AV/IT Glossary—27 Days of #AVabc—W





Wearable Tech—Wearable technology (also called wearable gadgets) is a category of technology devices that can be worn by a consumer and often include tracking information related to health and fitness. Other wearable tech gadgets include devices that have small motion sensors to take photos and sync with your mobile devices.


WAN-Wide Area Network—A computer network that covers a broad area such as a link across a metropolitan, regional, or national boundary.

Watt—A unit of electrical power used to indicate the rate of energy produced or consumed by an electrical device. One watt is one joule of energy per second.

Waveform—A display of a signal (on an oscilloscope) that shows the magnitude of current or voltage signals with respect to time. By displaying the waveform of a signal on an oscilloscope, the time between cycles can be measured and its frequency can be calculated.

Waveform Monitor—A special oscilloscope used to display and analyze electrical (voltage or current) signals.

Waveguide—An acoustic device built into a loudspeaker enclosure that improves the efficiency of the speaker by confining the movement of a sound wave to travel over a desired path. In brief, a waveguide is a tube-like structure, straight or folded, that couples the motion of the loudspeaker cone to the motion of the air in the tube. This allows a small speaker driver to create clear sound, without distortion, even at the high volume levels required for low frequency reproduction.

Waveguide Dispersion—The distortion of an electromagnetic signal, or in the case of fiber optics, light as it encounters a waveguide and is dispersed into multiple components of different modes or wavelengths.

Wavelength—The distance from one peak to the next between identical points in adjacent waves of electromagnetic signals propagated in space or along a wire. Wavelength is usually specified in meters, centimeters, or millimeters. In the case of infrared, visible light, ultraviolet, and gamma radiation, the wavelength is usually specified in nanometers (10e-9 meter) or Angstroms (10e-10 meter). Wavelength is inversely related to frequency. The higher the frequency of the signal, the shorter the wavelength.

Wavelength Division Multiplexing-WDM—The combination of two or more optical signals at different wavelengths for transmission within a single optical fiber.

Webcasting—Webcasting allows the broadcast of digital media such as audio or video over the Internet which audience members can stream live or access on demand. Essential equipment for webcasting includes computers, streaming servers, production software, recording gear, appliances & more.

Weighted S/N Ratio—The ratio of signal to noise level after mathematical manipulation. The mathematical calculation for audio takes into account the frequency response of human hearing, and for video the limitations of the human eye and the TV/monitor characteristics. This number is usually higher by a few Decibels than the standard S/N ratio (shows better results).

Weighting Filter—A special type of band-limiting filter used in measuring audio loudness levels that “weights”, or gives more attention to, certain frequency bands. Common weighting filter designs include: A-weighting, a wide bandpass filter, centered at 2.5 kHz, that mimics the way we hear (see “Fletcher-Munson Curve”); and C-weighting, generally “flat” frequency response with -3 dB attenuation at 31.5 Hz and 8 kHz.

White—The lightest visible surface created by a reflection of all colored light.

White Balance—An electronic process used in video or digital still cameras* to retain true colors. White balancing is performed prior to shooting a specific scene. The camera is pointed at a white object (a wall, for example) and controls on the camera are adjusted until a hairline in the viewfinder is brought to a particular point. This ensures that the tints* in the recorded images will be natural. White balance, as simple as it seems, can be problematic. Unnatural colors are the result of incorrect white balance. To correct this situation post production, an analog or digital Chroma corrector* is used to restore white balance and normal tints*. Most modern cameras nowadays perform automatic white balance control which eliminates many color aberration problems.

White Level—In television, the signal level that corresponds to the maximum picture brightness. The white level is set by the contrast control.

White Light—A blend of multiple colors of the visible portion of electromagnetic spectrum, resulting in light that is white in color to the human eye.

White Limiter—A device which electronically limits the maximum "white" level of a video signal, in order to avoid "over-burned" images on the screen.

White Noise—Noise with random amplitude (strength) over a wide frequency range. Used to test speakers for resonance and sensitivity. Low levels of white noise can be used to cover up other random noises, for example, in an open office environment.

Wideband—A relative term indicating a high bandwidth.

Widescreen—A video display or projected image with an aspect ratio wider than 1.33. Widescreen TVs have an aspect ratio of 1.78, also expressed as “16:9.”

Wide Screen Projector—A display device that projects a video or computer image on a large screen, mainly for public viewing. The first wide screen projectors had very poor quality and brightness, but today, quality and brightness is very good. The classic wide screen projector has three color tubes - red green and blue, and the image is created on the screen by blending the three colors. One of the most common problems encountered with wide screen projectors was poor alignment of the three tubes. In most high quality projectors, the alignment required to get a good superimposition of the three images on the screen is almost automatic and is much easier than in the past. LCD* (Liquid Crystal Display) TFT* driven screens, which eliminate alignment problems completely, became the heart of a new series of wide screen projectors. The TFT* based projectors offer better price/performance ratios than three tube projectors. Another new generation of projectors is based on DLP / DMD (Digital Micromirrors Device) technology in which a semiconductor chip is covered with hundreds of thousands of micro mirrors that change their angle to a beam of light shining on them. This system creates an image that is much more saturated and has more contrast.

Windowbox—A video image that results from displaying an image of standard (1.33) aspect ratio on a television set of widescreen (1.78) aspect ratio. The picture is presented between black bars to the left and right sides of the image. Contrast with “letterbox.”

Wipe—A visual transition between images during which the edge of one image moves across the screen revealing the next image.

Wire—A single conductive element intended to carry a voltage or electronic signal.

Wireless—Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or all of the communication path. Some monitoring devices, such as intrusion alarms, employ acoustic waves at frequencies above the range of human hearing; these are also sometimes classified as wireless.

WLAN—A wireless local area network (WLAN) is a wireless distribution method for two or more devices that use high-frequency radio waves and often include an access point to the Internet. A WLAN allows users to move around the coverage area, often a home or small office, while maintaining a network connection. A WLAN is sometimes caledl a local area wireless network (LAWN).

WMF-Windows Metafile Format—A graphics vector file format developed for Microsoft Windows®, useful in DTP and graphics application.

Woofer—A loudspeaker designed to reproduce low frequencies.

Workstation—A type of computer used in design or development work, such as engineering and CAD, requiring a moderate amount of computing power and high-resolution graphics.

Wow—A low pitch audio artifact caused by speed fluctuation in the playback device.

Wrap-Around—A video problem that occurs when the left picture information is displayed on the right side of the screen and the right picture information is displayed on the left side of the screen, separated by a vertical bar.

WSXGA—“Wide-SXGA” defines a class of SXGA displays with a width resolution sufficient to create an aspect ratio of 16:9. Resolution is defined as the number of individual dots that a display uses to create an image. These dots are called pixels. A WSXGA display has 1920 to 1600 horizontal pixels and 1080 to 900 vertical pixels respectively that are used to compose the image delivered by the projector.

WWW-World Wide Web—An international network of subscriber sites where information in the form of text and/or graphics is made available to computer users (Web site visitors).

WXGA— “Wide-XGA” defines a class of XGA displays with a width resolution sufficient to create an aspect ratio of 16:9. Resolution is defined as the number of individual dots that a display uses to create an image. These dots are called pixels. A WXGA display has 1366 to 1280 horizontal pixels and 768 to 720 vertical pixels respectively that are used to compose the image delivered by the projector.


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