Technical Glossary
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Displaying 53 glossary terms found.


Unit of measurement for capacitance. More commonly: microfarads.

Fast-Fourier Transform
FFT. Baron Joseph von Fourier discovered that any complex sinusoidal signal could be mathematically represented by an infinite series of sine functions by treating portions of the signal as periodic. A Fourier series is an infinite series of sine functions of the form 1/n sin nx, where n is an integer, and x is an angle. Computers can perform this calculation in real-time displaying a better representation of the audio signal than a real-time spectrum analyzer by displaying the audio waveform.

Federal Communications Commission. The U.S. governmental agency which controls and makes all policy for the use of broadcast airwaves.

Field Emission Display.

Feedback, Acoustic
Unwanted interaction between the output and input of an acoustical system, e.g., between the loudspeaker and the microphone of a system.

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.

1) The degree to which an electronic product accurately reproduces sound. High fidelity systems deliver sound as close as possible to the original. 2) The degree to which a recorded sound is accurate and natural sounding.

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 or two interlaced fields. The refresh rate is 60 Hz.

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.

Fill Factor
Another term for Aperture Ratio which translates into the amount of useful information on the screen.

An electrical circuit that passes alternating currents of some frequencies and attenuates others.

Finite Space
A room with a cubic volume that has definite, definable limits.

A data communication scheme used with digital camcorders, the 1394 FireWire manages the digitization, compression and audio synchronization processes while shooting. This puts broadcast quality video footage directly into your computer or DV (Digital Video) editing system. See 1394 or IEEE-1394.

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).

Focal Length.

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.

1)The term used to describe an even frequency response over the spectrum in which no frequency is accentuated. Usually expressed at 0 dB (no gain). It also denotes no modification of the frequency response (by means of equalization or tone controls). 2) A description that pertains to sound reproduction that is deficient in depth, giving the impression that all reproduced sound sources are the same distance from the listener.

Flat Square Tube
FST. A picture tube that is less rounded than other conventional tubes-therefore called flat. Square refers to the corners. Although not perfectly square, such tubes are more square than conventional tubes.

Fletcher-Munson Curves
The Equal loudness contours plotted by the researchers Fletcher and Munson. Human ears are most sensitive to sound between 1,000 Hz and 4,000 Hz. Above and below those approximate frequencies, a tone must be several dB greater in order to be perceived as equally loud as a tone in the 1,000 Hz to 4,000 Hz range.

Flicker occurs when the electron gun paints the screen too slowly, giving the phosphors on the screen time to fade. Flicker (called Aliasing) also is a line which does not meet the Nyquist requirement of occupying at least two adjacent lines vertically on the raster, at least one in each of the two fields. For example, a computer can make a single scan line much different from those above and below it. Flicker occurs when a single white line appears during field one and a sixtieth of a second later field two without a white line is displayed. Thus, the white line flickers as it is refreshed every other sixtieth of a second or at a 30Hz rate. Scanning television into lines is a sampling process and as such must obey the sampling rules if artifacts are to be avoided. See Twitter.

Vertical roll or instability of a TV picture.

A repetitive echo set up by parallel reflecting surfaces.

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. The expression of a signal with time varying amplitudes as shifts in 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.

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

Focal Point
The point in a lens at which a beam of parallel light rays, traveling parallel to that axis will be made to converge.

1) To be in focus. The best possible resolution of an image, showing the image to be sharp and well-defined. Verb: The act of adjusting the position of a lens to bring the image into focus. 2) In audio focus is the sharp delineation of the "edges" of reproduced sounds.

Focus Coil
An electromagnetic coil that surrounds a video tube and focuses the electron beam.

Folded Lens
This feature effects the lens, in this case electronic, not optical, and improves heat radiation and increases the projection beam current for a somewhat brighter picture.

The art of recreating incidental sound effects in sync with the picture. While watching the movie the Foley artist generates sounds by acting out the events with special props and materials. Common sound effects created by Foley are footsteps, body movements and the handling of small objects. Named after one of its first practitioners.

A specific style and size of printed or displayed character sets.

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

A measurement of light that is emitted or reflected from a surface. 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. Abbreviated: fL.

1) In recording, a quality in which sounds seem to be projected unnaturally forward toward the listener. 2) In loudspeakers, a quality of reproduction that seems to place sound sources closer than they were recorded. Usually the result of an overly prominent midrange, plus a narrow dispersion patter from the loudspeaker.

In interlaced video, a frame is one complete picture. A video frame is made up of two fields, or two sets of interlaced lines, with a total of 525 lines. For the NTSC standard the frames change at a rate of 30 per second. In film, a frame is one still picture of a series that make up a motion picture, with a playback speed of 24 fps (frames per second).

Frame Advance
A feature that enables the user to advance video frames one at a time.

Freeze Frame
See Still Frame.

1) The speed of vibration of a sound wave, measured in cycles per second or hertz. Frequency determines pitch; the faster the frequency, the higher the pitch. The human ear can hear frequencies in the range of 20 to 20,000 Hz. 2) The assigned channel in which a TV station can transmit a signal.

Frequency Modulation
See FM.

Frequency Range
1) In video, refers to the low-to-high limits of a device, such as a computer, projector or monitor. See Bandwidth. 2) In audio, the frequency range, measured in Hertz (Hz), of an audio component is the range of frequencies it reproduces with a flat (linear) frequency response.

Frequency Response
The frequency range over which signals are reproduced within a stated amplitude range. Typically encompassing the range from 20 Hz to 20 kHz (the audible spectrum). Generally expressed in Hz vs. dB. For example: 100 - 5,000 Hz +/- 5dB means that the device can handle a frequency range of 100 to 5,000 Hz with a possible deviation in amplitude within that frequency range of +5 dB to -5 dB.

Fresnel Lens
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 forward. What a Fresnel lens does is reduce the projector's outermost Off-axis rays (the East and West rays) bend angles so that each of the light rays emitted by the projector is bent back just enough so that its direction becomes parallel with the On-axis ray. A Fresnel lens is a fraction of the size and weight of a conventional lens, and the image is more distorted. Because of its lower cost and compact weight and size, the fresnel lens is often used for the condenser lens in overhead projectors and in studio spot lights. See Lenticular Element. Fringe Area - A location that is far enough from the TV broadcast signal to give consumers reception problems, especially if the location has hills, towers or other broadcast signal spoilers.

Front A/V Jacks
This jack pack found on the front of a TV (usually hidden under a panel) is a handy feature especially for hooking up a camcorder or a video game. Newer Rear Projection and Direct-View models also include S-Video inputs as part of the front jack pack.

Front Channel
An an audio signal path directed to one of the three channels used for on-screen sound. In a theatre, the system is equipped so that amplification and speakers are identical for all three; home theatre systems tend to have the center channel loudspeaker unit more compact than the left and right so that it can be conveniently placed on top or below the display device, though the ideal is identically matched loudspeakers, including the two surrounds.

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 Screen
A light reflecting screen for use when the image will be projected from a source in front of the screen.

Front Projector
A video display device that projects an image onto the front of a reflective screen. The same video display device can be positioned to project an image onto the back of a translucent screen for viewing from the front. See Rear Screen Projection.

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

Frequency-Time Curve.

Full-Coat Magnetic
Film print in which the entire width is coated with magnetic oxide. Cinerama and 70mm Todd-AO sound systems utilized 35mm magnetic film to store seven or six audio tracks. See Magnetic Soundtrack.

Full-Stripe Magnetic
Film print with magnetic oxide stripes where sound would be recorded on. These prints are commonly used during stages of producing and mixing of movie soundtracks, with the final mix referred to as the printmaster. See Printmaster.

Function Generator
An audio generator that provides several different waveforms or functions at the desired frequency.

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

The basic pitch of a musical note.