulation rate in symbols per second or pulses per second. It is the number of distinct symbol changes (signaling events) made to the transmission medium per second in a digitally modulated signal or a ___ rate line code.
A
Baud (/bɔːd/; symbol: Bd)
7
Q
A construction base for prototyping of electronics. Originally it was literally a polished piece of wood used for slicing bread. In the 1970s the solderless ___ became available and nowadays the term is commonly used to refer to these.
A
Breadboard (a.k.a. plugboard, a terminal array board)
8
Q
A communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components (wire, optical fiber, etc.) and software, including communication protocols.
Early computer ___ were parallel electrical wires with multiple hardware connections, but the term is now used for any physical arrangement that provides the same logical function. Modern computer ___ can use both parallel and bit serial connections, and can be wired in either a multidrop (electrical parallel) or daisy chain topology, or connected by switched hubs, as in the case of USB.
A
Bus (a contraction of the Latin omnibus)
9
Q
The electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions
A
Central Processing Unit (CPU)
10
Q
In digital communications, ___ is a spread spectrum technique that uses wideband linear frequency modulated chirp pulses to encode information. A chirp is a sinusoidal signal of frequency increase or decrease over time (often with a polynomial expression for the relationship between time and frequency).
A
Chirp spread spectrum (CSS)
11
Q
A method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (___) through the network before the nodes may communicate. The ___ guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The ___ functions as if the nodes were physically connected as with an electrical ___.
The defining example of a ___ is the early analog telephone network. When a call is made from one telephone to another, switches within the telephone exchanges create a continuous wire ___ between the two telephones, for as long as the call lasts.
A
Circuit-switched network
12
Q
Refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking.
This is used to convey an information signal, for example a digital bit stream, from one or several senders (or transmitters) to one or several receivers.
A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second.
A
Communication channel, or simply channel
13
Q
An object or type of material that allows the flow of an electrical current in one or more directions.
A
Conductor
14
Q
___ occurs when the phase difference between the waves is an even multiple of π (180°)
A
Constructive interference
15
Q
Means the rate at which process progressing is limited by the speed of the ___. A task that performs calculations/operations on a small set of numbers, for example multiplying small matrices, is likely to be ___.
A
CPU Bound
16
Q
___ is the flow of Electric Charge.
___ = Charge / Time
___ = Coulomb per Second
A
Current (Amperes or Amps)
17
Q
___ take one data input and a number of selection inputs, and they have several outputs. They forward the data input to one of the outputs depending on the values of the selection inputs. ___ are sometimes convenient for designing general purpose logic, because if the ___ input is always true, the ___ acts as a binary decoder. This means that any function of the selection bits can be constructed by logically OR-ing the correct set of outputs.
A
Demultiplexer (or demux)
18
Q
___ is an electronic (solid-state) non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of ___ are named after the NAND and NOR logic gates. The individual ___ cells, consisting of floating-gate MOSFETs (floating-gate metal-oxide-semiconductor field-effect transistors), exhibit internal characteristics similar to those of the corresponding gates.
___ is a type of floating-gate memory that was invented at Toshiba in 1980, based on EEPROM (electrically erasable programmable read-only memory) technology.
A
Flash memory
19
Q
___ occurs when the phase difference between the waves is an odd multiple of π (180°)
A
Destructive interference
20
Q
The processing of digitized discrete-time sampled signals. Processing is done by general-purpose computers or by digital circuits such as ASICs, field-programmable gate arrays or specialized digital signal processors (DSP chips).
A
Digital signal processing
21
Q
A two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other.
A
Diode
22
Q
Electrical current which flows consistently in one direction.
The current that flows in a flashlight or another appliance running on batteries is ___.
A
Direct current (DC)
23
Q
A point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. ___ systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field.
A
Duplex communication system
24
Q
___ is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.
A
Electric charge
25
An ___ surrounds an electric charge, and exerts force on other charges in the field, attracting or repelling them. The ___ is defined mathematically as a vector field that associates to each point in space the (electrostatic or Coulomb) force per unit of charge exerted on an infinitesimal positive test charge at rest at that point. The SI unit for ___ strength is volt per meter (V/m). Newtons per coulomb (N/C) is also used as a unit of ___ strength. ___ are created by electric charges, or by time-varying magnetic fields. ___ are important in many areas of physics, and are exploited practically in electrical technology.
Electric field (sometimes abbreviated as E-field)
26
In physics, ___ refers to the waves (or their quanta, photons) of the ___ field, propagating (radiating) through space, carrying ___ energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays.
Electromagnetic radiation (EM radiation or EMR)
27
The ___ is the range of frequencies (the ___) of electromagnetic radiation and their respective wavelengths and photon energies.
The ___ covers electromagnetic waves with frequencies ranging from below one hertz to above 10 to the power of 25 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the ___ these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications. The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length. Gamma rays, X-rays, and high ultraviolet are classified as ionizing radiation as their photons have enough energy to ionize atoms, causing chemical reactions.
Electromagnetic spectrum
28
___ is a branch of physics involving the study of the ___, a type of physical interaction that occurs between electrically charged particles. The ___ is carried by ___ fields composed of electric fields and magnetic fields, and it is responsible for ___ radiation such as light. It is one of the four fundamental interactions (commonly called forces) in nature, together with the strong interaction, the weak interaction, and gravitation. At high energy the weak force and ___ are unified as a single electroweak force.
Electromagnetism (electromagnetic force)
29
An electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave. This converts direct current (DC) from a power supply to an alternating current (AC) signal. They are widely used in many electronic devices. Common examples of signals generated by ___ include signals broadcast by radio and television transmitters, clock signals that regulate computers
Electronic oscillator
30
___ is the capacity to do work.
Energy (kcal - Calorie, J - Joule, kWh - kilowatt-hour)
31
The International Telecommunication Union (ITU) designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band, and the far infrared band, the lower part of which is also referred to as the terahertz gap. Radio waves in this band have wavelengths from ten to one millimetre, so it is also called the millimetre band and radiation in this band is called millimetre waves, sometimes abbreviated MMW or mmW or mmWave. Millimetre-length electromagnetic waves were first investigated in the 1890s by Indian scientist Jagadish Chandra Bose.
Extremely high frequency (EHF)
32
In digital electronics, the ___of a logic gate output is the number of gate inputs it can drive.
In most designs, logic gates are connected to form more complex circuits. While no logic gate input can be fed by more than one output, it is common for one output to be connected to several inputs. The technology used to implement logic gates usually allows a certain number of gate inputs to be wired directly together without additional interfacing circuitry. The maximum ___ of an output measures its load-driving capability: it is the greatest number of inputs of gates of the same type to which the output can be safely connected.
Fan-out
33
Is an integrated circuit designed to be configured by a customer or a designer after manufacturing - hence the term "___". The ___ configuration is generally specified using a hardware description language (HDL), similar to that used for an Application-Specific Integrated Circuit (ASIC). Circuit diagrams were previously used to specify the configuration, but this is increasingly rare due to the advent of electronic design automation tools.
Field-programmable gate array (FPGA)
34
In telecommunications and signal processing, ___ modulation is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave.
In analog ___ modulation, such as ___ radio broadcasting of an audio signal representing voice or music, the instantaneous frequency deviation, the difference between the frequency of the carrier and its center frequency, is proportional to the modulating signal.
Frequency modulation (FM)
35
A ___, is one of a series of confocal prolate ellipsoidal regions of space between and around a transmitter and a receiver. Transmitted radio, sound, or light waves can follow slightly different paths before reaching a receiver, especially if there are obstructions or reflecting objects between the two. The waves can arrive at slightly different times and will be slightly out of phase due to the different path lengths. Depending on the magnitude of the phase shift, the waves can interfere constructively and destructively. The size of the calculated ___ at any particular distance from the transmitter and receiver can help to predict whether obstructions or discontinuities along the path will cause significant interference.
Fresnel zone, named after physicist Augustin-Jean Fresnel
36
In a ___, both parties can communicate with each other simultaneously. An example of a ___ device is a telephone; the parties at both ends of a call can speak and be heard by the other party simultaneously. The earphone reproduces the speech of the remote party as the microphone transmits the speech of the local party, because there is a two-way communication channel between them, or more strictly speaking, because there are two communication channels between them.
Full-duplex system
37
Is a packet oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications (GSM). ___ was established by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP).
The ___ core network allows 2G, 3G and WCDMA mobile networks to transmit IP packets to external networks such as the Internet.
General Packet Radio Service (GPRS)
38
Is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile devices such as mobile phones and tablets. It was first deployed in Finland in December 1991. By the mid-2010s, it became a global standard for mobile communications achieving over 90% market share, and operating in over 193 countries and territories.
2G networks developed as a replacement for first generation (1G) analog cellular networks. The ___ standard originally described a digital, circuit-switched network optimized for full duplex voice telephony. This expanded over time to include data communications, first by circuit-switched transport, then by packet data transport via General Packet Radio Service (GPRS), and Enhanced Data Rates for ___ Evolution (EDGE).
Subsequently, the 3GPP developed third-generation (3G) UMTS standards, followed by fourth-generation (4G) LTE Advanced standards, which do not form part of the ETSI __ standard.
Global System for Mobile Communications (GSM)
39
The reference point in an electrical circuit from which voltages are measured
A common return path for electric current
A direct physical connection to the earth.
Ground or Earth
40
In a ___, both parties can communicate with each other, but not simultaneously; the communication is one direction at a time. An example of a ___ device is a walkie-talkie two-way radio that has a "push-to-talk" button; when the local user wants to speak to the remote person they push this button, which turns on the transmitter but turns off the receiver, so they cannot hear the remote person. To listen to the other person they release the button, which turns on the receiver but turns off the transmitter.
Half-duplex system
41
In computer engineering, a ___ is a specialized computer language used to describe the structure and behavior of electronic circuits, and most commonly, digital logic circuits.
A ___ enables a precise, formal description of an electronic circuit that allows for the automated analysis and simulation of an electronic circuit. It also allows for the synthesis of a ___ description into a netlist (a specification of physical electronic components and how they are connected together), which can then be placed and routed to produce the set of masks used to create an integrated circuit.
A ___ looks much like a programming language such as C; it is a textual description consisting of expressions, statements and control structures. One important difference between most programming languages and ___ is that ___ explicitly include the notion of time.
___ form an integral part of electronic design automation (EDA) systems, especially for complex circuits, such as application-specific integrated circuits, microprocessors, and programmable logic devices.
Hardware description language (HDL)
42
___ is a family of IEEE standards dealing with local area networks and metropolitan area networks.
The ___ standards are restricted to networks carrying variable-size packets, unlike cell relay networks, for example, where data is transmitted in short, uniformly sized units called cells.
The number ___ has no particular significance: it was simply the next available number IEEE could assign to the standards project, although ___ is sometimes associated with February 1980, the date of the first meeting.
The services and protocols specified in ___ map to the lower two layers (Data Link and Physical) of the seven-layer OSI networking reference model. In fact, ___ splits the OSI Data Link Layer into two sub-layers named logical link control (LLC) and media access control (MAC), so the layers can be listed like this:
- Data link layer
- - LLC sublayer
- - MAC sublayer
- Physical layer
The ___ family of standards is maintained by the ___ LAN/MAN Standards Committee (LMSC). The most widely used standards are for the Ethernet family, Token Ring, Wireless LAN (Wi-Fi), Bridging and Virtual Bridged LANs. An individual working group provides the focus for each area.
IEEE 802
43
A passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. It typically consists of an insulated wire wound into a coil around a core.
When the current flowing through this changes, the time-varying magnetic field induces an electromotive force (e.m.f.) (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, these oppose any changes in current through them.
Inductor (also called a coil, choke, or reactor)
44
In physics, ___ is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive ___ result from the interaction of waves that are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency. ___ effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves, gravity waves, or matter waves.
Interference
45
The ___ is a unit of energy equal to 3.6 megajoules. If energy is transmitted or used at a constant rate (power) over a period of time, the total energy in ___ is equal to the power in kilowatts multiplied by the time in hours. The ___ is commonly used as a billing unit for energy delivered to consumers by electric utilities.
Kilowatt hour (symbol: kW⋅h or kW h; commonly but incorrectly symbolized as kWh)
46
In electronics, a ___ is an idealized or physical device implementing a Boolean function; that is, it performs a logical operation on one or more binary inputs and produces a single binary output. Depending on the context, the term may refer to an ideal ___, one that has for instance zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device.
___ are primarily implemented using diodes or transistors acting as electronic switches, but can also be constructed using vacuum tubes, electromagnetic relays (relay logic), fluidic logic, pneumatic logic, optics, molecules, or even mechanical elements. With amplification, ___ can be cascaded in the same way that Boolean functions can be composed, allowing the construction of a physical model of all of Boolean logic, and therefore, all of the algorithms and mathematics that can be described with Boolean logic.
Logic gate
47
A patented digital wireless data communication technology developed by Cycleo of Grenoble, France, and acquired by Semtech in 2012.
Achieves its extremely long range connectivity, possible 100km+, by trading off data rate. Because its data rates are below 50kbps and because ___ is limited by duty cycle and other restrictions, it is suitable in practice for non-real time applications in which one can tolerate delays.
Is a spread spectrum modulation technique derived from chirp spread spectrum (CSS) technology, and is the first low-cost implementation of chirp spread spectrum for commercial usage.
LoRa (Long Range)
48
A ___ is a vector field that describes the magnetic influence of electric charges in relative motion and magnetized materials. The effects of ___ are commonly seen in permanent magnets, which pull on magnetic materials (such as iron) and attract or repel other magnets. ___ surround and are created by magnetized material and by moving electric charges (electric currents) such as those used in electromagnets. They exert forces on nearby moving electrical charges and torques on nearby magnets. In addition, a ___ that varies with location exerts a force on magnetic materials. Both the strength and direction of a ___ vary with location. As such, it is described mathematically as a vector field.
Magnetic field
49
In telecommunication and data storage, ___ is a line code in which the encoding of each data bit is either low then high, or high then low, for equal time. It is a self-clocking signal with no DC component. As a result, electrical connections using a ___ are easily galvanically isolated.
Manchester code (also known as phase encoding, or PE)
50
A ___ of a device is a unique identifier assigned to a network interface controller (NIC). For communications within a network segment, it is used as a network address for most IEEE 802 network technologies, including Ethernet, Wi-Fi, and Bluetooth. Within the Open Systems Interconnection (OSI) model, ___ are used in the medium access control protocol sublayer of the data link layer. As typically represented, ___ are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or no separator.
Media Access Control address (MAC address)
51
A small, relatively inexpensive computer with a microprocessor as its central processing unit (CPU). It includes a microprocessor, memory, and minimal input/output (I/O) circuitry mounted on a single printed circuit board.
Microcomputer (MCU)
52
A computer processor that incorporates the functions of a central processing unit on a single integrated circuit (IC), or at most a few integrated circuits
Microprocessor
53
A ___ is a computer bus in which all components are connected to the electrical circuit. A process of arbitration determines which device sends information at any point. The other devices listen for the data they are intended to receive.
___ have the advantage of simplicity and extensibility, but their differing electrical characteristics make them relatively unsuitable for high frequency or high bandwidth applications.
Multidrop bus (MDB)
54
In radio, ___, is a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation.
Multiple-input and multiple-output, or MIMO
55
In electronics, a ___, is a device that selects between several analog or digital input signals and forwards it to a single output line. A ___ of 2 to the power of n inputs has n select lines, which are used to select which input line to send to the output. ___ are mainly used to increase the amount of data that can be sent over the network within a certain amount of time and bandwidth. ___ can also be used to implement Boolean functions of multiple variables.
Multiplexer (or mux), also known as a data selector
56
A flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. These are used most often as a means to transmit light between the two ends of the fiber and find wide usage in communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss; in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer excessively.
Optical fiber
57
___ is the rate of Energy transfer.
___ = Voltage x Current
___ = (Joule / Coulomb) * (Coulomb/Second)
___ = Joule per Second
Power (W - watt)
58
Mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate.
Components are generally soldered onto this to both electrically connect and mechanically fasten them to it.
Printed circuit board (PCB)
59
A quickly accessible location available to a computer's central processing unit (CPU).
This usually consist of a small amount of fast storage, although some ___ have specific hardware functions, and may be read-only or write-only.
Processor Register
60
___ is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a ___ stream, the amplitude of the analog signal is sampled regularly at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps.
Pulse-code modulation (PCM)
61
In physics, ___ is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:
- electromagnetic ____, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma ___ (γ)
- particle ___, such as alpha ___ (α), beta ___ (β), and neutron ___ (particles of non-zero rest energy)
- acoustic ___, such as ultrasound, sound, and seismic waves (dependent on a physical transmission medium)
- gravitational ___, ___ that takes the form of gravitational waves, or ripples in the curvature of spacetime.
Radiation
62
___ is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A ___ device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.
___ contains multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and ___ devices often have multiple data lines and are said to be "8-bit" or "16-bit", etc. devices.
Random-access memory (RAM)
63
___ is a type of non-volatile memory used in computers and other electronic devices. Data stored in ___ cannot be electronically modified after the manufacture of the memory device. ___ is useful for storing software that is rarely changed during the life of the system, sometimes known as firmware. Software applications for programmable devices can be distributed as plug-in cartridges containing ___.
Read-only memory (ROM)
64
In electronics, when describing a voltage or current step function, ___ is the time taken by a signal to change from a specified low value to a specified high value. These values may be expressed as ratios or, equivalently, as percentages with respect to a given reference value. In analog electronics or digital electronics, these percentages are commonly the 10% and 90% (or equivalently 0.1 and 0.9) of the output step height: however, other values are commonly used.
Rise time
65
A material has an electrical conductivity value falling between that of a metal, like copper, gold, etc. and an insulator, such as glass. Their resistance decreases as their temperature increases, which is behaviour opposite to that of a metal.
Semiconductor
66
In telecommunication and data transmission, this communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.
Serial communication
67
Systems that do not need the duplex capability may instead use ___ communication, in which one device transmits and the others can only "listen". Examples are broadcast radio and television, garage door openers, baby monitors, wireless microphones, and surveillance cameras. In these devices the communication is only in one direction.
Simplex system
68
In telecommunication and radio communication, ___ techniques are methods by which a signal (e.g., an electrical, electromagnetic, or acoustic signal) generated with a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. These techniques are used for a variety of reasons, including the establishment of secure communications, increasing resistance to natural interference, noise, and jamming, to prevent detection, to limit power flux density (e.g., in satellite down links), and to enable multiple-access communications.
Spread spectrum
69
Refers to the frequency at which a chip like a central processing unit (CPU), one core of a multi-core processor, is running and is used as an indicator of the processor's speed. It is measured in clock cycles per second or its equivalent, the SI unit hertz (Hz)
The clock rate
70
The basic operational process of a computer system.
This cycle is repeated continuously by a computer's central processing unit (CPU), from boot-up until the computer has shut down.
The instruction cycle (also known as the fetch-decode-execute cycle or the fetch-execute cycle)
71
A ___ is a passive electrical device that transfers electrical energy between two or more circuits. A varying current in one coil of the ___ produces a varying magnetic flux, which, in turn, induces a varying electromotive force across a second coil wound around the same core. Electrical energy can be transferred between the two coils, without a metallic connection between the two circuits. Faraday's law of induction discovered in 1831 described the induced voltage effect in any coil due to changing magnetic flux encircled by the coil.
___ are used for increasing or decreasing the alternating voltages in electric power applications, and for coupling the stages of signal processing circuits.
Transformer
72
A semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the ___'s terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a ___ can amplify a signal. Today, some ___ are packaged individually, but many more are found embedded in integrated circuits.
Transistor
73
A ___ system consists of a host with one or more downstream ports, and multiple peripherals, forming a tiered-star topology. Additional ___ hubs may be included, allowing up to five tiers. A ___ host may have multiple controllers, each with one or more ports. Up to 127 devices may be connected to a single host controller. ___ devices are linked in series through hubs. The hub built into the host controller is called the root hub.
A ___ device may consist of several logical sub-devices that are referred to as device functions. A composite device may provide several functions, for example, a webcam (video device function) with a built-in microphone (audio device function). An alternative to this is a compound device, in which the host assigns each logical device a distinct address and all logical devices connect to a built-in hub that connects to the physical ___ cable.
___ device communication is based on pipes (logical channels). A pipe is a connection from the host controller to a logical entity within a device, called an endpoint. Because pipes correspond to endpoints, the terms are sometimes used interchangeably. Each ___ device can have up to 32 endpoints (16 in and 16 out), though it is rare to have so many. Endpoints are defined and numbered by the device during initialization (the period after physical connection called "enumeration") and so are relatively permanent, whereas pipes may be opened and closed.
USB
74
___ is the Electric Potential.
___ = Energy /Charge
___ = Joule (Energy) per Coulomb (Electric Charge)
Voltage (V - Volts)
75
A measurement of wire diameter. This determines the amount of electric current a wire can safely carry, as well as its electrical resistance and weight.
Wire gauge
76
An ___ allows a data stream to be broken into multiple lower data rate communication links. An ___ differs from a demultiplexer because the multiple output streams from the former stay inter-related, whereas those from the latter are unrelated. An ___ is the opposite of a multiplexer in that it divides one high-speed link into multiple low-speed links, whereas a multiplexer combines multiple low-speed links into one high-speed link.
Inverse multiplexer (often abbreviated to inverse MUX or IMUX)
77
Is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. In ___ modulation, the ___ (signal strength) of the carrier wave is varied in proportion to that of the message signal being transmitted. The message signal is, for example, a function of the sound to be reproduced by a loudspeaker, or the light intensity of pixels of a television screen.
Amplitude modulation (AM)
78
___ is a type of non-volatile memory used in computers, integrated in microcontrollers for smart cards and remote keyless systems, and other electronic devices to store relatively small amounts of data but allowing individual bytes to be erased and reprogrammed.
___ are organized as arrays of floating-gate transistors. ___ can be programmed and erased in-circuit, by applying special programming signals. Originally, ___ were limited to single byte operations, which made them slower, but modern ___ allow multi-byte page operations. An ___ has a limited life for erasing and reprogramming, now reaching a million operations in modern ___. In an ___ that is frequently reprogrammed, the life of the ___ is an important design consideration.
Electrically erasable programmable read-only memory (EEPROM, also E2PROM)
79
___ is a type of random access semiconductor memory that stores each bit of data in a memory cell consisting of a tiny capacitor and a transistor, both typically based on metal-oxide-semiconductor (MOS) technology. The capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. The electric charge on the capacitors slowly leaks off, so without intervention the data on the chip would soon be lost. To prevent this, ___ requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of ___, in contrast to static random-access memory (SRAM) which does not require data to be refreshed. Unlike flash memory, ___ is volatile memory (vs. non-volatile memory), since it loses its data quickly when power is removed. However, ___ does exhibit limited data remanence.
Dynamic random-access memory (DRAM)
80
___ is a type of semiconductor random-access memory (RAM) that uses bistable latching circuitry (flip-flop) to store each bit. ___ exhibits data remanence, but it is still volatile in the conventional sense that data is eventually lost when the memory is not powered.
The term ___ differentiates ___ from DRAM (dynamic random-access memory) which must be periodically refreshed. ___ is faster and more expensive than DRAM; it is typically used for CPU cache while DRAM is used for a computer's main memory.
Static random-access memory (static RAM or SRAM)
81
A ___ is a computer processor integrated circuit with two or more separate processing units, called ___, each of which reads and executes program instructions, as if the computer had several processors. The instructions are ordinary CPU instructions (such as add, move data, and branch) but the single processor can run instructions on separate ___ at the same time, increasing overall speed for programs that support multithreading or other parallel computing techniques. Manufacturers typically integrate the ___ onto a single integrated circuit die (known as a chip multiprocessor or CMP) or onto multiple dies in a single chip package.
Multi-core processor (with cores)
82
___ is for when you run out of physical memory, you use virtual memory, which stores the data in memory on disk. Reading from disk is several orders of magnitude slower than reading from memory, so this slows everything way down. (Exchanging data between real memory and virtual memory is "___". The space on disk is "___ space".)
Swap memory
83
A ___ is a material or object that produces a ___ field. This ___ field is invisible but is responsible for the most notable property of a ___: a force that pulls on other ferro___ materials, such as iron, and attracts or repels other magnets.
A permanent ___ is an object made from a material that is ___ and creates its own persistent ___ field. An everyday example is a refrigerator ___ used to hold notes on a refrigerator door. Materials that can be ___, which are also the ones that are strongly attracted to a ___, are called ferro___ (or ferri___). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferro___ (and ferri___) materials are the only ones attracted to a ___ strongly enough to be commonly considered ___, all other substances respond weakly to a ___ field, by one of several other types of ___.
Magnet
84
An ___ is a combinational digital electronic circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on floating point numbers. An ___ is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs). A single CPU, FPU or GPU may contain multiple ___.
The inputs to an ___ are the data to be operated on, called operands, and a code indicating the operation to be performed; the ___ output is the result of the performed operation. In many designs, the ___ also has status inputs or outputs, or both, which convey information about a previous operation or the current operation, respectively, between the ___ and external status registers.
Arithmetic logic unit (ALU)
85
A ___ is a part of a computer system specially designed to carry out operations on floating-point numbers. Typical operations are addition, subtraction, multiplication, division, and square root. Some ___ can also perform various transcendental functions such as exponential or trigonometric calculations, but the accuracy can be very low, so that some systems prefer to compute these functions in software.
In general-purpose computer architectures, one or more ___ may be integrated as execution units within the central processing unit; however, many embedded processors do not have hardware support for floating-point operations (while they increasingly have them as standard, at least 32-bit ones).
Floating-point unit (FPU, colloquially a math coprocessor)
86
A ___ is a specialized electronic circuit designed to rapidly manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. ___ are used in embedded systems, mobile phones, personal computers, workstations, and game consoles. Modern ___ are very efficient at manipulating computer graphics and image processing. Their highly parallel structure makes them more efficient than general-purpose central processing units (CPUs) for algorithms that process large blocks of data in parallel. In a personal computer, a ___ can be present on a video card or embedded on the motherboard. In certain CPUs, they are embedded on the CPU die.
Graphics processing unit (GPU)
87
In computer networking, ___ refers to a method of statistically multiplexing small fixed-length packets, called "___", to transport data between computers or kinds of network equipment. It is an unreliable, connection-oriented packet switched data communications protocol.
Cell relay
88
A ___ is an electro-mechanical data storage device that uses magnetic storage to store and retrieve digital data using one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. ___ are a type of non-volatile storage, retaining stored data even when powered off.
Hard disk drive (HDD), hard disk, hard drive, or fixed disk
89
In computing, an ___ is a flat, usually circular disc which encodes binary data (bits) in the form of pits (binary value of 0 or off, due to lack of reflection when read) and lands (binary value of 1 or on, due to a reflection when read) on a special material (often aluminium) on one of its flat surfaces. The encoding material sits atop a thicker substrate (usually polycarbonate) which makes up the bulk of the disc and forms a dust defocusing layer. The encoding pattern follows a continuous, spiral path covering the entire disc surface and extending from the innermost track to the outermost track
Optical disc (OD)
90
A ___ is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. ___ lack the physical spinning disks and movable read-write heads used in hard drives ("HDD") or floppy disks.
Solid-state drive or solid-state disk (SSD)
91
A ___ is the fraction of one period in which a signal or system is active. ___ is commonly expressed as a percentage or a ratio. A period is the time it takes for a signal to complete an on-and-off cycle.
Duty cycle or power cycle
92
An ___ is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material that is normally silicon. The integration of large numbers of tiny MOS transistors into a small chip results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components.
Integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip)
93
The ___ is a type of insulated-gate field-effect transistor that is fabricated by the controlled oxidation of a semiconductor, typically silicon. The voltage of the covered gate determines the electrical conductivity of the device; this ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals.
Metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also known as the metal–oxide–silicon transistor (MOS transistor, or MOS)
94
___ is a logic gate that gives a true (1 or HIGH) output when the number of true inputs is odd.
XOR gate (sometimes EOR, or EXOR and pronounced as Exclusive OR)
95
The ___ is a basic digital logic gate that implements logical conjunction. A HIGH output (1) results only if all the inputs to the AND gate are HIGH (1). If none or not all inputs to the AND gate are HIGH, LOW output results.
AND gate
96
The ___ is a digital logic gate that implements logical disjunction. A HIGH output (1) results if one or both the inputs to the gate are HIGH (1). If neither input is high, a LOW output (0) results.
OR gate
97
___ is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of an AND gate. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1) output results.
NAND gate (NOT-AND)
98
___ is a logic gate that is complement to that of an OR gate. A HIGH output (1) results if both the inputs to the gate are LOW (0); if one or both input is HIGH (1), a LOW output (0) results.
NOR gate
99
___ is a logic gate whose function is the logical complement of the exclusive OR (XOR) gate. A high output (1) results if both of the inputs to the gate are the same. If one but not both inputs are high (1), a low output (0) results.
XNOR gate (sometimes ENOR, EXNOR or NXOR and pronounced as Exclusive NOR), sometimes called an "equivalence gate"
100
___ is a method of transmitting radio signals by rapidly changing the carrier frequency among many distinct frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver. ___ is used to avoid interference, to prevent eavesdropping, and to enable code-division multiple access (CDMA) communications.
Frequency-hopping spread spectrum (FHSS)
101
The ___ is a relative unit of measurement. It is used to express the ratio of one value of a power or field quantity to another, on a logarithmic scale, the logarithmic quantity being called the power level or field level, respectively. Two signals whose levels differ by one ___ have a power ratio of 101/10 (approximately 1.25893) and an amplitude (field quantity) ratio of 101⁄20 (1.12202).
It can be used to express a change in value (e.g., +1 ___ or −1 ___) or an absolute value. In the latter case, it expresses the ratio of a value to a fixed reference value; when used in this way, a suffix that indicates the reference value is often appended to the ___ symbol. For example, if the reference value is 1 volt, then the suffix is "V" (e.g., "20 ___V"), and if the reference value is one milliwatt, then the suffix is "m" (e.g., "20 ___m").
Decibel (symbol: dB), one tenth of a bel (B)
102
___ studies the quantification, storage, and communication of information. It was originally proposed by Claude Shannon in 1948 to find fundamental limits on signal processing and communication operations such as data compression, in a landmark paper titled "A Mathematical Theory of Communication".
Information theory
103
In information theory, the ___, establishes that for any given degree of noise contamination of a communication channel, it is possible to communicate discrete data (digital information) nearly error-free up to a computable maximum rate through the channel.
The ___ of a communication channel refers to the maximum rate of error-free data that can theoretically be transferred over the channel if the link is subject to random data transmission errors, for a particular noise level.
Noisy-channel coding theorem (sometimes Shannon's theorem or Shannon's limit). Shannon limit or Shannon capacity.
104
In information theory, the ___ of a random variable is the average level of "information", "surprise", or "uncertainty" inherent in the variable's possible outcomes. The concept of information ___ was introduced by Claude Shannon in his 1948 paper "A Mathematical Theory of Communication". As an example, consider a biased coin with probability p of landing on heads and probability 1-p of landing on tails. The maximum surprise is for p = 1/2, when there is no reason to expect one outcome over another, and in this case a coin flip has an ___ of one bit. The minimum surprise is when p = 0 or p = 1, when the event is known and the ___ is zero bits. Other values of p give different ___ between zero and one bits.
Entropy
