Technical Glossary - CNX Software

Throughout all articles in this blog, I use a lot of technical terms and acronyms that you may not be familiar with. This glossary will include technical terms used in Android and Linux devices, development boards, and embedded platforms. If one or more relevant terms or acronyms is/are missing, please let me know in the comment section or via the contact form.

0-9 – A – B – C – D – E – F – G – H – I – J – K – L – M – N – O – P – Q – R – S – T – U – V – W – X – Y – Z

0-9

1-Wire – A single-wire (plus ground) communications protocol used for memory products, interface solutions, and by SW tools.
10GbE – 10-Gigabit Ethernet
10Base2 – So-called Thin Ethernet, using RG-58 coax cables and BNC connectors to construct a chain of cables, which must be terminated by resistors; supports a maximum (theoretical) transmission of 10 Mbit/s.
10Base5 – The older Thick Ethernet, which used vampire taps into a single cable; supports a maximum (theoretical) transmission of 10 Mbit/s.
10BaseT – Ethernet over UTP cables, using hubs to produce a star topology; supports a maximum (theoretical) transmission of 10 Mbit/s.
100BaseT – Ethernet over UTP cables, using hubs to produce a star topology; supports a maximum (theoretical) transmission of 100 Mbit/s.
1000BaseT – Ethernet over UTP cables, using hubs to produce a star topology; supports a maximum (theoretical) transmission of 1Gbit/s.
3G – Third-generation mobile telephone protocols that support higher data rates, for non-voice communications such as multimedia and Internet access.
3GPP – Third Generation Partnership Project, a collaboration of cell phone technology standards bodies.
802.11 IEEE – Standard that specifies medium-access and physical-layer specifications for 1Mbps and 2Mbps wireless connectivity between fixed, portable, and moving stations within a local area.
802.11a – IEEE standard that governs the deployment of 5GHz OFDM systems. It specifies the implementation of the physical layer for wireless UNII b.
802.11b – An international IEEE standard for WLAN networks (Wi-Fi), operating at 2.4GHz and providing a maximum data transfer rate of 11Mbps.
802.11g – Wi-Fi operating at 2.4 GHz
802.11n – Wi-Fi operating at 2.4 or 5 GHz (optional) at a maximum data transfer rate of 600 MBps (Typical 150 Mbps or 300 Mbps)
802.11ac – Wi-Fi operating at 5 GHz at a maximum data transfer rate of 433.3 Mbps per spatial stream, 1300 Mbit/s total
802.11af – Wi-Fi operating at 900 MHz between 150 Kbit/s and 40 Mbit/s for the Internet of things.

A

A-Weighting – standard weighting curve applied to audio measurements, designed to reflect the response of the human ear. Unit of measure: “dBA,” or A-weighted dB levels.
A/D Converter – Analog to digital converter, a circuit that converts analog signals into a stream of digital data.
AC – Alternating current, a signal or power source that varies with time, switching polarities. Typically, sinusodial and constant frequency.
Accelerometer – A sensor or transducer for measuring acceleration.
ACPI – Advanced Configuration and Power Interface: An industry-standard specification for operating-system-directed power management for laptop, desktop, and server computers.
ADPCM – Adaptive Differential Pulse Code Modulation: A compression technique that encodes only the difference between sequential samples.
ADSL – Asymmetric Digital Subscriber Line: A method for moving data over regular phone lines. An ADSL circuit carries much more data than a modem can encode on a regular phone connection. ADSL rides on the regular phone wires coming into the subscriber’s premises (twisted pair copper).
AFE – Analog Front End: The analog portion of a circuit which precedes A/D conversion.
AGC – Automatic Gain Control: A circuit that modulates an amplifier’s gain, in response to the relative strength of the input signal, in order to maintain the output power.
Ah – Ampere-hour(s): A measure of battery capacity. A 4Ah battery could, for instance, deliver 1A for 4 hours, 1/2A for 8 hours, etc.
Air Discharge – Method for testing ESD-protection structures in which the ESD generator is discharged through an air gap between the generator and the device under test (DUT).
AIS – Alarm indication system. Also a telecom company in Thailand.
AISG – The Antenna Interface Standards Group (AISG) creates open specifications for antenna-line control and monitoring for 3G systems.
Alternator – An electromechanical device that converts mechanical power into AC electrical power.
AM – Amplitude Modulation: A modulation method in which the carrier amplitude changes with the input signal amplitude.
Ambient Temperature – Temperature of the air surrounding a component.
Ambient Temperature Sensor – Temperature sensor used to measure the temperature of the air that surrounds a component (the ambient temperature).
AMLCD – Active-matrix liquid-crystal display
AMOLED – Active-matrix organic light-emitting diode. Display technology for use in mobile devices and televisions.
Amp – Abbreviation for Ampere, or Amplifier
AMP – Abbreviation for Asymmetric Multiprocessing, the most common software architecture employed in embedded applications.
Ampacity – The amount of current a conductor can carry without exceeding its specified temperature, in amperes.
Ampere – Unit of electrical current. Current is defined as the amount of charge that flows past a give point, per unit of time. The symbol I is used for current in equations and A is the abbreviation for ampere.
Ampere-hour – A measure of charge (or current flow over time). One ampere-hour (or amp-hour or Ah) is a current of one ampere flowing for one hour. The amount of charge transferred in that hour is 3,600 coulombs (ampere-seconds).
Amplifier – Electrical circuit that produces an output that is a replica of the input. The output may be scaled or have increased drive, or it may provide isolation (so changes in output conditions do not affect the input or other outputs). It may perform other transformations (e.g., filtering or logarithmic drive).
Amplifier Class – Amplifier circuit types are divided into “classes” which describe whether the amplifier operates in a linear or switching mode, and any techniques used to restore linearity of output.
AMR – Automatic Meter Reading: A system installed to read a utility meter remotely.
Analog – A system in which an electrical value (usually voltage or current, but sometimes frequency, phase, etc.) represents something in the physical world. By contrast, a digital system handles a signal as a stream of numbers.
Analog Switch – Switching device capable of switching or routing analog signals, based on the level of a digital control signal. Commonly implemented using a “transmission gate,” an analog switch performs a function similar to that of a relay.
Analog Temperature Sensor – Temperature sensor with a continuous analog voltage or current output that is related, usually linearly, to the measured temperature.
AND – Combining two signals so that the output is on if both signals are present. This can be accomplished by an AND logic gate (two inputs, one output which is high if both inputs are).
Android

Robot designed to look and act like a human
Operating system based on the Linux kernel,and currently designed primarily for touchscreen mobile devices such as smartphones and tablets.

ANSI – American National Standards Institute
APC – Automatic Power Control: Feature in laser drivers that uses feedback from the laser to adjust the drive, to keep the laser’s output constant.
APD – Avalanche Photo Diode. A photodiode designed to take advantage of avalanche multiplication of photocurrent to provide gain.
API – Application program interface: A software layer that allows a system to be programmed via a defined set of commands.
APM – Advanced Power Management: Power management standard for computers that provides five power states: Ready, Stand-by, Suspended, Hibernation, Off.
ASCII – American Standard Codes for Information Interchange
ASIC – Application-specific integrated circuit.
Aspect ratio – Ratio between the width and the height of a pixel on a computer display.
Assembler – Program that compiles programs written in assembly language into object code. Also a synonym for Assembly language.
Assembly language – A low-level computer language that can be translated directly to the object code of the computer processor.
ATE – Automatic test equipment; automated test equipment.
ATM – Asynchronous transfer mode
ATX – Advanced Technology eXtended. Motherboard form factor specification developed by Intel in 1995. Also defines the type of power supply.
Auto Shutdown – Feature in RS-232 interface devices which puts the IC into a low-power shutdown mode when no signal is present on the RS-232 bus.
Autoshutdown Plus – Feature in RS-232 interface devices which puts the IC into a low-power shutdown mode when no signal is present on the bus or the transmitter inputs.
Autotransformer – Transformer that uses a common winding for both the primary and secondary windings.
AWG

Arbitrary waveform generator
American Wire Gauge: A measure of wire thickness (which also dictates cross-sectional area, and for a given material, ampacity). Example: 24 AWG wire has a nominal diameter of 0.0201in or 0.511mm. Also called the Brown and Sharpe Wire Gauge.

B

Bel – Measurement of a signal’s power compared to a reference; also, measurement of sound pressure. See the more commonly used term, “decibel,” or, “dB.”
Symbol for magnetic flux density or magnetic field, as in “B-field.”

Bandwidth

Bandwidth (BW) is a range of frequencies, or information, that a circuit can handle or the range of frequencies that a signal contains or occupies.Example: An AM broadcast radio channel in the US has a bandwidth of 10kHz, meaning that it occupies a 10kHz-wide band, such as the frequencies from 760kHz to 770kHz.
The amount of data a digital channel or line can handle, expressed in bits per second (bps), kilobits per second (kbps), baud, or a similar measure.

Base Station – Also written as basestation. Wireless transceiver at a fixed location (e.g. atop a telephone pole) which is part of a wireless communications network, e.g. the cell phone network.

Baseline – The electrical signal from a sensor when no measured variable is present. Often referred to the output at no-load condition.
Bass Boost – Circuitry that boosts the bass response of the amplifier, improving audio reproduction, especially when using inexpensive headphones.
Battery Backup – Feature of microprocessor supervisory circuits and some power supplies to switch between a main power source and a battery.
Battery Freshness Seal – Feature in microprocessor supervisory circuits which disconnects a backup battery from any down-stream circuitry until VCC is applied the first time. This keeps a backup battery from discharging until the first time a board is plugged in and used, and thus preserves the battery life.
Battery Fuel Gauge – Feature or device that measures the accumulated energy added to and removed from a battery, allowing accurate estimates of battery charge level.
Battery Monitor – Feature that monitors the voltage on a battery and indicates when the battery is low. May also include functions such as charging, remaining capacity estimation, safety monitoring, unique ID, temperature measurement, and nonvolatile (NV) parametric storage.
Battery Switchover – Circuit that switches between the higher of a main supply and a backup battery.
BCD – Binary-coded decimal. Representation of a number in which each decimal digit (0-9) is encoded in binary, with four bits per decimal digit.
BER – Bit Error Rate. A measure of the number of erroneous bits which can be expected in a specified number of bits in a serial stream.
BERT – Bit Error Rate (BER) Tester. A piece of test equipment which determines the bit error rate for a device under test (DUT).
BGA – Ball grid array, a packaging technology.
Bidirectional – The device accommodates signals traveling either direction though a single channel.
big.LITTLE Processing – SoC technology by ARM that combines “little” cores for low power tasks, and “big” cores for more demanding tasks, in order to optimize power consumption.
BIOS – Simple, low-level operating system which supplies a uniform API to higher-level operating systems; BIOS is generally implemented in ROM of some sort.
Bipolar Inputs – An input which accommodates signals both above and below ground.
Bipolar Junction Transistor – A Bipolar Junction Transistor, or BJT, is a solid-state device in which the current flow between two terminals (the collector and the emitter) is controlled by the amount of current that flows through a third terminal (the base).
BIST – Built-in self-test.
Bit – Smallest entity of information: can have one of two states (0-1, on-off, open-closed, etc.).
Bit Banging – Technique which uses the general-purpose ports of a microcontroller to emulate a serial interface standard (I2C, SPI, etc).
Bit Error Ratio – Number of erroneous bits divided by the total number of bits transmitted, received, or processed over some stipulated period.
Bitplanes – Number of bits available for each display pixel to code for visual appearance (color, proximity, etc.).
Blade Server – Computer system on a motherboard, which includes processor(s), memory, a network connection, and sometimes storage. The blade idea is intended to address the needs of large-scale computing centers to reduce space requirements for application servers and lower costs.
Blink Control – Controls the display segment blink rate.
Block device – Device that exchanges data with the operating system in sizable blocks (e.g., 512 bytes) at a time.
BoM – Bill of Materials. List of components of an electronics circuit.
BLE – Bluetooth Low Energy. Part of Bluetooth 4.0. Aimed at ultra low power applications running off a coin cell.
Bluetooth – Technology that allows voice and data connections between a wide range of mobile and stationary devices through short-range digital two-way radio. For instance, it specifies how mobile phones, Wireless Information Devices (WIDs), computers and PDAs interconnect with each other, with computers, and with office or home phones.
BLVDS – Bus low-voltage differential signal
BOC – Bit-oriented code
Boost Converter – Power supply that steps an input voltage up (boosts it) to a higher, regulated voltage.
Bootloader – Firmware which exists to load the operating system kernel and begin its functioning.
BPSK – Binary phase-shift keying
BRI – Bit-rate interface
Bridge Battery – Battery intended to provide power to system memory while the main battery is replaced.
Brightness – Brightness is how Luminance (light intensity) is perceived by the human eye.
Broadband – Transmission medium with enough bandwidth to carry multiple voice, video, or data channels simultaneously.
Brownout – Condition where the voltage supplied to the system falls below the specified operating range, but above 0V.
BSC – Basic Spacing between Centers. Term that appears on IC package drawings in reference to dimensions between pins.
BSD – Variant of UNIX originally developed at the University of California, Berkeley.
BTRFS – B-tree file system. GPL copy-on-write file system for Linux developed by Oracle.
BTS – Base Transceiver Station: The stationary component of a cellphone system includes transmit-receive units and one or more antennas.
Buffer – Temporary storage
Burst Mode

Temporary high-speed data-transfer mode that can transfer data at significantly higher rates than would normally be achieved with nonburst technology.
Maximum short-term throughput which a device is capable of transferring data.

C

Capacitance, capacitor
Coulomb
Color portion of a video signal (see “Y/C” definition)

CAD – Computer-aided design
CAN – Controller Area Network. The CAN protocol is an international standard defined by ISO 11898, mostly used in automotive and industrial applications.
Capacitor – Passive electronic component that consists of two conductive plates separated by an insulating dielectric.
Capacitance – Dictates the amount of charge that can be stored at a given voltage. Measured in farad (F)
CardBus – 32-bit version of the PC card (formerly PCMCIA) standard
CAT3 – Category 3. Refers to Ethernet cabling that satisfies the criteria for the EIA/TIA-568 standard’s Category 3, which allows data transfers up to 10Mbps.
CAT5 – Category 5. Refers to Ethernet cabling that satisfies the criteria for the EIA/TIA-568 standard’s Category 5, which allows data transfers up to 100Mbps.
CATV – Originally “Community Antenna Television,” a term which now refers to any community television system distributed by cable.
CBR – Constant bit rate
CCD – Charge Coupled Device. One of the two main types of image sensors used in digital cameras.
CCFL – Cold Cathode Fluorescent Lighting: Often used as a backlight for LCD displays.
CCFT – Cold Cathode Fluorescent Tube: Often used as a backlight for LCD displays.
CDMA – Code Division Multiple Access: A digital cellular technology that uses spread-spectrum techniques.
CE – Control Chip enable control
Charge Pump – Power supply which uses capacitors to store and transfer energy to the output, often stepping the voltage up or down.
Chip

Integrated circuit: A semiconductor device that combines multiple transistors and other components and interconnects on a single piece of semiconductor material.
Encoding element, in Direct-Sequence Spread Spectrum systems.

Chrominance – Color portion portion of a composite video signal.
CIFS – Microsoft’s successor to SMB, a suite of protocols for sharing file and print services (among Windows machines or UN*X machines running CIFS servers like Samba).
CISC – Complex instruction set computer (CISC): Computer hardware designed to support complex instructions, as opposed to RISC (reduced instruction set computer) architecture.
Clock and Data Recovery – The process of extracting and reconstructing clock and data information from a single-wire/channel, serial data stream.
Clock Jitter – Periodic waveform (especially a clock) is expected to cross certain thresholds at precisely timed moments. Variations from this ideal are called jitter.
Clock Throttling – Reducing the frequency or duty-cycling the clock of an integrated circuit usually for the purpose of reducing heat generation.
CMOS – Complementary metal-oxide semiconductor technology in which p- and n-channel MOS transistors are used in tandem.
CNC – Computer numeric control
CODEC – Short for compressor/decompressor, a codec is any technology for compressing and decompressing data. Codecs can be implemented in software, hardware, or a combination of both.
COG – Chip-on-glass
CoM – Computer-on-Module
CompoNet – CompoNet is a four-wire, industrial, bus with a master-slave architecture. Up to 256 slaves are supported on a bus. Data rates of 93.75kbps to 4Mbps and network lengths up to 1500 meters with repeaters are possible.
Contact Discharge – ESD test method where the ESD generator makes direct contact with the device under test (DUT).
Core dump – Content of memory written to a file on disk (usually called “core”) when a program crashes.
Coulomb – Abbreviated C. Standard measure of electrical charge.
CPGA – Ceramic pin grid array, an IC packaging technology.
CRC – Cyclic Redundancy Check: A check value calculated from the data, to catch most transmission errors.
CRT – A cathode ray tube (CRT) is a display device which uses an electron beam to energize a phosphorescent coating.
Cryptanalysis – Art and science of breaking encryption or any form of cryptography.
CS – Chip select
CSP – Chip Scale Package: An IC packaging technology in which solder balls take the place of pins, making the smallest package available.
CUDA – Compute Unified Device Architecture. Parallel computing platform and programming model created by NVIDIA and implemented by their GPUs.

D

D/A Converter – Digital-to-analog converter (DAC). Receives digital data (a stream of numbers) and outputs a voltage or current proportional to the value of the digital data.
Daisy Chain – Method of propagating signals along a bus in which the devices are connected in series and the signal passed from one device to the next.
Data Converter – A/D or D/A converter: An electronic circuit that converts analog signals to digital, or vice-versa.
dB – Decibels: A method for specifying the ratio of two signals.
dBm – Unit that defines a signal level by comparing it to a reference level. The reference level of 0dBm is defined as 1mW. The signal level in dBm is 10 times the log of the signal’s power over that of the 0dBm reference.
DBS – Direct Broadcast Satellite: A system which broadcasts directly from satellite to the subscriber (end user).
DC – Direct current
DC-DC – Any of the family of switch-mode voltage regulators, these devices use an inductor to store and transfer energy to the output in discrete packets, resulting in highly efficient power conversion.
DCE – Data Communication Equipment
DCS – Digital Cellular System: Any cellular phone system that uses digital (e.g. TDMA, GSM, CDMA).
DDR – Memory Double Data Rate Synchronous DRAM. DDR memory reads data on both the rising and falling edge of the clock, achieving a faster data rate.
DDR3 – Double data rate type three synchronous dynamic random access memory.
DDR4 – Double data rate fourth generation synchronous dynamic random-access memory. Higher-speed successor to DDR3, not compatible.
DECT – Digital European cordless telephone
Digital Signal Processor – A Digital Signal Processor, or DSP, is a special-purpose digital circuit that acts on digitized signals, such as audio.
DIO – Data input/output
Diode – A two-terminal device that rectifies signals (passes current in only one direction).
DIP – Dual Inline Package. Integrated circuit package with two rows of pins. Easy to solder. Also see PDIP: Plastic Dual Inline Package. DIP package with a molded plastic body, and CDIP – Ceramic Dual Inline Package. DIP package with a ceramic body.
DisplayPort – Digital display interface developed by the Video Electronics Standards Association (VESA). VESA designed it to replace VGA, DVI, and FPD-Link.
DHCP – Provides for automatic downloading of IP address and other configuration data from a server to a client. Allows for reuse of IP addresses so that the number of hosts can exceed the number of available IP addresses. See RFC2131.
Distribution – Collection of software needed to operate a computer including the Linux kernel and various utilities and applications.
DMA – Direct Memory Access. A scheme which reads or writes data directly to memory, bypassing the processor and the processor bus.
DMM – Digital Multimeter.
DMR – Digital microwave radio
DOCSIS – Data Over Cable Service Interface Specification: A standard for delivering data over cable TV systems, typically for subscriber Internet access services.
DQPSK – Differential quadrature phase-shift keying
DRAM – Dynamic RAM. Random-Access Memory that uses a continuous clock. Unlike SRAM, when DRAM is no longer clocked, its data is lost.
DSDA – Dual SIM Dual Active
DSL – Mechanism for providing high-speed digital communications (e.g. Internet access) over a standard phone line.
DSLAM – Digital Subscriber Line Access Multiplexer: a device which takes a number of ADSL subscriber lines and concentrates these to a single ATM line.
DSSP – Digital-sensor signal processor
DSSS – Direct-Sequence Spread Spectrum. Transmission technology used in WLAN (wireless LAN) transmissions where a data signal at the sending station is combined with a higher data-rate bit sequence, or chipping code, that divides the user data according to a spreading ratio.
DTB – Digital terrestrial broadcasting
DTE – Data terminal equipment; interchangeable with DCE
DTMF – Dual Tone Multiple Frequency (DTMF)
DVB – Digital Video Broadcast
DVI – Digital Video Interface

E

E1 – Wide-area, digital transmission scheme, used predominantly in Europe, that carries data at a rate of 2.048Mbps. E1 lines can be leased for private use from common carriers.
E2 – Line that carries four multiplexed E1 signals with a data rate of 8.448Mbps.
E3 – Wide-area, digital transmission scheme used predominantly in Europe that carries data at a rate of 34.368Mbps. E3 lines can be leased for private use from common carriers.
eCAP – Enhanced CAPture modules s used in systems where accurate timing of external events is important. This is used in Texas Instruments MCUs and SoCs.
eCSPI – Enhanced Configurable Serial Peripheral Interface
ECU – Engine Control Unit
EDGE – Enhanced Data Rates for GSM Evolution. Enhanced modulation technique designed to increase network capacity and data rates in GSM networks, up to 384Kbps.
EDM – Embedded Design Modules. Open hardware and software standard for x86 and ARM computers on module.
EDMA – Enhanced Direct Memory Access
EEPROM – Electrically erasable programmable read-only memory
Embedded System – System in which the computer (generally a microcontroller or microprocessor) is included as an integral part of the system.
EMC – Electromagnetic Compatibility. Device follows standards such as FCC, CE ,CCC
EMI – Electromagnetic Interference. Unwanted noise from electromagnetic radiation.
eMMC – Embedded MultiMediaCard
Energy Harvesting – Also known as power harvesting or energy scavenging. Process in which energy is captured from a system’s environment and converted into usable electric power. Use in batterless system, or environments with no power sources.
EPROM – Erasable programmable read-only memory
eQDP – Enhanced Quadrature Encoder Pulse modules are primarily intended to get position, direction, and speed information from rotating machines for high performance motioncontrol applications, and appear to be found only in Texas Instruments SoCs and DSPs.
ErP – Energy related Product – Product which do not use energy but have an impact on energy as defined in the EU’s Ecodesign Directive to improve the environmental performance of products.
ESD – Electrostatic Discharge. Release of stored static electricity.
EuP – Energy using Product.
EV

Electric Vehicle.
Evaluation, as in “EV Kit.”

Evaluation Kit – Also known as EV Kit or development kit. A printed circuit board with an integrated circuit and support components to produce a working circuit for evaluation and development. Most Evaluation Kits are fully assembled and tested.
exFAT – Extended File Allocation Table. Microsoft proprietary and patented file system optimized for flash drives.

F

Farad(s): Unit of capacitance.
f in lower case is the standard abbreviation for femto, a metric prefix for 10 to the -15.
Fahrenheit temperature scale.

F2FS – Flash-Friendly File System. File system designed by Samsung for mobile flash storages.
Fail-Safe – Technique used in RS-485 interface transceivers which forces the output to a predefined state in the event of a line short or open circuit.
Fan Controller

Linear – Integrated circuit that varies the speed and airflow of a cooling fan using a variable voltage in response to temperature or system commands.
PWM – Integrated circuit that varies the speed and airflow of a cooling fan using a pulse-width-modulated (PWM) voltage in response to temperature or system commands.

FAT – Simple file system using a table to index files on a block device. It comes in the varieties of FAT-12, FAT-16 and “FAT-32” (aka VFAT), each version supporting various max number of files and partition size.
Fault Tolerant – Will tolerate excessive voltage during a fault condition.
FDD – Frequency-division duplex
FDDI – Fiber Distributed Data Interface. Standard for transmitting data on optical fiber cables at a rate of around 100 Mbps.FDM – Frequency-division multiplexing. Method for carrying multiple channels of information on one channel by dividing the available bandwidth among the channels.
FEC – Forward Error Correction. Technique for detecting and correcting errors from imperfect transmission by adding a small number of extra bits.
Femto Base Station – A femto base station (also called an Access Point Base Station, femtocell, femtobasestation or femto basestation) is an in-home base station.
FET – Field-Effect Transistor. Transistor in which the voltage on one terminal (the gate) creates a field that allows or disallows conduction between the other two terminals (the source and drain). Three types: JFET (Junction Field-Effect Transistor), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and MESFET (Metal-Semiconductor Field-Effect Transistor).
FFT – Fast Fourier Transform
FHSS – Frequency Hopping Spread Spectrum. Transmission technology in which the data signal is modulated by a narrowband carrier signal which changes frequency (“hops”) over a wide band of frequencies.
Fibre Channel – Gigabit interconnect technology that allows concurrent communications among workstations, mainframes, servers, data storage systems, and other peripherals using SCSI and IP protocols.
FIFO – First-In First Out.
FireWire – IEEE 1394 serial interface standard: A high-speed interface between computers and peripherals such as external disk drives, cameras, and camcorders. Trademarked by Apple.
Floating-point – Used with numbers that may represent a fraction. As opposed to integer
FM – Frequency Modulation: A modulation method in which the carrier frequency changes with the input signal amplitude.
FPGA – Field Programmable Gate Array. General-purpose logic devices that can be configured by the end user to perform many, different, complex logic functions.
FSF – Free Software Foundation: a tax-exempt charity that raises funds for work on the GNU project.
FSK – Frequency Shift Keying: A method of transmitting digital data by shifting the frequency of a carrier signal to represent binary 1s and 0s.
FTTB – Fiber-to-the-business
FTTH – Fiber-to-the-home: A method for broadband data (voice, Internet, multimedia, etc.) delivery to the home via optical fiber.
FTP – A protocol for transferring files over the Internet and the software to accomplish the transfer. See RFC959.
Full Duplex – A channel providing simultaneous transmission in both directions.
FVP – Fixed Virtual Platform (ARM model)

G

G – Gram
GaAs – Gallium arsenide: A semiconductor material used for optoelectronic products such as LEDs, and for high-speed electronic devices.
GaAsFET – Gallium arsenide field-effect transistor
GaAsP – Gallium Arsenide Phosphide (or, Gallium Arsenic Phosphide): A semiconductor material used for optoelectronics, including LEDs and photodiodes.
Gain – Amount of amplification accomplished by an amplifier circuit.
Gain Error – Indicates how well the slope of an actual transfer function matches the slope of the ideal transfer function.
Galvanic Isolation – Design technique that separates electrical circuits to eliminate stray currents.
Gamma Correction – Application of a function that transforms brightness or luminance values.
Gate

Controlling terminal of a FET.
Basic logic element (e.g. AND, OR, NOT, NAND, NOR, XOR, etc.).

Gateway – A device or relay mechanism that connects two or more computer networks and which directs packets between the networks.
GbE – Gigabit Ethernet
GBIC – Gigabit Interface Converter: A removable transceiver module permitting Fibre-Channel and Gigabit-Ethernet physical-layer transport.Generator – Electromechanical device that converts mechanical power into electrical power.
GFSK – Gaussian frequency-shift keying. FSK modulation which uses a Gaussian filter to shape the pulses before they are modulated.
GHz – Gigahertz
Gigabit – 1 billion bits.
GLONASS – The Russian Global Navigation Satellite System
GMSK – Gaussian minimum shift keying. Frequency shift keying (FSK) used in GSM systems.
GPIB – General Purpose Interface Bus.
GPIO – General Purpose Input/Output.
GPL – A license for distribution of free software which permits copying, modification and redistribution. It was created by the Free Software Foundation for its projects like GNU, and has been applied to Linux as well.
GPRS – General Packet Radio Service. Radio technology for GSM networks that adds packet-switching protocols and shorter set-up time for ISP connections.
GPS – Global Positioning System.
GPU – Graphics Processing Unit. Blocks that handles 2D and/or 3D graphics, and in some cases video decoding, in an SoC
GRUB – GRand Unified Bootloader. Program that loads the kernel so Linux can boot; can also boot other operating systems.
GSM – Global System for Mobile Communications.
GUI – Graphical user interface

H

H – Henry. Unit of inductance.
Half-Duplex – Data transmission over a circuit capable of transmitting in either direction, but not simultaneously.
HB LED – High-Brightness LED. LEDs bright enough for illumination applications in the car, at home…
HDLC – High Level Data Link Control
HDMI – High-Definition Multimedia Interface. Compact audio/video interface for transferring uncompressed video data and compressed/uncompressed digital audio data from a HDMI-compliant device (“the source device”) to a compatible computer monitor, video projector, digital television, or digital audio device
HDQ – Harmonic Differential Quadrature. One-wire communication interfaces, used for example in Texas Instruments AM437x
HDSL – High bit-rate Digital Subscriber Line
HDTV – High-definition television.
Heat Sink – Mechanical device that is thermally-connected to a heat-producing electronic component, designed to conduct heat away from the device.
HEVC – High Efficiency Video Coding. Video compression format, a successor to H.264/MPEG-4 AVC (Advanced Video Coding), that was jointly developed by the ISO/IEC Moving Picture Experts Group (MPEG) and ITU-T Video Coding Experts Group (VCEG) as ISO/IEC 23008-2 MPEG-H Part 2 and ITU-T H.265. Also known as H.265.
HF – High frequency
HomePlug – Industry-standard method for transmitting data via the power lines. It can transmit audio, video, control signals, etc.
Hot-Swap – Power supply line controller which allows circuit boards or other devices to be removed and replaced while the system remains powered up.
HSDPA – High-Speed Downlink Packet Access. 3G radio interface standard in the HSPA family that increases the datarate and improve the traffic handling of existing UMTS standards.
HSIC – High-Speed Inter-Chip. Industry standard for USB chip-to-chip interconnect with a 2-signal (strobe, data) source synchronous serial interface using 240 MHz DDR signaling to provide only high-speed (480 Mbps data rate).
HSPA – High-Speed Packet Access. Collection of radio interface standards for wireless and cellular handsets or datacards that increase the datarate and improve the traffic handling of existing UMTS standards.
HSSI – High-Speed Serial Interface. Short-distance communications standard for data rates from 2Mbps to 52Mbps.
HSUPA – High-Speed Uplink Packet Access. 3G radio interface standard in the HSPA family that increases the datarate and improve the traffic handling of existing UMTS standards.
HTML – Hyper Text Markup Language. Coding language used to create web pages.
HTML5 – Fifth revision of the HTML standard
HTTP – Hyper Text Transfer Protocol
HVAC – Heating, Ventilation, and Air Conditioning.
Hz – Hertz. Measure of frequency.

I

I²C (I2C) – Pronounced “I-squared-C”. Short for “inter-IC bus”, a two-wire, low-speed, serial data connection IC bus used to run signals between integrated circuits, generally on the same board.
I²S (I2S) – Promounced “I-square-S”. Short for “Inter-IC Sound”, an electrical bus interface standard used for connecting digital audio devices. The I²S bus separates clock and data signals, resulting in a very low-jitter connection. The bus consists of three lines: a clock line, a word-select line, and a multiplexed-data line.
I/O – Input/output
IC

Integrated Circuit.
Internally Connected

ICDI – In-Circuit Debug Interface. Name for USB debug interface found in Texas Instruments MCUs
Impedance – Measure of the opposition to electrical flow. It is measured in ohms.
InGaAs – Indium gallium arsenide
Ingress Protection – Ingress Protection (IP) rating indicates how well an enclosure is protected from penetration by contaminants such as dust or fluids.
Intellectual Property – Creations of the intellect such as trade knowledge, technical information, and literary or artistic work, including patents, copyrights, and trademarks.
Internet Protocol – Standard method for data transfer used on the Internet. Also known as IP or TCP/IP.
IR – Infrared. Light that has a frequency below the visible light spectrum, used for remote controls, line-of-sight wireless data, and night vision applications, among others.
IrDA – Infrared Data Association. Group of device manufacturers that developed a standard for transmitting data via infrared light waves.
ISA – Industry-standard architecture
ISM – Industrial, Scientific and Medical: Radio frequency bands made available for use by communication equipment without license, within certain maximum emitted power limits.
ISO – International Standards Organization.
ISP

Internet Service Provider
Image Signal Processor

ITU – International Telecommunication Union. International organization under the UN that is concerned with telecommunications.

J

JAVA – Programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few implementation dependencies as possible .
JavaScript – Dynamic programming language most commonly used as part of web browsers, but also being used in server-side programming, game development and the creation of desktop and mobile applications. JAVA and JavaScript are completely different languages, and have nothing in common.
JBOD – Just a Bunch of Disks: An array of hard disks without a controller.
JEDEC – Joint Electron Device Engineering Council
Jitter – The slight movement of a transmission signal in time or phase that can introduce errors and loss of synchronization.
Joule – Abbreviated J. Measurement of energy or work.
JPEG

Joint Photography Experts Group
Files compressed using JPEG standard.

JTAG – Joint Test Action Group. Common name for the IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture. Low level debugging port.
JVM – Java virtual machine.

K

K or k

Metric unit representing 1000 or 1024.
Kelvin – Temperature scale. Zero K is defined as absolute zero. 273.15K is 0 degrees C.

kb – Kilobit(s)
Keep-Out Zone – Area on or near a CPU or GPU processor that the circuit board layout design can not use, due to thermal management components, cooling, and mounting constraints.
kg – Kilogram(s)
kHz – Kilohertz
km – Kilometer(s)
KVM

Keyboard Video Mouse. A KVM switch is a switch box used to connect one KVM to multiple computers.
Kernel Virtual Machine. Full virtualization solution on Linux

kW – Kilowatt(s)
kWh – Kilowatt hour(s)

L

L-Band – Group of radio frequencies extending from 390MHz to 1550MHz, e.g. GPS carrier frequencies (1227.6MHz and 1575.42MHz).
LAN – Local Area Network
LCD – Liquid-crystal display
LED – Light-Emitting Diode. A semiconductor device that emits light (usually visible or infrared) when forward-biased.
LIN – Local Interconnect Network. As defined by the LIN-BUS consortium, a LIN is a low data-rate, single-wire communications system, used in automotive and heavy vehicle applications.
Linear

Having the property that the output is proportional to the input.
Analog; as in a “linear” circuit (as opposed to digital).

Lithium batteries – Batteries for low-power, high-reliability, long-life applications such as non-volatile memory and timekeeping (typically in coin-shaped cells). Usually in coin-shape cells.
Lithium-ion batteries – Lithium-ion (Li+, Li-Ion, Lion) cells are generally used as power sources for portable equipment (smartphones, tablet, handheld devices…), and are usually rechargeable.
Lm – Lumen(s)
Lm/W – Lumen(s) per watt
LTE – Long Term Evolution. High-speed mobile communications cellular standard developed by the 3rd Generation Partnership Project (3GPP). LTE is an evolution of GSM/UMTS standards.
LOS Line of sight or, less common, loss of signal
LSB – Least-significant bit.
LSI – Large-scale integration
LT – Landing Team. Linaro team working on specific member hardware such as ARM, Samsung, etc…
Luminance

The emitted light, projected per unit area, measured in cd/m2 (candela per square meter).
The black and white portion of a video signal, also referred to as the “Y” component. A composite, Y/C, or Y/Pb/Pr video signal combines a luminance signal with color components.

LVDS – Low Voltage Differential Signaling

M

M.2 – Specification for internally mounted computer expansion cards and associated connectors. It is intended to replace mSATA. Previsouly known as NGFF
M2M – Machine-to-machine or machine-to-mobile communications, via wireless technologies such as cell phone network technologies, WLAN, Bluetooth, and RFID (radio frequency identification). Applications include automatic meter reading, fleet management, vending, monitoring and control, security and alarms, and telemedicine.
mA – Milliampere, or milliamp: 1/1000 of an Ampere.
MAC Address – Media Access Control Address. 48-bit hardware address that uniquely identifies each node of a IEEE-802 network.
McASP – Multichannel Audio Serial Port used in Texas Instruments SoCs and DSPs.
MCM – Multi-Chip Module. An integrated circuit package that contains two or more interconnected chips.
MCU – Micro-controller Unit
Media Independent Interface (MII) – Parallel digital bus used for 10Mbps and 100Mbps Ethernet.
MegaBaud – RS-232 logic-level compatible data rates that are 1Mbps or higher.
MEMS – Micro Electronic Mechanical Systems. Systems that combine mechanical and electrical components and are fabricated using semiconductor fabrication techniques.
MFSK – Multiple frequency-shift keying
MHz – Megahertz (MHz): Measurement of frequency.
MIMO – Multiple Input, Multiple Output. A MIMO) system has multiple antennas and multiple radios. It takes advantage of multipath effects, where a transmitted signal arrives at the receiver through a number of different paths. Each path can have a different time delay, and the result is that multiple instances of a single transmitted symbol arrive at the receiver at different times.
Mini-ITX – 17 × 17 cm (6.7 × 6.7 in) low-power motherboard form factor.
MMI – Man-machine interface
MoCA – Multimedia over Coax Alliance. Technology that runs over the existing in-home coaxial cabling, enabling whole home distribution of high definition video and content.
MPU – Microprocessing unit
ms – Millisecond(s)
MSB – Most-significant bit.
Msps – Megasamples per second. A measure of speed in digitizing systems, samples per second dictates the maximum frequencies that can be accurately captured.
Multipath – In radio transmission, multipath refers to the simultaneous reception of two copies of the signal, that arrive via separate paths with different delays.
Murphy’s Law – Anything that can go wrong, will.
mV – A millivolt (mV) is 1/1000 of a volt.
mW – Milliwatt(s)
MW – Megawatt(s)

N

nA – Nanoampere(s)
Nanovolt – nV. A billionth of a volt.
NAT – Network address translation
NC – Normally closed (Used in relays)
NDK – Native Development Kit
NF – Noise figure
NFC – Near Field Communication. Short-range high frequency wireless communication technology which enables the exchange of data between devices over about a 10 centimeter distance. Use in mobile phone for mobile payments, data exchange, identification, etc..
NFS – Network File System. A protocol developed by Sun Microsystems that enables a UN*X machine to mount a remote disk area as part of its local filesystem.
NGFF – Next Generation Form Factor. Now called M.2, destined to replace mSATA.
NIC – Network interface card
NiMH – Nickel metal hydride. Rechargeable-battery technology.
NMI – Nonmaskable interrupt
NO – Normally open (Used in relays)
Node.js – Software platform for scalable server-side and networking applications. Node.js applications are written in JavaScript, and non-blocking I/O and asynchronous events. You can also access hardware (e.g. GPIO) via node.js scripts.
Nonvolatile (NV) – NV RAM is memory which retains its stored value when power is removed.
NPR – Noise-power ratio
NRE – Nonrecurring engineering — one-time engineering costs associated with a project.
NRZ – Non Return to Zero.
ns Nanosecond(s)
NTSC – Color television standard established by the National Television Standards Committee in the United States in 1953.
NV-S – Nanovolt seconds
nW – Nanowatt(s)

O

OC – Overcurrent or Overclock
OEM – Original equipment manufacturer
OFC -Open fiber control
OFDM – Orthogonal Frequency Division Multiplexing. A method for multiplexing signals which divides the available bandwidth into a series of frequencies known as tones.
OIS – Optical Image Stabilizer. Mechanism used in a still camera or video camera that stabilizes the recorded image by varying the optical path to the sensor.
OLED – Organic Light-Emitting Diode. An LED made with organic materials.
Open-drain – An open-drain or open-collector output pin is driven by a single transistor, which pulls the pin to only one voltage (generally, to ground).
Operating system – Set of programs that manage the various components and devices of the computer, and its interaction with application programs and users; e.g. Ubuntu, Debian, Windows, MacOS, etc..
Output to Input Ratio – Ratio between the sensed current and the output current of the amplifier.
Overvoltage Protection (OVP) – Circuit that protects downstream circuitry from damage due to excessive voltage.

P

P-P – Peak-to-peak
P2P – Peer-to-peer
pA – Picoampere(s)
PA – Power amplifier. Amplifier used to drive significant power levels.
PAE

Power-added efficiency
Physical Address Extension. Hardware feature require in a 32-bit CPU to access 4 GB RAM. ARM uses LPAE instead.

PAL – Phase alternate line. An (analog) television standard used in most of Europe.
Parallel Interface – Interface that sends data on several wires or wireless channels at once. Opposite is serial interface.
PC / pC

pC – Picocoulomb(s)
PC: Printed circuit (see: Printed Circuit Board)
Personal Computer
Program Counter (Programming)

PCI – Peripheral Component Interconnect. Standard interface used to connect cards and peripheral devices to the processor bus. Hardware include video display cards, network interfaces, etc…
PCI Express – Peripheral Component Interconnect Express, abbreviated as PCIe. Designed to replace the PCI, PCI-X, and AGP standards.
PCM – Pulse-Code Modulation. Conversion of an analog signal (e.g. audio) into digital, binary (0 or 1), coded pulses. Also referred as uncompressed digital audio.
PCMCIA – Personal Computer Memory Card International Association. Standard for miniaturized laptop expansion cards for modems, storage, and other devices. Mostly deprecated.
PDA – Personal digital assistant
pF – Picofarad. A Farad is the unit of capacitance. A pF is 10-12 of a Farad. (1000pF = 1nF, 1000nF = 1 microfarad).
PFM – Pulse-Frequency Modulation: Pulse modulation technique in which the frequency is varied with the input signal amplitude.
PKI – Public Key Infrastructure: A combination of standards, protocols, and software that creates, edits, and revokes digital public key certificates.
PLA – Programmable logic array
PLC – Programmable Logic Controller. Microprocessor-based system which provides factory or plant automation by monitoring sensors and controlling actuators in real time. PLC is also used as an acronym for Powerline Communications (HomePlug).
PLL – Phase-locked loop. Control system that generates a signal that has a fixed relation to the phase of a “reference” signal.
PMIC – Power Management Integrated Circuit. Circuits used to regulate and control power.
PMM – Power-management mode
Pmod – Small I/O interface boards used to extend the capabilities of FPGA/CPLD and embedded control boards (6- or 12-pin connectors).
PMR – Private Mobile Radio.
PoE – Power-over-Ethernet.
POR – Power-on reset
Potentiometer – Variable resistor in which a wiper sweeps from one end of the resistive element to the other, resulting in resistance that is proportional to the wiper’s position.
Power Fail – Feature in a microprocessor supervisory circuit that provides early warning to the microprocessor of imminent power failure.
Printed Circuit Board (PCB) – Non-conductive material with conductive lines printed or etched. Electronic components are mounted on the board and the traces connect the components together to form a working circuit or assembly.
PROFIBUS – Vendor-independent open fieldbus standard used in manufacturing, building automation, and process control.
PROM – Programmable read-only memory
PRU – Programmable Real-time Unit found in Texas Instruments processors.
PRU-ICSS– Programmable Real-Time Unit Subsystem and Industrial Communication Subsystem. Industrial communications such as EtherCat, Profibus, etc.. compared to a simple PRU.
PSK – Phase-shift keying. Modulation technique in which the phase of the carrier conveys the input signal’s information.
PSW – Program status word
pV-S – Picovolt second(s)
PVR – Personal video recorder
PWM

Method for using pulse width to encode or modulate a signal. Used to control motors, dim lights, etc…
Technique used to modulate the power delivered to a load.

Q

Q Factor – Measure of the quality of a resonant circuit.
QAM – Quadrature Amplitude Modulation. Modulation method in which two signals are used to amplitude-modulate two carriers that are in quadrature (90 degrees out of phase with each other). The two modulated signals are combined.
QFN – “Quad, flat, no-lead” IC package.
QFP – “Quad flat pack” IC package.
QPSK – Quadrature Phase Shift Keying. Phase Shift Keying in which two bits are modulated at once, selecting one of four possible carrier phase shifts (0, 90, 180, or 270 degrees). QPSK allows the signal to carry twice as much information as ordinary PSK using the same bandwidth. QPSK is used for satellite transmission of MPEG2 video, cable modems, videoconferencing, cellular phone systems, and other forms of digital communication over an RF carrier.
QRSS – Quasi-random signal source
Qseven – 70 mm × 70 mm computer-on-module (COM) form factor
QSOP – Quarter small-outline package
Quantization – Process whereby the continuous range of input-signal values is divided into non-overlapping subranges.

R

RAID – Redundant Array of Independent Disks. RAID is a performance and/or reliability enhancing method of storing the data accross multiple hard disks.
RAM – Random access memory
RC – Resistance-capacitance
Receiver – Circuit that accepts signals from a transmission medium and decodes or translates them into a form that can drive local circuits.
Relay – Electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays.
Remote Temperature – Temperature at a location other than at the die of the temperature-measuring integrated circuit.
Resistance – Represented by the symbol R and measured in ohms, is a measure of the opposition to electrical flow in DC systems.
Response Time – The time for a sensor to respond from no load to a step change in load.
RF – Radio Frequency: An AC signal of high enough frequency to be used for wireless communications.
RFI – Radio Frequency Interference.
RFID – Radio Frequency Identification. Method for uniquely identifying an object using a tag or module that carries a unique ID number, or code.
RH – Relative humidity
RISC – Reduced instruction set computer. Computer hardware designed to support a short list of simple instructions.
RMS – Root mean square
ROM – Read-only memory
RS-232 – Serial interface published by the EIA for asynchronous data communication over distances up to a few hundred feet.
RSA – Ppublic key cryptographic algorithm named after its inventors (Rivest, Shamir, and Adelman).
RSSI – Received Signal Strength Indicator (or Indication). Signal or circuit that indicates the strength of the incoming (received) signal in a receiver.
RTC – Real-time clock. Integrated circuit that contains a timer that supplies the time of day (and often, the date). A coin-cell battery is normally used to keep track of the time even when there is no power applied to the system.
Rx – Receive
RZ – Return to Zero

S

Siemen(s). Standard unit for conductance
Lower case s is the standard abbreviation for seconds.

S-UMTS – Satellite-universal mobile telecommunications system
Samples per Second – In data conversion, an analog signal is converted to a stream of numbers, each representing the analog signal’s amplitude at a moment in time. Each number is called a “sample.” The number sample per second is called the sampling rate, measured in samples per second.
Sampling Rate – An A/D converter converts an analog signal into a stream of digital numbers, each representing the analog signal’s amplitude at a moment in time. Each number is called a “sample.” The number sample per second is called the sampling rate, measured in samples per second.
SAN – Storage Area Network. A network infrastructure of shared multihost storage, linking all storage devices and interconnecting remote sites.
SATA – Serial ATA. Computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives and optical drives.
SBGA – Super ball-grid array, a packaging technology.
SBS – Smart Battery Specification (by Duracell).
SCART – “Syndicat des Constructeurs d’Appareils Radiorécepteurs et Téléviseurs”. Also known as Euroconnector or Peritel, a 21-pin connector commonly used in Europe to interconnect satellite receivers, television sets, and other audiovisual equipment (e.g. videocassette recorders). Deprecated.
Schottky Diode – A diode realized via a “Schottky-barrier junction” — a metal-semiconductor junction — rather than the P-N junction used by conventional semiconductor diodes. Schottky diodes are often chosen for their high switching speed and low forward voltage drop.
SCL – Serial clock line
SCLK – Serial clock
SCSI – Small Computer System Interface (pronounced “scuzzy”). Interface standard for connecting peripheral devices to computers. Deprecated.
SCT – Single Chip Transceivers. A single IC that includes data communication transmitter and receiver functions.
SD

Signal detect. Output that indicates when a signal is present.
Secure Digital, a media format for nonvolatile external memory.

SDA – Serial data access
SDK – Software Development Kit
SDO – Serial data out
SDTV – Standard Definition Television. Digital formats that do not achieve the video quality of HDTV, but are at least equal, or superior to, NTSC pictures.
Secure Hash Standard – This standard specifies a Secure Hash Algorithm, SHA-1, for computing a condensed representation of a message or a data file.
Semiconductor

Substance that can act as an electrical conductor or insulator depending on chemical alterations or external conditions.
An electronic device (e.g. a transistor, diode, or integrated circuit) manufactured from semiconductor materials.

SerDes – Serialization/deserialization
Serial Interface – Interface which data is sent in a single stream of bits. Examples include RS-232, I2C, and 1-Wire. Opposed to a parallel interface.
SFF – Small Form Factor
SFP – Small Form Factor Pluggable. Used for network equipment.
SHA – Secure Hash Algorithm. Message digest algorithm developed by the NSA for use in the Digital Signature standard.
Shock Sensor – An acceleration sensor, generally a piezoelectric type, that can measure high acceleration but cannot measure static g forces.
SiGe – Silicon Germanium
Signal-to-Noise Ratio (SNR) – Ratio of the amplitude of the desired signal to the amplitude of noise signals at a given point in time. The larger the number, the better. Usually expressed in dB.
SIM – Subscriber identity module
SLIC – Subscriber-Loop-Interface-Circuit: A telephone line interface.
SMARC – Smart Mobility ARChitecture. Standard for low power systems and computers on module.
Smart Battery – Battery with internal circuitry that provides level of charge status to the host system.
Smartphone – Phone with a microprocessor, memory, screen, and built-in cellular and wireless connectivity. It combines some of the capabilities of a PC in a handset device and typically include Internet connectivity.
SMBus – System Management Bus. A 2-wire serial-interface standard developed by Intel.
SMD

Surface Mount Device. Electronic component that mounts on the surface of a printed circuit board (as opposed to “through-hole” components)
Standard Military Drawing. A U.S. government program for standardized MIL-STD-883 product specifications, to simplify military procurement.

SMP – Symmetric Multiprocessing where an operating system runs across multiple cores.
SMPS – Switch-Mode Power Supply
SMR – Specialized Mobile Radio.
SMTP – Simple Mail Transfer Protocol. Internet standard for electronic mail (e-mail) transmission. See RFC821.
SNMP – Simple Network Management Protocol. Internet-standard protocol for managing devices on IP networks.
SO – Small outline, a package type.
Socket

A TCP application layer connection.
A connector

SOHO – Small Office/Home Office.
SOIC – Small outline integrated circuit, a packaging technology.
SoM – System-on-Module
Solid State – A solid state device or circuit is one that relies on semiconductors rather than mechanical or vacuum tube circuits.
SPI – Serial Peripheral Interface. A 3-wire serial interface.
SPICE – Simulation program with integrated circuit emphasis
Spread Spectrum – Technology that modulates a signal over many carrier frequencies at once. T
SRAM – Static RAM. RAM that does not require a clock to retain its contents.
SSOP – Shrink small-outline package
STB – Set-top Box. Generic name for an appliance between a cable television or satellite signal or IP stream and video display and recording devices.
Strobe – Pulse used for timing and synchronization.
SWAP

Shared wireless access protocol
swap, virtual memory in Linux. Called swap space because processes swap location between fast RAM and slow virtual memory if their priority changes.

Switching Regulator – Voltage regulator that uses a switching element to transform the supply into an alternating current, which is then converted to a different voltage using capacitors, inductors, and other elements, then converted back to DC.
SWT – Set watchdog timeout
Synchronous Digital Hierarchy (SDH) – ITU-TSS International standard for transmitting information over optical fiber.
System on a Chip (SoC) – Integrates most of a system’s elements on a single integrated circuit (chip). It typically combines a microprocessor core along with interface elements and analog and mixed signal functions. Mobile Soc include CPU cores, one or more GPUs, a Video Processing Unit (VPU), an Image Signal Processor (ISP) and more.

T

T1 – Standard for digital transmission in the United States with a capacity of 1.544Mbps.
T3 – Type of data connection capable of transmitting a digital signal at 44Mbps.
TAD – Total accumulated discharge (mA-hr)
TCP/IP – Transmission Control Protocol/Internet Protocol: The protocols or conventions that computers use to communicate over the Internet.
TDD – Time Division Duplex, the second variation of WCDMA especially suited to indoor environments where there is a need for high traffic density.
TDM – Time Division Multiplexing, a scheme in which numerous signals are combined for transmission on a single communications line or channel.
TDMA – Time Division Multiple Access. Method of digital wireless-communications transmission.
TDP – Thermal Design Power gives an indication of the power dissipation under load, useful to select a cooling solution.
TDSCDMA – Chinese Third Generation (3G) telecommunications standard. China’s government allocated three frequency bands: 1880MHZ to ~1920MHz, 2010MHz to ~2025MHz, and 2300MHz to ~2400MHz.
Temperature Switch – Circuit that opens and closes a conductive path based on temperature.
Tesla (T) – Measure of magnetic flux density (B-field), named for engineer and inventor Nikola Tesla.
TFT – Thin-film transistor
Thermal Management – Use of various temperature monitoring devices and cooling methods, such as forced air flow, within a processor or FPGA-based system, to control overall temperature of ICs and internal cabinet temperatures.
Thermal Shutdown – Deactivating a circuit when a measured temperature is beyond a predetermined value.
Thermistor – Temperature-dependent resistor with a high temperature coefficient, usually composed of sintered semiconductor material.
Thermochron – Measures and records temperature. (Thermochron is a trademark of Maxim Integrated.)
Thermocouple – Temperature sensor formed by the junction of two dissimilar metals.
Thermostat – Circuit that indicates whether a measured temperature is above or below a particular temperature threshold or trip point.
Through-Hole – Method for mounting components on a printed circuit board (PCB) in which pins on the component are inserted into holes in the board and soldered in place.
TOPS – Trillion Operatings Per Seconds, often used to describe AI performance
TQFN – Thin version of the QFN package (the JEDEC “W” option) 0.8mm thick.
TQFP – Thin quad flat pack package
TMU – Thermal Management Unit
Transceiver – Device that contains both a transmitter and receiver.
Transformer – Inductive electrical device for changing the voltage of alternating current.
Transistor – Basic solid-state control device which allows or disallows current flow between two terminals, based on the voltage or current delivered to a third terminal.
Transmitter – Circuit that accepts signals or data in and translates them into a form that can be sent across a medium (transmitted), usually over a distance.
TSOC – Thin small-outline C-lead package
TSOP – Thin small-outline package
TSSOP – Thin shrink small-outline package
TTL – Transistor-to-transistor logic
Tubular Motor – Electric motor embedded in a cylindrical form factor.
Tweak – Make small adjustments to a system to improve its performance.
Tx – Transmit

U

uA – Microampere, or microamp: A millionth of an Ampere. Should really use the Greek letter “mu” instead
UART – Universal Asynchronous Receiver-Transmitter. IC that converts parallel data to serial, for transmission; and converts received serial data to parallel data.
UHD – Ultra High Definition – Video resolution up to 4K (3820×2160 – 2160p) or 8K (7680 x 4320 – 4320p). Also referred to as 4K2K, or 8K4K.
UHF – Ultra High Frequency
UMTS – Universal Mobile Telecommunications System. Third-generation cellular standard based on the GSM standard and developed by the 3rd Generation Partnership Project (3GPP).
Uninterruptible Power Supply (UPS) – Device that maintains power in the event of a failure, as long as its battery lasts. When the battery fails, a UPS may contain circuitry that triggers an orderly shutdown.
URL – Uniform/universal resource locator
USB – Universal Serial Bus. Standard port that enables you to connect external devices to computers. Several data transfer rates at supported: low speed (1.5MBps), full speed (12Mbps) high speed (480 MBps), superspeed (5Gbps, USB 3.0), and SuperSpeed 10Gpbs (aka SUPERSPEED+) with USB 3.1.
UV – Ultraviolet
Ultra-Wideband (UWB) – Communications technology that employs a wide bandwidth (typically defined as greater than 20% of the center frequency or 500MHz).

V

V-s – Volt-second(s)
V/F – Voltage-to-frequency
VA – Volt ampere(s)
Vcc – The supply voltage for a circuit is often given as V plus a double-letter suffix.
VCO – Voltage-Controlled Oscillator. Oscillator device in which output frequency is proportional to its input voltage.
VCTCXO – Voltage Controlled, Temperature Compensated Crystal Oscillator.
VCXO – Voltage Controlled Crystal Oscillator.
VDSL – Very High Data-Rate Digital Subscriber Line. Operates at data rates from 12.9Mbps to 52.8Mbps.
VFD – Vacuum Fluorescent Display
VFO – Variable-frequency oscillator
VGA

Variable-gain amplifier
Video Graphics Array – Video standard outputting via a 15-pin D-subminiature connector. Also refers to 640×480 resolution. VGA video output is not limited to 640×480, and can go higher up to 1080p. VGA will soon be deprecated, and HDMI is used in recent hardware

VirtIO – An implementation of device virtualization that is normally applied to networking and storage.
VLSI – Very large-scale integration. Refers to an IC or technology with many devices on one chip.
VoIP – Voice over Internet Protocol: Method for transmission of voice (or fax) calls over the Internet.
Volt – Unit of measure for electromotive force (EMF), the electrical potential between two points.
Vp-p – Peak-to-peak voltage
VPU

Symbol for the pull-up voltage specification (or “Pullup Supply Voltage”).
Video Processing Unit. Hardware block in an SoC that process (decode/encode) and manipulate video streams

W

W – Watt (W) is the unit for measuring power.
Wafer – Semiconductor manufacturing begins with a thin disk of semiconductor material, called a “wafer.” A series of processes defines transistors and other structures, interconnected by conductors to build the desired circuit.
WAN – Wide Area Network. Network that covers an area larger than a single building.
Watchdog – Feature of a microprocessor that monitors software execution in a microprocessor or microcontroller. It takes appropriate action (assert a reset or nonmaskable interrupt) if the processor gets stuck in an infinite execution loop.
Wb – Weber. A measure of magnetic flux.
WB-CDMA – Wideband Code Division Multiple Access. 3G mobile wireless technology capable of supporting voice, video, and data communications up to 2Mbps.
WE – Write enable
WHDI – Wireless Home Digital Interface. Standard enabling wireless delivery of uncompressed HDTV throughout the home with video rates of up to 1080p in the 5GHz unlicensed band.
Wideband – Classification of the information capacity or bandwidth of a communication channel. Wideband is generally understood to mean a bandwidth between 64kbits/s and 2Mbit/s.
WiMax – Worldwide Interoperability for Microwave Access. Long range broadband, wireless access mechanism that can potentially replace DSL and Cable Modem. IEEE 802.16 standard.
Wireless Sensor Network (WSN) – Network of RF transceivers, sensors, machine controllers, microcontrollers, and user interface devices with at least two nodes communicating by means of wireless transmissions.
WLAN – Wireless Local Area Network. Usually Wi-Fi.
WLL – Wireless Local Loop.
WR-RD – Write-read
Write Protect – Any method that keeps data from being over-written.
WTA – Wireless Telephony Application

X

XCO – Crystal clock oscillator. Oscillator that relies on a crystal for its frequency reference.

Y

YIG – Yttrium-iron-garnet. Ferromagnetic material used for solid-state lasers and for microwave and optical communications devices.
Yocto Project – Linux Foundation workgroup whose goal is to produce tools and processes that will enable the creation of Linux distributions for embedded software.
YUV, YPbPr, YCbCr – Also known as component. Video signal compose of three signal Luminance (black and white), and two signals (Cb, Cr) for color.

Z

Zener Diode – Diode manufactured to have a specific reverse-breakdown voltage. Its most common use is as a voltage reference.
ZIF – Zero Insertion Force. A class of IC sockets which clamp the IC pins after insertion, and thus require no downward force on the IC or its pins to insert it into the socket
ZIGBEE – Standard for short-distance, low-data-rate communications using the frequencies and physical and data layers of the IEEE 802.15.4 PHY specification.
Z-Wave – Wireless communications protocol designed for home automation, specifically to remotely control applications in residential and light commercial environments.

Sources