Technical Glossary
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Displaying 42 glossary terms found.


Early Reflection
Reflected energy that occurs in close proximity to the source, but is slightly out of sync (time/phase ) with the source information.

A distinctly discernible reflection or repetition of the source signal. The term is often used incorrectly to refer to reverberation, which consists of multiple decaying reflections so closely spaced that they are indistinguishable from one another.

Extended Definition Betamax. A consumer/professional videocassette format offering 500-line horizontal resolution and Y/C connections. Can play Beta and SuperBeta tapes. Instead of 5.6 MHz, as with LaserDisc and DVD, the luminance carrier signal is 9.3 MHz producing over 500 lines of resolution with Y/C Video output.

Edge Sharpening
A technique for increasing the apparent sharpness and focus of picture outlines. Also known as Enhancement.

Enhanced Definition Television. A television system featuring advanced encoding and transmission methods. Not as sophisticated as HDTV (high definition television), this first-generation system is compatible with existing TV sets and transmission methods.

Electrically Erasable Programmable Read Only Memory. An IC chip which is capable of storing software instructions or data and retains that information when power is removed. The information in an EEPROM can be erased by exposing it to an electrical charge. See Flash Memory.

Early, early sound. Structure-borne sound may reach the microphone in a room before the air-borne sound because sound travels faster through the denser materials.

Energy-frequency curve.

The reference is to sound effects-the non-musical elements on a film soundtrack other than dialogue.

Energy-frequency-time curve.

Electronics Industries Association. The association which determines recommended audio and video standards in the U.S.

EIA - RS-170
The standard broadcast sync as determined by the Electronics Industries Association. Commonly called EIA sync

EIA Sync
The standard broadcast sync, also called EIA-RS-170.

Electro-Magnetic Focus
There are permanent magnet focus systems in projectors. The better Electro-Magnetic focus systems also have the ability to control beam spot shape over the entire surface of the CRT. This is critical to picture resolution. The electro-magnetically focused projector should have a far better detail capability than a electro-static device. That said, a good electro-statically focused projector could present better detail than a poor implementation of electro-magnetic focus. Then there are degrees of implementation in electro-magnetic focus. One manufacturer may do a better job than another. Often times, electro-magnetic focus is better implemented on projectors with larger CRTs. The larger CRT carries with it the potential for more picture detail so manufacturers often follow through with better drive and focus electronics. See Electro-Static Focus.

Electro-Magnetic Interference
EMI. A type of interference caused by current flowing through wires in close proximity to audio cables. The magnetic field around the power cables makes its way into the audio cables, causing interference (hum, buzz, etc). Also caused by fluorescent lights, neon lights, switching loads (HVAC equipment), computers, RF transmitters, car ignitions, etc.

Electro-Static Focus
Also referred to as electro-static deflection. A CRT tube which focuses the electron beam without the use of heavy deflection coils by using voltage instead of current. Used more on small CRTs, such as oscilloscopes because, with larger CRTs, higher voltages are required, which can emit harmful x-rays. A good electro-statically focused projector could present better detail than a poor implementation of electro-magnetic focus. See Electro-Magnetic Focus.

Electron Beam
The thin stream of electrons in a picture tube that scans the scene to produce a picture.

Electron Gun
The device in the CRT that produces the electron beam that is attracted to the phosphors on the face of the CRT; this activates the phosphors thus causing them to emit red, green, or blue light and create visual images on the screen.

Electronic Industries Association
EIA. The trade association which determines recommended audio and video standards in the United States.

Electrostatic Speaker
A type of loudspeaker that creates sound via a vibrating surface that is electrically charged.

A process that boosts the high-frequency component of a signal for recording. See Pre-Emphasis and De-Emphasis.

A box that holds a loudspeaker(s).

1) In video,. a device, often built into video cameras, that changes individual component signals into composite signals. For example, an encoder combines Y (luminance) and C (chrominance) signals to produce a video image. 2) In audio, a device which creates a matrix encoding of four or more discrete channels into two channels for transmission on standard two-channel audio media. Or a device which takes multiple digital data streams (as in six channel discrete digital surround sound) and compresses them into a single data stream for more efficient storage and transmission. A counterpart decoder performs the opposite function, taking a single encoded bitstream and breaking it into multiple datastreams, or in the case of matrix decoding restoring the original four (or more) channels from the encoded two-channel matrix signal.

Converting to a code. In video, the combination of electronic elements into one signal. For example, converting R, G, and B primary color video signals to hue and saturation in the C signal.

To manipulate information into a coded form that cannot be read without a device that will unscramble the code. Video signals are also scrambled in cable and pay-TV systems so that the viewer must pay to receive the program after it has been electronically deciphered. The DVD DIVX format uses encryption other than the DVD Forum standard. Also known as Scrambling.

See Edge Sharpening.

The time variation of the amplitude of a vibration.

Erasable Programmable Read Only Memory. An IC chip capable of storing software instructions or data and retains that information when power is removed. Erasing is done by exposure to ultraviolet light. New information is loaded into the EPROM using a PROM programmer or PROM burner.

EQ (Equalization)
The adjustment of timbre, or tone quality, achieved by changing the amplitude of a signal at different frequencies, thereby altering the frequency response characteristics. (Abbreviated: EQ.) Tone controls are simple forms of equalization. More complex equalizers incorporate one-third octave equalization, adjustable frequency centers, and bandwidths.

Equal Loudness Contours
A set of curves of equivalent loudness, which model the ear frequency response throughout the audible spectrum. The curves, obtained from actual testing, show how much more sound power is required at one frequency than another to obtain a sound of equal loudness. The results show that the human ear is less sensitive to sound at the extreme high and low frequencies.

A component, or built-in device which allows for constituents of the frequency response to be boosted or attenuated. Each constituent generally corresponds to a frequency band defined by its center value. The better equalizers incorporate one-third octave equalization, adjustable frequency centers, and bandwidths.

Equalizing Pulses
Pulses that cause the vertical deflection to start at the same time in each interval, and also keep the horizontal sweep circuits in step during the portions of the vertical blanking interval immediately preceding and following the vertical sync pulse.

The science of designing machines, tools and computers so that people find them easy and comfortable to use.

Error Correction
The restoration of corrupted or lost digital data through special DSP techniques so that the corrected data is identical to the original. It is typically found in digital playback systems, such as Compact Disc, LaserDisc and DVD players that play PCM digital audio.

Enhanced Video Connector. A VESA standard, 35-pin video graphics card connector that can carry signals for video, audio, 1394 (Firewire) and USB (Universal Serial Bus). This allows the computer monitor to act as a central connection hub.

Exciter Lamp
A light source in the film soundhead that illuminates the area on the optical track to be read into an audio signal.

Expansion Slots
Slots, or spaces, inside a cabinet that are used to connect additional circuit boards (cards).

Extended Play
EP. In LaserDisc players, the CLV mode, which can provide up to one hour of pre-recorded material per disc side. In VHS VCRs, the slowest recording speed, which provides six hours of running time with a T-120 cassette.

External Speaker Jacks
Allows one to attach separate speakers directly to a TV for improved sound quality; or to attach rear speakers to experience surround. The downside to this equation is based on the wattage of the internal television amplifier. Some rear projection models allow one to utilize the set's internal speakers for the center channel.

F Connector
A type of plug used for RF video connections, such as used with TV antennas and cable TV to TV sets and VCRs.

A sound system, designed by RCA for the Disney film Fantasia (1940) to reproduce the spatial attributes of a symphony orchestra. Three optical tracks (left, right, center) were printed on 35mm film and run in sync with the picture. A surround signal was picked up from the main channels and fed to several speakers throughout the theatre.

Frequently Asked Questions. Typically a response in a magazine or web site to people's questions.