Wired Broadband and Related Industry Glossary of Terms with Acronyms As of 13 June 2011 Compiled By: Conrad L. Young, Director, Broadband Technical Strategy



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Modulation Error Ratio; a measure of the signal-to-noise ratio (SNR) in a digitally modulated signal. Like SNR, MER is usually expressed in decibels (dB). [Zon10] MER over number of symbols, N is defined as:




where
 is the I component of the j-th symbol received
 is the Q component of the j-th symbol received
 is the ideal I component of the j-th symbol received and
 is the ideal Q component of the j-th symbol received.
MESFET

Metal-Semiconductor Field Effect Transistor; similar to a Junction Field Effect Transistor (JFET) in construction and terminology. The difference is that instead of a using a p-n junction for a gate, a Schottky (metal-semiconductor) junction is used. MESFETs are usually constructed in GaAs, InP, or SiC (never silicon), and hence are faster but more expensive than silicon-based JFETs or MOSFETs. MESFETs are operated up to approximately 30 GHz and are commonly used for microwave frequency communications and radar. From a digital circuit design perspective, it is difficult to use MESFETs as the basis for large-scale digital integrated circuits. [Wor11]
Message Authentication Code (MAC)
A fixed-length data item that is sent together with a message to ensure integrity, also known as a MIC.

Message Digest 5 (MD5)
A one-way hash algorithm that maps variable length plaintext into fixed-length (16 byte) ciphertext.


Message Integrity Check
A fixed-length data item that is sent together with a message to ensure integrity.


Message Transfer Agent (MTA)
A program responsible for receiving incoming messages and routing the messages to individual users.


Message Transfer Part (MTP)
The MTP is a set of two protocols (MTP 2, 3) within the signaling system number 7 (SS7) suite of protocols that are used to implement physical, data link, and network level transport facilities within an SS7 network.

Meter



Used to identify the size of a satellite or micro-wave parabolic antenna. One meter equals 3.28 feet. [Arr11]
Mezzanine Compression

Contribution level quality encoded high-definition television signals. Typically split into two levels: high level at 140 Mb/s and low level at 39 Mb/s. For high definition within the studio, 270 Mb/s is being considered. [Fib111]

MFD

Mode Field Diameter
MG
Media Gateway

MGC
Media Gateway Controller

MGC

Manual Gain Control [Arr11]

MGCP
Media Gateway Control Protocol

MH

Medium-Haul; a classification of video performance under RS-250C. Higher performance than long-haul (LH) and lower performance than short-haul (SH). [Fib111]


MHP
Multimedia Home Platform

MHP (Multimedia Home Platform) Connected Resource
An MHP connected resource is a resource used as part of the MHP which, on its own, does not conform to the specification but which is connected to an MHP terminal in such a way that the whole is part of the MHP.


MHP (Multimedia Home Platform) Solution
The MHP solution encompasses the whole set of technologies necessary to implement the MHP including protocols and APIs.


MHP (Multimedia Home Platform) Terminal
An MHP terminal is a single piece of physical equipment conforming to the MHP specification, in particular in that it contains a Virtual Machine and an instance of the MHP API.

MHz
MegaHertz. One million cycles per second. [Arr11]

MIB
Management Information Base


Michelson Interferometer

A Michelson interferometer, as invented by Albert Abraham Michelson, uses a single beam splitter for separating and recombining the beams. If the two mirrors are aligned for exact perpendicular incidence (see the upper figure), only one output is accessible, and the light of the other output goes back to the light source. If that optical feedback is unwanted (as is often the case with a laser, which might be destabilized), and/or access to the second output is required, the recombination of beams can occur at a somewhat different location on the beam splitter. One possibility is to use retroreflectors, as shown in the lower figure; this also has the advantage that the interferometer is fairly insensitive to slight misalignment of the retroreflectors. Alternatively, simple mirrors at slightly non-normal incidence can be used. If the path length difference is non-zero, as shown in both parts of the figure, constructive or destructive interference e.g. for the downward-directed output can be achieved only within a finite optical bandwidth. Michelson originally used a broadband light source in the famous Michelson–Morley experiment, so that he had to build an interferometer with close to zero arm length difference. There are many variations of the Michelson interferometer. For example, a Twyman–Green interferometer is essentially a Michelson interferometer illuminated with a monochromatic point source. It is used for characterizing optical elements. [Enc11]

Michelson Interferometers


Micro

A prefix for one millionth (10-6). [Arr11]
Microbending

Mechanical stress on a fiber that introduces local discontinuities, which results in light leaking from the core to the cladding by a process called mode coupling. [Fib111]

Microbend Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/m



Micrometer

One millionth of a meter or 10-6 meters. Abbreviated μm. [Fib111]
Microsecond

One millionth of a second or 10-6 seconds. Abbreviated μs. [Fib111]
Microshield™

Monolithic microwave integrated circuits (MMICs) package with addition of an integrated shield to reduce emissions. The shield is plated on top of the traditional mold compound and periphery of the substrate. RFMD Patents Issued and Pending.



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