Technical Glossary
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Displaying 56 glossary terms found.


Tangential Mode
See Mode.

The disintegration of a picture into diagonal stripes, due to loss of horizontal synchronization.

An electronic system in which film frames are transferred to video. The video used in virtually all telecine operations today is digital, either NTSC/PAL or HD (high definition). The telecine converter turns the movie industry’s standard of 24 frames per second to the video industry’s standard of 30 frames per second by repeating portions of certain frames.

An electronic method of transmitting information from one location to another over a telephone network.

A meeting of geographically separated people who may have two-way audio, video, and text communications often via telephone and/or closed-circuit television.

The technical equipment and events involved in creating television productions. The picture portion of a television broadcast.

Television Receiver

A device typically having a keyboard and display that is capable of sending text to and receiving text from another device, a network, etc.

A load, or impedance at the end of a cable or signal line used to match the impedance of the equipment that generated the signal. The impedance absorbs signal energy to prevent signal reflections from going back toward the source. In the video industry, termination impedance is typically 75 ohms.

A device that provides termination for a signal line, or several signal lines, at the end of a cable. Usually a close-tolerance resistor for each signal, a terminator is often mounted in its own connector, making it easy to install.

Total Harmonic Distortion. The noise in an audio signal comprising of multiples of a sound’s fundamental frequencies. THD is expressed as a percentage of the output signal.

Threshold Of Hearing
The minimum sound pressure level of a pure tone that can be perceived by a person with good hearing. A sound pressure of 20x10-6 pascals is defined as 0dB SPL.

Threshold Of Pain
The minimum sound pressure level of a pure tone which causes a sensation of pain in the ear. (At approximately 140 dB SPL)

The distance from projector lens to screen.

A trademark licensed to movie theatres and manufacturers of home theatre products, identifying compliance with the performance parameters of Lucasfilm Ltd. for commercial and home theatre sound systems. THX is a set of technologies first developed for the cinema and subsequently for the home. In the theatre, THX standardizes the sonic environment by stipulating not only the acoustics required, but the playback equipment as well. The objective is to maintain a consistency in sound quality from dubbing stage to cinema or home theatre so that the listener experiences movie sound the way filmmakers envisioned it for a movie theatre. For professional applications, strict adherence is made to theatre acoustics, approved playback equipment, and noise levels. In the home theatre, THX-certified amplifiers, loudspeakers, and processors meet stringent minimum THX performance specifications. THX does not focus on soundtrack formats and processes. THX develops standards for the playback environment, regardless of film format. THX-certified theatres use professional Dolby, DTS and SDDS processors for playing soundtracks (which is why the THX logo can appear with others on the same theatre marquee), and all THX-licensed home theatre systems are based on Dolby ProLogic matrix surround decoding. THX also is known for its Theatre Alignment Program (TAP) and Digital Mastering for home video (DVD, LaserDisc and VHS).

THX® Crossover
An active crossover network, based on the Linkwitz-Riley design, for the stage loudspeakers in a professional THX sound system. It serves to optimize the transition between the frequencies reproduced by the bass module and those from the midrange-high frequency horn. The THX crossover also includes time alignment between the bass and treble drivers, and high frequency equalization.

A descriptive rather than technical term usually applied to a well defined sound notable for its clarity and distinction. "Tight" usually refers to the absence of excessive reverberation and out of phase reflections.

Geometric distortion in which lines that are supposed to be vertical or horizontal aren’t. Also called Skew.

The subjective tonal quality of a sound. The timbre of any musical or non-musical sound is determined largely by the harmonic structure of the sound wave. Rich sounding musical tones tend to have a great number of inner harmonics which contribute to their lush timbre, while thin sounding musical tones tend to be lacking in the presence of harmonics.

Timbre Matching
A type of equalization applied to the surround channels in home THX® processors based on a finding that loudspeakers used for the surround are different in design (dipole vs. director radiator) in THX-certified systems and tend to be closer than those for the front, and therefore sound brighter. This equalization compensates for this perceived effect.

Time Alignment
1) The degree in which the sounds from separate drivers in a loudspeaker system reach the listener’s ears in perfect synchrony. 2) In multichannel systems, the process of temporally matching speakers. This is specified in the home THX requirements for 5.1 channel reproduction, but is not exclusive to THX and was applied prior to THX adoption as part of their specifications. Appropriate time delays are applied to each channel so that a realistic three-dimensional soundfield is achieved by all speakers acting coherently.

Time Base Corrector
VTR (Video Tape Recorder) playback circuitry used to smooth out the wavering edges of a video image.

Time Base Error
Slight errors in the line-to-line position of video information which occur between recording and playback. At the time of playback, these appear as serrations, tending to make the edges of the image waver.

Time Base Generator
A sync generator which puts a clock signal on the video tape to refer to for precise horizontal lock-up of an image.

Time Code
A digital or binary code used to label each frame of a video signal. This is very useful for editing the video since the time code is in the form of hours, minutes, seconds and frames.

Time Coherent
Time aligned.

Time Delay
Audio circuitry that accepts input signal and provides a delay in time before initiating an output signal.

A relative measure of the amount of white in a given color. See Hue.

Tint Control
This control sets the type of color or the Hue or Tint of the picture. It will often have the range to take flesh tones from green, through magenta.

Titanium Dioxide -
TiO2. A screen coating which renders screens highly reflective.

A theatrical sound system, premiering in 1955 (Oklahoma!) to accompany the wide 70mm picture. Six channels, five for the screen and one for surround, were recorded on 35mm magnetic film and run in interlock with the projector. Later magnetic stripes on the 70 mm print were used instead of the full-coat magnetic film stock.

To switch over to an alternate state from on to off, for example.

Toggle Switch
An electronically charged circuit holding either of two states on or off, for example. The state does not change until the circuit is directed to the alternate state.

A type of fiber optic digital connection jack for consumer audio, developed by Toshiba.

Total Harmonic Distortion
See THD.

Touch Panel
A control panel with a flat surface (usually marked off) that functions as switches or controls. May also be called "touch screen."

Touch Screen
A control panel with a flat surface (usually marked off) that functions as switches or controls.

The apparent positioning (imaging) of movie sound effects that match their on screen positions.

Device (microphone, tape head, loudspeaker) that converts on e type of energy (electrical, acoustical, magnetical, mechanical) into another.

A momentary peak or burst in program material. Transients are not registered by VU meters, because of their fleeting nature, but are nevertheless capable of producing overload distortion.

Transient Response
The ability of a speaker system or audio component to reproduce fleeting, momentary, dynamic level changes.

Active semiconductor with three or more electrodes.

The propagation of sound through a medium or barrier. See Sound Transmission.

Transmission Co-Efficient
The portion of sound energy transmitted through a material. A barrier of transmission co-efficient "t" will actually have a transmission loss of -10 log t.

Transmission Loss
TL. The number of dB by which a barrier reduces the transmission of sound. If a 100 dB(spl) amplified guitar on one side of a wall was measured to produce only 40 dB(spl) on the other side of the same wall, the TL of the wall would be denoted as 60 dB. Transmission loss varies markedly with frequency, and therefore should be indicated at several frequencies for a given barrier, if an accurate representation of soundproofing ability is to be given.

A device that can change sound waves into electric waves or impulses to send to a receiver.

The highest frequencies in the audio spectrum, above 1.3 kHz and usually with an upper limit of 20 kHz.

A surround loudspeaker (trademarked by M&K Sound Corporation), which combines both a direct radiator and a dipole in the same cabinet. See Direct Radiator and Dipole.

Transistor To Transistor Logic. Digital type signal, usually 4-5 volts peak-to-peak. Distance limitation is 6-10 feet. Signal splitting is acceptable. TTL signals are either "ON" or "OFF" and is characteristic of low resolution computers (CGA/EGA).

Portion of a TV that selects the channel or station. Also called Channel Selector.

To adjust or fine-tune.

A tiny screwdriver for making sensitive adjustments to audio visual and computer equipment.

High-frequency (treble) loudspeaker driver.

Twin Lead
Standard TV 300 ohm flat antenna wire not shielded against electrical interference (ribbon lead).

Twitter is a variation of Flicker (sometimes called interline flicker). It is most annoying when one is just a little too close to the TV display. That is, where one can still barely discern the scan line structure. Twitter occurs when a single white line is shown during field one, a sixtieth of a second later a second white line appears just below the first line on the raster. Each line is refreshed at a 30 Hz rate so each flickers separately. Because the lines are alternately refreshed in different fields, a sixtieth of a second apart in time, the two bright lines will seem to be one line that twitches up and down. See Flicker.

Tuner PIP - Two built-in TV tuners allow the viewing of two programs without a second video source. See PIP.