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Dictionary of Technical Terms - T
A B
C D E F G
H I J K L
M N O P Q
R S T U V W
X Y Z
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In telecommunications, the paired cable used to
transport DS1 service.
Test access port. In telecommunications, an MML
command that allows any port on a digital switch to be used as a
test port.
1. Direct, immediate switching from one source to
another, occurring during the vertical interval for clean
transitions. 2. The control panel operation which brings a preset
source or sources to air.
1. A lamp which lights to indicate that the
associated video source is in use. Typical locations of tally lamps
are on the front of video cameras and in the crosspoint pushbuttons
of video switchers. 2. The acknowledgment returned to the control
panel or terminal that an operation has been executed.
A relay whose contacts close when an associated
function is placed on-air. Tally relays are used in video switchers
to provide the customer a way to light a camera tally lamp when the
camera is placed on air at the switcher panel.
In digital picture manipulators, the axes of the
monitor screen.
Time base corrector.
Tension, continuity & bias.
Temperature compensated crystal oscillator.
Technical director. Switcher operator.
Time division multiplex. The management of multiple
signals on one channel by alternately sending portions of each
signal and assigning each portion to particular blocks of time.
A lateral displacement of the video lines due to
sync instability. Visually it appears as though parts of the images
have been torn away.
The operator of the video production switcher in a
live broadcast.
A device for capturing movie film as a video
signal.
Electronically-linked meeting conducted among groups
in separate geographic locations.
Text shown on a television monitor to assist a
performer or speaker.
A defect in a video picture that occurs when the
image being sampled moves too fast for the sampling rate. A common
example occurs when the rapidly rotating spokes of a wagon's wheels
appear to rotate backwards because of video scanning that moves
more slowly than the spokes.
A Grass Valley 10 x 1 compact video/audio routing
switcher.
A Grass Valley Group one rack unit router with 10
inputs and 20 outputs.
In key frame effects, the controls for moving an
object along a path. Tension controls the length of the tension
vector, continuity controls the angle of the path, and bias
controls whether the path will be "pulled" towards the previous or
the following key frame.
An insulating base equipped with one or more
terminal connectors.
Equipment at an end of communication lines that send
and/or receive certain signals for specific services. Some examples
in television include sync pulse generators, processing amplifiers,
and distribution amplifiers.
To complete a circuit by connecting a resistive load
to it. A video termination is typically a male BNC connector which
contains a 75 ohm resistive load. When there are looping inputs,
any unused looping input must be terminated in 75 ohms to ensure
proper signal levels and to minimize reflections.
A transmission line ending in a resistance equal to
the characteristic impedance of the line so that there are no
reflections or standing waves.
Typically a post in a circuit that can be monitored
to test a parameter of the circuit.
An electronic signal with standard characteristics
used to test the capability of circuits.
Device that generates special television signals
used for aligning television equipment.
The ability of a digital picture manipulator to
create textured surfaces that can be applied to shapes.
See total harmonic distortion.
A film pattern made by applying conductive and
insulating materials to a ceramic substrate by a silk-screen
process. Thick films can be used to form conductors, resistors, and
capacitors.
In telecommunications, the minimum forward current
for which the laser is in a lasing state at a specified
temperature.
A measure of efficiency of a system; the rate at
which the system can handle work.
A link from the output of one routing matrix to the input of another
matrix.
time base corrector
Device used to correct for time base errors and stabilize the timing of
the video output from a tape machine.
time base error
Horizontal rate flutter of a video signal caused by tape stretch and
inherent imperfections in the tape transport mechanism of a videotape
recorder.
time code
Timing code laid down on video-tape to give each frame a unique number so
as to ensure exact transitions during editing.
time delay
The time required for a signal to travel through a circuit.
timed
The devices or signals in question are synchronized with one another.
timeline
1. An effects control feature that enables the operator of a switcher or
digital picture manipulator to preprogram a series of timed events, such
as auto transitions, E-MEM recalls, and GPI triggers, and then replay
them. 2. A window within a video editing application where clips and other
production elements can be graphically arranged to create a fully edited
production. The horizontal axis of the timeline window represents a
timeline of the show.
time-multiplex
In the case of ITU-R BT.601-2 (CCIR-601), a technique for transmitting
three signals at the same time on a group of parallel wires (parallel
cable).
timing pulse
See sync pulse.
timing scatter
Routing switcher term describing varying electrical lengths.
title
A caption.
title inserter
See title key.
title key
A key effect which imposes a caption over a background scene. The source
of the title key signal may be a character generator or a graphics camera.
toggle
To change back and forth between two states (for instance: on, off, on,
off, etc.) by alternately opening and closing an electric circuit.
tone
Typically refers to a single-frequency audio signal used as a level
setting reference.
total harmonic distortion (THD)
The ratio of the sum of the ampli-tudes of all signals harmonically
re-lated to the fundamental and the amplitude of the fundamental signal.
T-pulse
A sine-squared pulse used as an indication of frequency and phase
response.
T-pulse to bar
A specification term relating to frequency response of video equipment. A
video signal containing equal amplitude T-pulse and bar portions is passed
through the equipment and the relative amplitudes of the T-pulse and bar
are measured at the output. A loss of response is indicated when one
portion of the signal is lower in amplitude than the other.
trace
In telecommunications, an MML command to trace designated ports.
TRACE™
A GVG trademarked editor program that reads the EDLs from several
generations of edits to a show and constructs a final EDL with references
back to the original source back to the original source show will be
recorded from the original source material, ensuring against
multigenerational degradation.
track
1. The section of a videotape where a particular signal is recorded.
There are separate tracks for video, audio, time code, etc. 2. Levels in
the timeline window of an editing application where video and audio
elements can be placed to insert them into the production.
trail
A digital picture manipulator effect in which an image repeats on screen
as it moves so that it appears to leave a trail of duplicate images behind
it. If the trail is set to decay mode, the trailing images gradually fade
away.
trailing edge
The transition of a pulse that occurs last, such as the high-to-low
transition of a high clock pulse.
transcoder
A device that converts one form of encoded video to another, e.g., to
convert NTSC video to PAL. Sometimes mistakenly used to mean translator.
transducer
A device that converts one form of energy into another. For example, in
fiber optics, a device that converts light signals into electrical
signals.
transform, transformation
In digital picture manipulators, to digitally change a picture in some
way that alters the appearance or location of the picture, such as
applying translation, rotation, perspective changes, size changes, aspect
and skew manipulations, etc.
transformation path
In digital picture manipulators, the path or direction and speed that a
transformed image follows as it moves from one key frame to the next.
transformer
An electrical device that inductively transfers electrical energy from
one circuit to another circuit at the same frequency but usually at a
different impedance, voltage, and current.
transient
A momentary surge on a signal or power line.
transistor
A semiconductor electronic device having three electrodes and used for
signal buffering, amplification, etc.
transition
A change from one picture to another. A transition can be a wipe, mix, or
cut.
transition interrupt
Selection of a new preset source with a transition in progress. The
switcher removes the old program video in time and remains (if necessary)
in black/silent until a newly selected source is ready and placed on-air.
transition status display
A patented GVG device that keys MASTER-21™ status into an
external television monitor.
translate
1. In digital picture manipulators, movement of the image or screen along
its X,Y, or Z axis. 2. Changing a video signal from one format to another.
translator
A device used to convert from one component set to another, e.g., to
convert Y, R-Y, B-Y signals to RGB signals.
transmitter
Equipment used to generate and amplify an RF carrier signal, modulate
this carrier with information, and radiate the modulated RF carrier into
space.
tray (frame)
The metal cabinet that holds circuit boards.
triaxial
A special form of coaxial cable containing three conductors.
trigger
A pulse that starts an action or function.
trim
1. To make a fine adjustment in a circuit or a circuit element. 2. In
video editing systems, to add or subtract time code to adjust edit points.
Trompeter
Brand of connector. Also a brand of tool for plugging and unplugging BNC
connectors.
trough
Also called cable trough. A slot underneath the flooring of a television
facility where cables are laid for running from room to room.
TRS
Timing reference signals in composite digital systems (four words long).
TRS-ID
Timing reference signal identifica-tion. A four-word reference signal
used to maintain timing in composite digital systems.
truncation
Deletion of lower significant bits on a digital system. Usually results
in digital noise.
T-Span
A telephone circuit.
tumble
A transformation in which the picture appears to turn around its X
(horizontal) axis. See also flip.
tuned-circuit equalizer
A circuit that is adjusted to be resonant at a particular frequency.
Equalizer that employs circuits consisting of inductance and capacitance
that can be adjusted for resonance at the desired frequency.
twisted pair
A cable composed of two small insulated conductors twisted together.
Since both wires have nearly equal exposure to any interference, the
differential noise is slight.
TWX
Teletypewriter exchange service.
TypeDeko™
A GVG broadcast quality character generator running under Windows NT on
the DEC Alpha workstation.
Copyright © 2001 Grass Valley Group -
[email protected]
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