AV/IT Glossary—27 Days of #AVabc—F





Frame Rate—The frequency at which an imaging device produces unique, consecutive images called frames. The term applies equally to computer graphics, video cameras, film cameras, and motion capture systems. Frame rate is most often expressed in frames per second (FPS) and sometimes in progressive scan monitors as hertz (Hz). It can also be seen as refresh rate or vertical scan rate.



F connector—A type of plug used for RF video connections, such as those used to connect TV antennas and cable TV to televisions and VCRs.

Fabry-Perot-FP—A standard laser diode that uses a laser oscillator comprised of two mirrors with an amplifying medium between them.

F Connector—A type of plug used for RF video connections, such as those used to connect TV antennas and cable TV to televisions and VCRs.

Fabry-Perot-FP—A standard laser diode that uses a laser oscillator comprised of two mirrors with an amplifying medium between them.

Fade, Fade-to-black—A gradual dissolve to another picture, often an all black screen.

False Contouring—A picture distortion in digital displays in which dark areas appear as solid blotches. field The odd- or even-numbered lines of a frame.

Fan-Out Kit—In fiber optics, a kit designed for use with loose tube cable with bare fiber bundles in each buffer tube. The kit enables termination as well as protection of these bare fibers.

Far-End Crosstalk (FEXT)—Defined as a measure of the unwanted signal coupling from a transmitter at the near-end into a neighboring pair measured at the far-end. Figure 4 is the illustrated example. The signal is transmitted on the orange pair and the red arrow indicates the FEXT coupling.

Far End—In videoconferencing, the party or group you are connecting to at the distant site.

Farad—Unit of measurement for capacitance which stores one coulomb of electrical charge when one volt is applied. More commonly, stated in picofarads, or one-millionth of one-millionth (10e-12) of a farad.

Fault—In fiber optics, any part of an optical fiber that deviates from normal performance.

Fault Finder—A simplified optical time domain reflectometer – OTDR, an instrument used to detect breaks within a run of optical fiber. Also known as a Fiber Break Locator.

FCC-Federal Communications Commission—The US governmental agency that controls and makes all policy for the use of broadcast airwaves.

FED-Field Emissive Display—FED technology is similar in operation to CRTs in that phosphor is excited by a stream of electrons traveling through a vacuum. “Emissive” refers to the light-emitting characteristic of the display; unlike LCD flat panel displays, a backlight is not required for image display. Because FEDs are emissive, they allow equal brightness at all viewing angles.

Feedback—(also known as Larson effect) The phenomenon where the sound from a loudspeaker is picked up by the microphone feeding it, and then reamplified again and again. The resulting loop between audio input (the microphone) and audio output (the loudspeaker) results in a scream or squeal emitted from the loudspeaker. Feedback is determined by the resonant frequencies in the amplifier and loudspeakers, the acoustics of the room, the design of the microphone, and the relative positions of the microphone and loudspeaker.

FEP-Fluoro Ethylene Polymer—Teflon FEP is used as a Foaming Dielectric for all of our Plenum Rated Coax Products

Ferrule—A precision tube which centers an optical fiber and provides stabilization and precise alignment. A ferrule may be part of a connector or a mechanical splice.

Ferrule Connector-FCA—Screw-type optical fiber connector that features a keying mechanism. FCs are typically designated as FC/PC, FC/SPC, or FC/APC to denote physical contact, super physical contact, or angled physical contact, respectively.

FFT-Fast Fourier Transform—Converts analog waveforms into a form that can be easily analyzed for DSP applications.

Fiber—The basic optical transmission element. The components of a fiber include the core, surrounded by the cladding, and then a coating for protection. Specific optical properties of the core and cladding enable light to be contained within the core as it travels along the fiber.

Fiber Break Locator—An instrument used as simplified method of locating breaks within an optical fiber. Also known as a Fault Finder.

Fiber Coating—A coating surrounding the cladding of an optical fiber during the draw process to protect the fiber from handling and the environment.

Fiber Distribution Unit-FDU—An enclosure that houses and organizes groups of optical fibers.

Fiber Optic Cable—A telecommunications cable comprising one or more optical fibers.

Fiber Optic—A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

Fiber Surface Finish—A term describing or denoting the quality of the polishing at the end of a fiber.

Fiber to the Building/Business-FTTB—Fiber optic service to a business or building.

Fiber to the Curb-FTTC—Fiber optic service to a node within a residential neighborhood. The node in turn feeds several homes via copper wiring.

Fiber to the Desk-FTTD—Fiber optic runs to individual desktops.

Fiber to the Home-FTTH—Fiber optic service to individual homes.

Fibre Channel—An industry standard for connecting computers for gigabit-speed transmission over twisted pair and optical fiber at distances up to 10 km.

Field—A field is one half of a standard television frame, containing every other line of information. Each standard video frame contains two interlaced fields, sometimes referred to as field 1 and field 2. In the NTSC video system, a field contains 262.5 lines and a frame contains 525 lines. In the PAL video system, a field contains 312.5 lines and a frame contains 625 lines.

Figure 8—In fiber optics, a method of polishing the end of a connector in a figure 8 pattern to minimize scratches.

File—In computers, a record of related information that may be stored in memory, on a disk, or other media. Files can contain text, graphics, data, or programs.

Fillers—Non-conducting materials incorporated into the construction of a fiber optic cable to add roundness, flexibility, tensile strength, or a combination of all three.

Fill Factor—In a digital display device, the ratio of pixel area to nonpicture areas between the pixels. The higher the fill factor, the smootherlooking the image.

Filter—In general, a filter accepts the desired and rejects the undesired. Every filter has a specific purpose. In electronics, for example, if you have some high frequency noise mixed with the signal that you want, then a lowpass filter is used to pass the signal and reject the (high frequency) noise. In software, a filter allows the application to open a file of a specific format. Also see "Band pass filter", "High pass filter", and "Low pass filter."

Firewall—A device that manages access of devices outside a network into a network, typically into a building or an enterprise. A firewall prevents unauthorized access to a network.. They are also used to check on data delivered to and from a network to ensure the information is non-damaging.

FireWire™—A trademark of Apple. Also known as 1394 or IEEE-1394. A data communication standard used primarily with digital camcorders, 1394 FireWire manages the data transfer and tape transport control processes when transferring DV (digital video) to your computer or DV editing system. FireWire supports data transfer rates of 100 to 400 Mbps.

First Surface Mirror—The front of a mirror. In mirrors intended for A/V applications, the first surface is coated with a reflective material to prevent double images (ghosting).

Fixed-Pixel Display—A video display device that uses an array of fixed pixels to create the image. Examples include LCD, DLP, LCoS, and plasma. Contrast with a CRT-based display that has no fixed pixel structure.

Fixed-Pixel Scaler—An image scaler that outputs only a single resolution to a fixed-pixel display. A range of output resolutions is unnecessary because the output resolution is factory set for the display with which the scaler is used.

FL-Focal Length—The distance between the center of a lens and the point where the image comes into focus. In projection, a shorter focal length yields a larger image on the screen for any given projection distance.

Flash Memory—A special version of an EEPROM that can be rewritten while in its functioning environment, instead of having to be removed and reprogrammed in a special device. Example: memory for a digital camera.

Flat (response)—A theoretical ideal for audio components, especially speakers, that represents a frequency response that does not deviate from a flat line over the audible frequency spectrum. A flat response, though ideal, is impossible in real world listening due to the speaker itself and its interactions with the room and various surfaces within the room. All speakers will fluctuate above and below the ideal flat response, but speakers that stay within two or three dB of a flat response are considered very linear and very nearly flat in their response.

Flat Field—A solid field of color used to calibrate monitors and projectors. A full white flat field is typically used to evaluate the uniformity of a projected image.

Flat Polish—In fiber optics, a condition at a ferrule where the endfaces of a fiber optic cable and the ferrule tip are polished flat.

Fletcher-Munson Effect—Also referred to as “equal loudness contours.” Fletcher and Munson, researchers at Bell Labs, first measured the sensitivity of human hearing at various volumes and frequencies. Fletcher and Munson found that human hearing is dependent on loudness, and that the ear is most sensitive in the range of 3 kHz to 4 kHz. Sensitivity falls off rapidly at lower frequencies and somewhat more slowly at higher frequencies. Sounds in frequencies below and above this range need to be louder (more powerful) in order to be heard clearly. The loudness control found on audio reproduction systems is designed to compensate for the Fletcher-Munson effect.

FLI/FLC—Animation flick files created by Autodesk™ software, such as Animator™ or Animator Pro. The FLI/FLC file system contains a series of consecutive compressed frames or images that can be replayed as an animation sequence using a special program. This format is widely used in computer generated animations and in clips used for video.

Flicker—An annoying visual phenomena mainly related to the interlacing of video fields, which show up as small vibrations on the screen. Typically perceived at a rate of a few Hertz to 60 Hz when viewing static images such as text. Flicker also appears when static images are displayed on the screen, as in computer generated text when transferred to video. Poor digital image treatment, as in low priced standard converters (going between PAL and NTSC), will create an annoying flicker on the screen. There are several electronic techniques to minimize flicker, such as line averaging and filtering.

Floppy Disk—An almost obsolete magnetic storage device used in computers. Floppy disks store mainly digital data, text and graphics, and computer programs. Floppy disks came in two major sizes: 5 1/4 inch and 3 1/2 inch. The 3-1/2 inch disks are more rigid than the 5 1/4-inch version. Both were subdivided into low density (double density) and high-density types, storing 360KBytes and 1.2MBytes on the 5 1/4-inch format, and 720Kbytes and 1.44Mbytes on the 3 1/2-inch format. Some developments in this field have extended storage on a 3 1/2-inch disk to 2.8MBytes and above. In comparison to hard disks, the advantages of floppy disks are low price and portability, while the disadvantages are slow access time and limited storage. New media formats - magnetic and optic based - are replacing the floppy disks, having much larger storage capacities (from hundreds of megabytes up to several gigabytes), faster access times and ever lower prices.

Focus—To adjust a lens to make the image appear sharp and well defined. The best possible resolution of an image, showing the image to be sharp and well defined.

Focus Coil—Deflection coil. An electromagnetic coil that surrounds a video tube and bends the electron beam onto a screen.

Foley Sound—Effects added to a film soundtrack, such as footsteps and doors closing.

Foot Candle—A unit of illumination from one candle at a distance of one foot. Equal to one lumen incident to one square foot.

Foot-Lambert (fL)—A measure of the amount of light from a video display device.

Format (video)—There is an enormous variety of video formats. They vary in tape width - 4mm, 8mm, 1/2 inch, 3/4 inch, 1 inch, etc.; in signal formats - composite, YC and component video; and in operation - analog or digital. In addition, digital formats themselves take various forms - no single standard prevails. Also, all formats exist in PAL, NTSC and SECAM and their sub-standards, which implies that any video production studio requires an extensive range of interface devices to enable equipment designed for a specific format to work with devices designed for other formats.

Forward—A description of a sonic presentation in which sounds seem to be projected forward, toward the listener.

Forward Error Correction (FEC)—A system of error control for data transmission, whereby the sender adds redundant data to its messages, also known as an errorcorrection code. This allows the receiver to detect and correct errors (within some bound) without the need to ask the sender for additional data. The amount of FEC required to guarantee delivery is not certain. Each application must consider the predictability of the network and the amount of protection that is desired.

FOTS-Fiber Optic Transmission System—A communication system using fiber optic cables

FPC—Front Panel Controller, Extron’s term for the front panel control system used with larger matrix switchers such as the Matrix 3200/6400 and Matrix 12800 series models. The FPC provides simple, touch-of-a-button control of the matrix switcher and eliminates the need for a computer or third party control system to operate the matrix switcher.

FPS—Frames Per Second. A measure of information that is used to store and display motion video. Each frame represents a still image and displaying frames in succession creates the illusion of motion. The more frames per second (fps), the smoother the motion appears.

Frame—In interlaced video, a frame is one complete picture. A video frame is made up of two fields, or two sets of interlaced lines. In film, a frame is one still picture of a series that makes up a motion picture.

Frame Grabber—An electronic device that captures a video frame or field and stores it on a digital storage device, e.g., hard disk, memory card, floppy disk etc.

Frame Lock—Multiple video sources delivered together, which maintain frame synchronization are frame locked. Frame lock is required for delivery of stereoscope 3D imagery consisting of two locked signals or 4k resolution images which are built up using four, synchronized HD video signals.

Frame Rate—The frequency at which an imaging device produces unique, consecutive images called frames. The term applies equally to computer graphics, video cameras, film cameras, and motion capture systems. Frame rate is most often expressed in frames per second (FPS) and sometimes in progressive scan monitors as hertz (Hz). It can also be seen as refresh rate or vertical scan rate.

Frame Relay—Public, connection-oriented packet service based on the core aspects of the Integrated Services Digital Network. It eliminates all processing at the network layer and greatly restricts data-link layer processing. It allows private networks to reduce costs by using shared facilities between the end-point switches of a network managed by a Frame Relay service provider. Individual data-link connection identifiers (DLCIs) are assigned to ensure that each customer receives only its own traffic.

Frame Synchronizer—Stores each incoming frame of video and releases it as the next frame comes in. Frame synchronizers convert analog video to digital and are typically used to synchronize two or more sources.

Freeze Frame—A process which catches and freezes one TV/video frame on the screen. Freeze frame can be done in an electromechanical way, by stopping the VCR’s tape advance and re-scanning the same frame over and over again, or by electronic means by storing the whole frame in digital-chip memories. Digital freeze-frame is one of special effects* that are performed by a special effects generator* or a TBC*

Frequency—The number of times a particular event happens per a given time. In A/V, the number of complete cycles per second of a musical tone or electronic signal, expressed in Hertz (Hz).

Frequency Division Multiplexing-FDM—The combining of two or more signals into a single carrier signal for transmission through FM – frequency modulation. Each signal modulates the carrier signal at a different region of the frequency spectrum.

Frequency Domain—The means of representing a signal as a plot of amplitude (normally on the vertical axis) versus frequency (normally on the horizontal axis). A spectrum analyzer represents signals in the frequency domain. Also see "Time domain."

Frequency Modulation—A low frequency signal modulates (changes) the frequency of an RF signal of a much higher frequency (causing it to move around the basic carrier frequency) - the process is called frequency modulation or FM. This system is extensively used in broadcast radio transmission, as it retains high signal quality. FM is used in video to record signals on videotape. The FM system is less prone to interference and is therefore used in higher quality equipment.

Frequency Range (audio)—The range of frequencies between high and low end points; for example, in audio, the frequency range of the human ear is said to be 20 Hz to 20,000 Hz. Individual speaker elements like woofers, midranges and tweeters serve different frequency ranges within the overall audio frequency range.

Frequency Range (video)—Refers to the low-to-high limits of a device, such as a computer, projector, or monitor. Also see "Color phase."

Frequency Response—The frequency range over which signals are reproduced within a stated amplitude range. Generally expressed in Hz vs. dB. For example: 100 - 5000 Hz +/- 3dB means that the device can handle a frequency range of 100 to 5000 Hz with a possible deviation in amplitude within that frequency range of +3 to -3dB.

Frequency Synthesis—A term used in radio frequency transmissions for the generation of a stabilized high frequency signal. The frequency steps are derived from a crystal-stabilized frequency. Using a chain of switches, a wide range of high frequency signals can be generated from the same low frequency crystal oscillator. This process is mainly used in complex broadcast equipment for RF* modulation and transmission.

Fresnel Lens—A thin, flat lens made by cutting concentric circular grooves into its surface. The grooves act like prisms to bend and focus light. The Fresnel lens is often used for the condenser lens in overhead projectors and in studio spotlights.

Fresnel Reflection—The partial reflection of light that occurs at the boundary between two materials with different indexes of refraction. In fiber optics, this is considered a loss when light is partially reflected at a glass-air interface.

Front porch—The black or blanking portion of the composite picture signal lying between the leading edge of the horizontal blanking pulse and the leading edge of the corresponding horizontal sync pulse. Also see "Blanking."

Front Projection Screen—A light-reflecting screen used when the image is projected from a source in front of the screen. Also see "Rear projection screen."

Front Screen Projection—To project an image from the audience’s side of a light-reflecting screen.

FTP-File Transfer Protocol—A protocol used to transfer files over a TCP/IP network (Internet, UNIX, etc.). For example, after developing the HTML pages for a Web site on a local machine, they are typically uploaded to the Web server using FTP.

Full Duplex—The ability of a device or line to transmit data simultaneously in both directions.

Full Duplex Operation—When data is being both sent and received simultaneously. (i.e., sound cards, network interface cards, hubs)

Fully Loaded—Refers to the condition when all inputs (in the case of a switcher) or all outputs (in the case of a distribution amplifier) or both (in the case of matrix switchers) are connected to loads/devices, that is, the product has a maximum load connected. This is pertinent because if a product is not properly designed, the voltage and the bandwidth can decrease and the signal can drop out as more and more loads are connected, or crosstalk can be a greater problem as more signals appear on the inputs or outputs.

Function Keys—Keys that are programmed to perform specific tasks, such as macro-operations.

Fundamental Rejection—Usually expressed in dB, the amount by which a total harmonic distortion (THD+N) analyzer rejects the fundamental component of the input signal. The lowest measurable distortion of THD+N analyzer is limited by the fundamental rejection, along with several other attributes. Also see "THD" and "THD+N."

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