Please select a letter for terms starting with that letter:

- F -

Focus
To clarify a blurry image.

Fades, Wipes, Dissolves
Different special effects used in presentations to bring an image to the screen. In most multimedia presentations, images can sparkle on, wipe on, snap on, etc.

Fall Time
A measurement of the time it takes for the trailing edge of a pulse to fall from a high reference value (typically 90%) to a low reference value (typically 10%) of its amplitude.

Farad
Unit of measurement for capacitance. More commonly; microfarads.

Federal Communications Commission
A unit of the U.S. Government that monitors and regulates communications.

Feedback
The reinforcement of correct responses or the correction of errors by the computer system or instructor.

Ferro-Electric
High contrast LCD technology in development.

FCC
Acronym for Federal Communications Commission.

Fiber Optic
A transmission medium designed to transmit digital signals in the form of pulses of light. Fiber optic cable is noted for its properties of isolation from radio frequency and electromagnetic interference, as well as resistance to electrostatic contamination.

Field
In interlaced video, it takes two scans on a screen to make a complete picture, or a "Frame". Each scan is called a "Field". Sometimes these are referred to as "field 1 and field 2". One-half of a full television scanning cycle (1/60^th of a second NTSC, 1/50^th of a second PAL/SECAM). When interlaced, two fields combine to make one video frame, each field scanning alternate lines.

File
The defined area of storage for a discrete group of data. 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.

Firewire
A data communications scheme used with digital camcorders, the IEEE 1394 Firewire manages the digitization, compression and audio synchronization processes while shooting. This puts broadcast quality video footage directly into a computer or digital video editing system.

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.

Flicker
An alternating change of light intensity, typically perceived at a rate of a few Hertz to 60 Hz when viewing static images such as text. Flicker can occur when the electron gun paints the screen too slowly, giving the phosphors on the screen time to fade before it is refreshed.

Flow Chart
A diagram or map of interactive logic that represents the possible paths a user may take through a program.

FM
Acronym for Frequency Modulation.

Focal Length
The distance between the center of a lens and the point where the image comes into focus. In projection, shorter focal means larger image on the screen for any given projection distance. A fundamental measure of lens performance, often expressed in millimeters.

Focus
The picture adjustment control that adjusts the CRT electron beams to control the sharpness of the display. May increase the amount of picture "noise".

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
The luminance (brightness) resulting from a surface emitting a luminance flux of one lumen per square foot. The luminance of a perfectly reflecting surface receiving an illumination of one foot-candle.

FPS
Acronym for Frames per second.

Fractional T1
FT-1 or fractional T-1 refers to any data transmission rate between 56 Kbps and 1.544 Mbps. It is typically provided by a carrier in lieu of a full T-1 connection and is a point-to-point arrangement. A specialized multiplexer is used by the customer to "channelize" the carrier's signals.

Frame
A single, complete picture in a film recording or video. A video frame consists of two interlaced fields of either 525 scan lines (NTSC) or 625 scan lines (PAL/SECAM). Film runs at 24 frames per second. In interlaced video, a Frame is one complete picture.

Frame Grab
Electronically capturing and storing one screen of information.

Frequency Modulation
A method of combining an information signal with a carrier signal so that it may be transmitted. FM uses the information signal to add to, and subtract from, a carrier frequency, thus "modulating" the carrier frequency. Example: audio frequency is "modulated" onto a radio frequency (RF) and transmitted. An FM radio receives the transmitted signal and removes (demodulates) the RF, producing a copy of the original audio.

Frequency Range
Refers to the low-to-high limits of a device, such as a computer, projector or monitor. Also, "bandwidth".

Fresnel Lens
A flat lens technology that uses molded concentric prism rings to create a wide range of lens types. A method of focusing light with a thin, flat lens by cutting circular grooves into its surface. The grooves act like concentric prisms to bend and focus the light. A Fresnel lens is a fraction of the size and weight of a conventional lens, and the image is more distorted.

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.

Front Projection
Projecting onto the reflective surface of an opaque screen material for viewing from the same side. As opposed to rear projection.

FSTN
Acronym for Film compensated SuperTwist Nematic LCD.

Function Keys
Keys that are programmed to perform specific tasks.

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