V Terms
Variable Bit Rate: Operation where the bit rate varies with
time during the decoding of a compressed bit stream.
VBI: Vertical Blanking Interval: Used for vertical synchronization
between television field transmission, during which the picture forming beam
returns from the bottom to the top of the picture. Can be used to carry data
in addition to the normal TV signal.
VDT: Video dial tone: Refers to telephone service category
in which LEC provides common carrier broadband subscriber loops capable of
delivering video signals.
Velocity of Speed of signal transmission:. In free space,
electromagnetic waves travel at the Propagation speed of light. In coaxial
cables, this speed is reduced due to the dielectric material. Commonly expressed
as percentage of the speed in free space.
Vestigial Sideband: A system of transmission wherein the sideband
on one side of the carrier is Transmission transmitted only in part.
VFS: Video File Server; A system that delivers multiple video
delivery over a network. The system must allow random access to some or all
of the material stored on the system and must permit multiple simultaneous
access to the same piece of material if requested.
VL: bus A computer bus that increases the speed of the bus
used in 486 computers. It was originally intended to speed up graphics but
VL-bus controllers could also accelerate disk performance.
VLC: Variable length coding: A reversible procedure for coding
that assigns shorter code-words to frequent events and longer code-words
to less frequent events.
VLSI: Very large scale integration.
VME bus: High speed parallel backplane system bus originally
developed by Motorola. It is now widely used on technical workstations and
small multi-user systems.
VOD: Video on demand: A service which allows a user to view
whatever program they want whenever they want it with VCR-like control capability
such as pause, fast forward, and rewind.
VR: Virtual reality. Computer generated images and audio which
are experienced through high-tech display and sensor systems and whose imagery
is under the control of 'viewer.
VSBIAM: Vestigial Sideband AM: Amplitude modulation generates
an upper and a lower sideband. To save spectrum space, most of the lower
sideband in a TV signal is filtered out. The remaining, lower or vestigial,
sidebands (approximately 1.75MHz) are kept to avoid impairment of the television
signal.
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