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.