Most Significant Bit (MSB)
In a binary code, the bit or bit position that is assigned to, or represents, the largest quantity or increment that the code can represent. [Fib111]
Minutes of Usage
Memorandum of Understanding
A hardware pointing device used to control the movement of an on-screen cursor. The mouse buttons are then used to select items on the screen.
Moving Picture Experts Group (MPEG)
A voluntary body, which develops standards for digital, compressed moving pictures and associated audio.
Motion Picture Association of America
Moving Picture Experts Group
Video compression standard that requires a minimum of 30 frames per second with CD-quality sound (i.e., 16-bit stereo).
An improved video compression standard over MPEG-1 that offers better resolution at the same 30 frames per second (as MPEG-1). Commonly used by cable television operators and direct broadcast satellite providers to offer digital video services because of its efficient use of capacity, improved quality over analog and stereo sound.
Main Profile at High Level; provides much higher bit-rate system adopted to provide high definition television in wide screen format. [Sat07]
MPEG-4 is a collection of methods defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) (ISO/IEC JTC1/SC29/WG11) under the formal standard ISO/IEC 14496 - Coding of audio-visual objects. Uses of MPEG-4 include compression of AV data for web (streaming media) and CD distribution, voice (telephone, videophone) and broadcast television applications. Initially, MPEG-4 was aimed primarily at low bit-rate video communications; however, its scope as a multimedia coding standard was later expanded. MPEG-4 is efficient across a variety of bit-rates ranging from a few kilobits per second to tens of megabits per second. MPEG-4 provides the following functionalities:
Improved coding efficiency over MPEG-2
Ability to encode mixed media data (video, audio, speech)
Error resilience to enable robust transmission
Ability to interact with the audio-visual scene generated at the receiver [Wik114]
Among the MPEG technologies used in practice, the current MPEG-4 offers the highest efficiency during encoding. The main reason is ACE (Advanced Coding Efficiency) - an encoding algorithm that is used in MPEG-4 for the first time. The object orientation in connection with ACE enables very low data rates. It allows storing a complete video movie in full PAL or NTSC resolution and stereo audio (16 bit, 48 kHz) on a single CD-ROM. For clarification: 700 MB of storage is totally sufficient for most movies that run up to 110 minutes. A movie in MPEG-2 format, on the other hand, requires at the same resolution about 11 times more storage space (DVD with 8 GB). While the data rate of MPEG-2 is coupled very closely to the actual profile, MPEG-4 is scalable over a wide area in the audio as well as in the video stream. Audio signals can be processed from 2 kBit/s to 24 kBit/s while video is variable between 5 kBit/s and 10 Mbit/s. Because of this scalability the audio/video data can be adapted specifically to the actual environment. MPEG-2 is mainly used for large applications: as data format on a video DVD, as data stream in digital television broadcasts and in video editing for digital video broadcasting. [Tom00]
MPEG-7 is an ISO/IEC standard developed by MPEG (Moving Picture Experts Group), the committee that also developed the successful standards known as MPEG-1 (1992) and MPEG-2 (1994), and the MPEG-4 standard (Version 1 in 1998, and version 2 in 1999). The MPEG-1 and MPEG-2 standards have enabled the production of widely adopted commercial products, such as Video CD, MP3, digital audio broadcasting (DAB), DVD, digital television (DVB and ATSC), and many video-on-demand trials and commercial services. MPEG-4 is the first real multimedia representation standard, allowing interactivity and a combination of natural and synthetic material coded in the form of objects (it models audiovisual data as a composition of these objects). MPEG-4 provides the standardized technological elements enabling the integration of the production, distribution and content access paradigms of the fields of interactive multimedia, mobile multimedia, interactive graphics and enhanced digital television. The MPEG-7 standard, formally named "Multimedia Content Description Interface", provides a rich set of standardized tools to describe multimedia content. Both human users and automatic systems that process audiovisual information are within the scope of MPEG-7. MPEG-7 offers a comprehensive set of audiovisual Description Tools (the metadata elements and their structure and relationships, that are defined by the standard in the form of Descriptors and Description Schemes) to create descriptions (i.e., a set of instantiated Description Schemes and their corresponding Descriptors at the users will), which will form the basis for applications enabling the needed effective and efficient access (search, filtering and browsing) to multimedia content. This is a challenging task given the broad spectrum of requirements and targeted multimedia applications, and the broad number of audiovisual features of importance in such context.
MPEG-7 has been developed by experts representing broadcasters, electronics manufacturers, content creators and managers, publishers, intellectual property rights managers, telecommunication service providers and academia. [ISO04]
The MPEG-21 Multimedia Framework initiative aims to enable the transparent and augmented use of multimedia resources across a wide range of networks and devices. MPEG-21 is based on two essential concepts: (1) the definition of a fundamental unit of distribution and transaction (the Digital Item) and (2) the concept of Users interacting with Digital Items. The Digital Items can be considered the “what” of the Multimedia Framework (e.g., a video collection, a music album) and the Users can be considered the “who” of the Multimedia Framework. The goal of MPEG-21 can thus be rephrased to: defining the technology needed to support Users to exchange, access, consume, trade and otherwise manipulate Digital Items in an efficient, transparent and interoperable way. MPEG-21 identifies and defines the mechanisms and elements needed to support the multimedia delivery chain as described above as well as the relationships between and the operations supported by them. Within the parts of MPEG-21, these elements are elaborated by defining the syntax and semantics of their characteristics, such as interfaces to the elements. [ISO02]
The combination of MPEG-4 encoding and decoding and MPEG-7 Multimedia Content Description Interface. [Net09]
Multiprotocol Label Switching; is a mechanism in high-performance telecommunications networks which directs and carries data from one network node to the next with the help of labels. MPLS makes it easy to create "virtual links" between distant nodes. It can encapsulate packets of various network protocols. MPLS is a highly scalable, protocol agnostic, data-carrying mechanism. In an MPLS network, data packets are assigned labels. Packet-forwarding decisions are made solely on the contents of this label, without the need to examine the packet itself. This allows one to create end-to-end circuits across any type of transport medium, using any protocol. The primary benefit is to eliminate dependence on a particular Data Link Layer technology, such as ATM, frame relay, SONET or Ethernet, and eliminate the need for multiple Layer 2 networks to satisfy different types of traffic. MPLS belongs to the family of packet-switched networks. MPLS operates at an OSI Model layer that is generally considered to lie between traditional definitions of Layer 2 (Data Link Layer) and Layer 3 (Network Layer), and thus is often referred to as a "Layer 2.5" protocol. It was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients which provide a datagram service model. It can be used to carry many different kinds of traffic, including IP packets, as well as native ATM, SONET, and Ethernet frames. A number of different technologies were previously deployed with essentially identical goals, such as frame relay and ATM. MPLS technologies have evolved with the strengths and weaknesses of ATM in mind. Many network engineers agree that ATM should be replaced with a protocol that requires less overhead, while providing connection-oriented services for variable-length frames. MPLS is currently replacing some of these technologies in the marketplace. It is highly possible that MPLS will completely replace these technologies in the future, thus aligning these technologies with current and future technology needs. In particular, MPLS dispenses with the cell-switching and signaling-protocol baggage of ATM. MPLS recognizes that small ATM cells are not needed in the core of modern networks, since modern optical networks (as of 2008[update]) are so fast (at 40 Gbit/s and beyond) that even full-length 1500 byte packets do not incur significant real-time queuing delays (the need to reduce such delays — e.g., to support voice traffic — was the motivation for the cell nature of ATM). At the same time, MPLS attempts to preserve the traffic engineering and out-of-band control that made frame relay and ATM attractive for deploying large-scale networks. While the traffic management benefits of migrating to MPLS are quite valuable (better reliability, increased performance), there is a significant loss of visibility and access into the MPLS cloud for IT departments. [Wik117]
Applied Data Communications (A Business-Oriented Approach) James E. Goldman & Phillip T. Rawles, 2004 (ISBN 0-471-34640-3)
Routers Hold key to MPLS Measurement
Multiple Program Transport Streams
Multichannel Video Program Distributor. Includes direct broadcast satellite (DBS) and private cable operators (PCOs).
Multi Quantum Well Laser [Fib111]
Milliseconds; one thousandth of a second or 10-3 seconds. [Fib111]
Media Access Control Service Access Point
Multiple (cable) Systems Operator
Message Transfer Agent
Multimedia Terminal Adapter
Mean Time Between Failure; the length of time during which a system of part of a system should operate without any difficulty. [Arr11]
Message Transfer Part
Mean Time To Failure
Mean Time to Repair
A feedhorn bracket or tray supported at the focal point of a satellite antenna designed to hold 2 or more feed horns used to receive satellite signals from several satellites using just one satellite antenna. [Arr11]
A multicast is a message that is sent out to multiple devices on the network by a host.
Multi-Channel/Multi-Point Distribution (MMDS)
Private service utilizing a very high frequency (2 GHz) to transmit multiple television signals (also called wireless cable).
Multilongitudinal Mode (MLM) Laser
An injection laser diode which has a number of longitudinal modes. [Fib111]
MLM Laser Spectral Graph courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/m
Multimedia Home Platform (MHP)
The Multimedia Home Platform consists of an MHP viewer terminal, including all possible low-to-high functionality implementations, its associated peripherals, and the in-home digital network.
Multimedia Terminal Adapter (MTA)
The device in a PacketCable network that connects the subscriber equipment (such as a telephone) to the network.
Emission at several frequencies simultaneously, generally closely spaced, each frequency representing a different mode of laser oscillation in the resonant cavity. A term that describes optical waveguide that permits the propagation of more than one mode. [Arr11]
A fiber that supports propagation of more than one mode of a given wavelength. [Arr11]
Multimode Fiber Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/m
Dispersion resulting from the different transit lengths of different propagating modes in a multimode optical fiber. Also called modal dispersion. [Fib111]
Multimode Laser Diode (MMLD)
Synonym for multilongitudinal mode (MLM) laser. [Fib111]
Copies of the desired signal that have arrived at the antenna after bouncing from objects between the signal source and the antenna; these signals can either cancel or reinforce each other.
The ability of more than one user to have access to a transponder. [Sat07]
Multiple Reflection Noise (MRN)
The fiber optic receiver noise resulting from the interference of delayed signals from two or more reflection points in a fiber optic span. Also known as multipath interference. [Fib111]
Multiple (cable) Systems Operator (MSO)
A company that operates multiple cable systems.
Multiple Dwelling Units (MDU)
Apartment buildings and condominiums.
A device that allows several users to share a single circuit. It funnels different data streams into a single stream. At the other end of the communications link, another multiplexer reverses the process by splitting the data stream back into the original streams.
A device which combines two or more optical signals onto one communications channel. The signals can be of difference wavelengths (wavelength-division multiplexing) or can occupy different time slots (time-division multiplexing). Combination of information signals from several channels into one single optical channel for transmission. [Arr11]
MUX_DEMUX Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/m
The potential transmission of several feeds of the same cable network with the same programming available at different times of the day. This is seen as one possible use of the additional channel capacity that may be made available by digital compression. Multiplexing is also used by some cable networks to mean transmitting several slightly different versions of the network, for example several MTV channels carrying different genres of music.
User access in which more than one piece of terminal equipment is supported by a single network termination.
Multipoint Conferencing Unit (MCU)
A switching device that interconnects H.323- and T.120-compliant conferencing systems in a multipoint conference.
A connection among more than two data network terminations.
Multipoint Controller (MC)
The H.323 entity that provides control of three or more endpoints in a multipoint conference.
Multipoint Microware Distribution System (MMDS)
A wireless broadband technology for Internet access.
Multipoint Mixing Controller (MMC)
A conferencing device for mixing media streams of multiple connections.
Multipurpose Internet Mail Extensions (MIME)
A specification for formatting non-ASCII data for transport over the Internet.
Multi-quantum Well (MQW) Laser
A laser structure with a very thin (about 10 nm thick) layer of bulk semiconductor material sandwiched between the two barrier regions of a higher bandgap material. This restricts the motion of the electrons and holes and forces energies for motion to be quantized and only occur at discrete energies. [Fib111]
Combines a dual low noise block converter (LNB) output from a SATCOM dish, and in some cases combines RF signals, and sends signals out to multiple satellite receivers. [Cha07]
A passive device installed in cable system feeder lines to provide signal to the subscriber's drop. A multitap is a combination device which contains a directional coupler that has a hybrid splitter connected to its tap port. [Arr11]
Multiple Sub-nyquist Encoder; a high-definition standard developed in Europe that delivers 1125 lines at 60 frames per second. [Fib111]
The FCC rule requiring cable systems to carry all local broadcast television signals in their market.
Multichannel Video Programming Distributor
Mach-Zehnder; a structure used in fiber Bragg gratings and interferometers. Named for the two physicists, Ludwig Mach and Ludwig Zehnder, who developed the underlying principles of the structure, [Fib111]
Mach–Zehnder Interferometer (MZI); developed by the physicists Ludwig Mach and Ludwig Zehnder. It uses two separate beam splitters (BS) to split and recombine the beams, and has two outputs, which can e.g. be sent to photodetectors. The optical path lengths in the two arms may be nearly identical (as in the figure), or may be different (e.g. with an extra delay line). The distribution of optical powers at the two outputs depends on the precise difference in optical arm lengths and on the wavelength (optical frequency). If the interferometer is well aligned, the path length difference can be adjusted (e.g. by slightly moving one of the mirrors) so that for a particular optical frequency the total power goes into one of the outputs. For misaligned beams (e.g. with one mirror being slightly tilted), there will be some fringe patterns in both outputs, and variations of the path length difference affect mainly the shapes of these interference patterns, whereas the distribution of total powers on the outputs may not change very much. [Enc11]
Mach-Zehnder Modulator (MZ Modulator). Lithium Niobate Mach-Zehnder (LiNbO3) modulators are suited for use in metro, long-haul (LH) and ultra long-haul (ULH) optical transport applications.
Diagram courtesy of Fiber Optics 4 Sale, http://www.fiberoptics4sale.com/wordpress/optical-modulators-tutorial-electroabsorption-modulator-eam-and-lithium-niobate-mach-zehnder-modulator-modulator-mz-modulator/
Photograph of LiNbO3 based MZM courtesy of JDSU
The incoming optical signal is split equally and is sent down two different optical paths. After a few centimeters, the two paths recombine, causing the optical waves to interfere with each other. Such an arrangement is known as an interferometer. If the phase shift between the two waves is 0°, then the interference is constructive and the light intensity at the output is high (on state); if the phase shift is 180°, then the interference is destructive and the light intensity is zero (off state). The phase shift, and thus the output intensity, is controlled by changing the delay through one or both of the optical paths by means of the electro-optic effect. This effect occurs in some materials such as lithium niobate (LiNbO3), some semiconductors, as well as some polymers and causes the refractive index to change in the presence of an electric field. The guided-wave LiNbO3 interferometers used to modulate laser beams was fabricated as early as 1980. LiNbO3 has been the material of choice for electro-optic MZ modulator because it combines the desirable qualities of high electro-optic coefficient and high optical transparency in the near-infrared wavelength used for telecommunications. LiNbO3 MZ modulator can operate satisfactorily over a wavelength range of 1300 – 1550nm. It has been widely used in today’s high-speed digital fiber communication. LiNbO3 MZ modulators with stable operation over a wide temperature range, very low bias-voltage drift rates, and bias-free operation are commercially available. High-speed, low-chirp modulators are needed to take advantage of the wide bandwidth of optical fibers. Modulators have become a critical component both in the high-speed time-domain-multiplexing (TDM) and wavelength-division-multiplexing systems (WDM).
Modulators have been traditionally used to modulate a continuous wave (CW) laser to generate the digital signal to be transmitted through a fiber. High-speed modulator with >40GHz bandwidth has been fabricated. Low drive-voltage operation is the key to brining such modulators into practical use because this eliminates the need for high–power electrical amplifiers. There is general a tradeoff between the speed and the drive voltage. The modulator chirp must also be taken into consideration in the link design. The design of the modulator and the associated chirp can be used as a degree of freedom to extend link distance. [Fib11]
N + 1
A formula which refers to the FCC requirements that provide for expansion of channel capacity for non-broadcast use. If the governmental, educational, public access and leased channels are in use 80 percent of the weekdays (Monday through Friday) for 80 percent of the time during any three-hour period for six consecutive weeks, the system operator must expand the system's channel capacity within six months.
Nanoamp; one billionth of an Amp or 10-9 Amps. [Fib111]
Numerical Aperture Mismatch Loss (NA Mismatch)
The signal attenuation that results from differences in NA between optical fibers. Because the optical pattern of one optical fiber gap is larger than the NA of the receiving fiber, some of the rays that travel from the end of one fiber extend beyond the numerical aperture acceptance angle of the other fiber. [Opt09]
National Association of Broadcasters. [Sat07]
NA Mismatch Loss
The loss of power at a joint that occurs when the transmitting half has a numerical aperture greater than the NA of the receiving half. The loss occurs when coupling light from a source to fiber, from fiber to fiber, or from fiber to detector. [Fib111]
A prefix meaning "one-thousandth of a millionth." One billionth (10-9).
One billionth of a second.
North American Number Plan
This medium is capable of carrying voice, fax, paging, and relatively slow-speed data (not full video applications), typically at 64Kbps or less.
Delivery of programming that addresses a specific need or highly focused audience.
National Aeronautics and Space Administration; The U.S. agency which administers the American space program, including the deployment of commercial and military satellites via a fleet of space shuttle vehicles. [Sat07]
National Space Development Agency of Japan. [Sat07]
Network Address Translation
National Cable Telecommunications Association (NCTA)
The trade association for the cable telecommunications industry in the US. Or a voluntary association of cable television operators which, among other things, provides guidance on measurements and objectives for cable television systems in the USA.
National Electric Code® (NEC)
A standard governing the use of electrical wire, cable and fixtures installed in buildings; developed by the American National Standards Institute (ANSI), sponsored by the National Fire Protection Association (NFPA), identified by the description ANSI/NFPA 70-1990. [Fib111]
The North American standard specification for ISDN service.
National Television Systems Committee (NTSC)
Committee, that defined the analog, color television, broadcast standard used today in North America. The standard TV format for North American television transmission is named after this standards committee; the format is 525 lines in a 4-MHz video bandwidth. All TV sets sold in North America are compatible.
A native application is an application written in or compiled to the machine code for the particular processor of the OCAP 1.0 device. Typically, it is written in C, C++, or assembly language and may be supplied with the OCAP implementation or downloaded over the cable.
A native library is a library written in or compiled to the machine code for a particular processor. Typically, it is written in C, C++ or assembly language.
A navigator is a resident application, typically provided by the manufacturer, that the end user can activate at any time. The navigator can be used to select services, applications, and initiate interoperable applications.
A low loss coaxial cable connector used at C-band microwave frequencies. [Arr11]. The N connector (in full, Type N connector) is a threaded RF connector used to join coaxial cables. It was one of the first connectors capable of carrying microwave frequency signals, and was invented in the 1940s by Paul Neill of Bell Labs, after whom the connector is named. Originally, the connector was designed to carry signals of up to 1 GHz in military applications, but the common Type N today handles up to 11 GHz comfortably. More recent precision enhancements to the design by Julius Botka at Hewlett Packard have scaled this to 18 GHz. The male connector is hand-tightened (though versions with a hex nut are also available) and has an air gap between center and outer conductors. The coupling has a 5/8-24 thread. The N connector follows the MIL-C-39012 standard, defined by the US military, and comes in 50 and 75 ohm versions. The 50 ohm version is widely used in the infrastructure of land mobile, wireless data, paging and cellular systems. The 75 ohm version is primarily used in the infrastructure of cable television systems. Connecting these two different types of connectors to each other can lead to damage due to the difference in diameter of the center pin . Unfortunately, many type N connectors are not labeled, and it can be difficult to prevent this situation in a mixed impedance environment.
50Ω N connectors are also commonly used on amateur radio devices (e.g., transceivers) operating in UHF bands. [Wik111]
Suhner, Huber. Radio Frequemncy connector catalogue. pp. 275–276. http://ipaper.ipapercms.dk/hubersuhner/Technologies/Radiofrequency/RFConnectorsEN/.
Golio, Mike (2008). The RF and Microwave Handbook, Second Edition. CRC. pp. 8–7. ISBN 978-0849372179. http://books.google.com/books?id=MCj9jxSVQKIC&printsec=frontcover&source=gbs_summary_r&cad=0.
Terminator, N-male, 50 ohm, 1W
Network Call Signaling
National Cable Telecommunications Association; the major trade association for the cable television industry. [Fib111]
Network Driver Interface Specification
Non Dispersion-Shifted Fiber
Network Digital Video Recorder (DVR)
Near-end Crosstalk (NEXT, RN)
The optical power reflected from one or more input ports, back to another input port. Also known as isolation directivity. [Fib111]
The part of the infrared near the visible spectrum, typically 700 nm to 1500 nm or 2000 nm; it is not rigidly defined. [Fib111]
An entertainment and information service that broadcasts a common set of programs to customers on a scheduled basis. At least initially, NVOD services are expected to focus on delivery of movies and other video entertainment. NVOD typically features a schedule of popular movies and events offered on a staggered- start basis (every 15 to 30 minutes, for example). See also Video-on-Demand. Or video-on-demand with which the user may experience some delay before content begins.
New Entrant Carrier
National Electrical Code
For a given class of emission, the width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under specified conditions. Emissions useful for the adequate functioning of the receiving equipment, e.g., the emission corresponding to the carrier of reduced carrier systems, must be included in the necessary bandwidth. (See Annex J of NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management for formulas used to calculate necessary bandwidth.) Also, the calculated spectral width of an emission. [Placeholder1] [ATI07]
National Electrical Manufacturers Association; organization responsible for the standardization of electrical equipment, enabling consumers to select from a range of safe, effective, and compatible electrical products. http://www.nema.org/ [Fib111]
Noise Equivalent Power
Net Weekly Circulation (NWC)
The estimated number of television households viewing a particular station at least once per week, Monday-Sunday, 6:00 am to 2:00 am, EST. Used to determine whether a station is “significantly viewed” in an area and must be carried by a cable system operating in that area.
(1) Group of radio or television outlets linked by cable or microwave that transmit identical programs simultaneously, or the company that produces programs for them. (2) Collection of computers or other devices that communicate with one another over telecommunications networks.
Network Address Translation (NAT)
A function, typically employed in internet connections that performs address translation. Or a method by which IP addresses are mapped from one group to another, transparent to end users.
Network Address Translation Gateway
NAT gateways operate very much like a router, except messages they receive are addressed to them, not the actual destination of the message—a feature that allows a NAT gateway to connect an entire LAN to the Internet using a single TCP/IP address. When a NAT gateway receives a message from the Internet, it examines the two-byte port number at the end of the To address, looks the port number up in a table, and does a Network Address Translation (NAT) to point the message to the actual TCP/IP address for the destination of the message. To send a message from a computer on a LAN to a destination on the Internet, NAT gateways reverse the process, except they look at the message's From address, records the From address in its port number table, then replaces the From address with its own TCP/IP address and designated port number assignment.
Network Call Signaling (NCS)
A PacketCable signaling protocol based on MGCP for use in a centralized call control architecture, and assumes relatively simple client devices.
A state of overload within a network, where there is a risk of traffic loss or service degradation.
Network Driver Interface Specification (NDIS)
Microsoft's version of the software interface between the transport protocol and the data link protocol, which allows multiple protocol stacks to run over one network adapter.
Network Interface Card (NIC)
A hardware interface card that connects a computer to the network cabling.
Network Interface Device (NID)
Generally an ADSL term, a NID is the interface between the local loop connection to a DSLAM in a Telco Central Office and the customer premise POTS and 10Base-T Ethernet (or other) local computer connection.
Layer 3 in the Open System Interconnection (OSI) architecture that provides network information that is independent from the lower layers; the layer that provides services to establish a path between open systems.
The functions related to the management of data across the network.
Network Management OSS
The functions related to the management of data link layer and physical layer resources and their stations across the data network supported by the hybrid fiber/coax system.
Network Operations Center (NOC)
A large group which is responsible for the day-to-day operations and maintenance of a network.