Parts Express - Tech Terms Glossary

Tech Terms Glossary

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Magnetic Shielding: Speakers are magnetically shielded, preventing blurring and distortion of TV images.

Manual Iris Lens: A lens with a manual adjustment to set the iris opening (F stop) in a fixed position. Generally used for fixed lighting applications.

Matrix Switcher: A switcher able to route any of its (camera) inputs to any of its (monitor) outputs, they often includes telemetry control.

Mechanical Focus (back-focus): The mechanical aligning of the imaging device with the focal point of the lens; it is most important on zoom lenses to be sure the image stays in focus throughout the zoom range.

Microfarad (µfd or MFD): Unit of measure for capacitance. One millionth of a farad.

Millihenry (mH): Unit of measurement for inductance. One one-thousandth of a Henry.

Minimum Object Distance (MOD): The closest distance a given lens will be able to focus upon an object. This is measured from the vertex (front) of the lens to the object. Wide angle lenses generally have a smaller MOD than large focal length lenses.

Mms: The mechanical mass of a loudspeaker diaphragm assembly including the air load.

Modulate: To change or vary some parameter such as varying the amplitude of a signal for amplitude modulation or the frequency of a signal for frequency modulation. The circuit which modulates the signal is called a modulator.

Modulator: Often used to combine or convert one or more types of signal into a single "modulated" signal. Examples: CD changer RF modulator: modulates CD audio into an RF antenna signal to be heard with an FM radio. Also a UHF or VHF modulator converts separate audio and video signals into a single modulated RF antenna signal.

Monochrome: Having only one color. In television it is black and white.

Monochrome Signal: In monochrome television, a signal for controlling the brightness values in the picture. In color television, the signal which control the brightness of the picture, whether the picture is displayed in color or in monochrome.

MOSFET (Metal Oxide Semiconductor Field Effect Transistor) Power Supply: High-quality transistors that, when used in an amplifier, deliver high peak current with a shorter signal path and faster response time. This results in enhanced, more clearly defined audio, especially during louder music passages.

Moving-coil Cartridge (MC): System in a cartridge in which a coil moves to generate an electromagnetic force. Features low impedance and special characteristics.

Moving-magnet Cartridge (MM): System in a cartridge in which a magnet moves to generate an electromagnetic force. Easy-to-use and most common type.

MPEG1 (Motion Picture Experts Group format, version 1): The earliest form of digital compression used by the DSS program providers to transmit audio/video information. The main advantage of MPEG technology is the transmission of more channels in what is normally a limited amount of space or band width.

MPEG2 (Motion Picture Experts Group, version 2): The most advanced form of digital compression, currently used by the DSS program providers to transmit audio/video information. It continues to have all the advantages of MPEG1 but also helps improve certain picture quality transmission problems, e.g., motion tiling. The program providers started using this new compression technology in mid- to late-1995.

MTS (Multi-channel TV Sound): An RF signal that carries more than one audio signal. Used for stereo audio, in many cases.

Multimedia: The presentation of multiple media at once. Usually associated with computer software and hardware that perform this function together, like games and CD-ROM packages.

Multiplex: To transmit two or more signals simultaneously on a single wire. Used in TV, CATV, video distribution (audio and video on the same line) and FM stereo broadcasting (left and right audio).

Multi-Room Distribution: The ability to distribute a DSS signal to multiple television sets. Currently the dual LNB DSS system is capable of sending the signal to any number of IRDs, while the single LNB unit feeds only one IRD.