Technical Glossary
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Displaying 50 glossary terms found.

 


V
(1) Vertical (as in RGBHV), or the vertical sync connector on a panel. This is used when the sync is separated into Horizontal and Vertical components. (2) In electrical specifications, "v" is the abbreviation for "volts."

Variable Area
The technical term for the theatrical release print analog optical soundtrack whose width varies with the sound. Developed by RCA. An analog optical soundtrack sometimes is referred to as an SVA track, or "stereo variable area." Another type of optical track, variable density, was tried at an earlier time, which varied in photographic shading with the sound, rather than in width. See Variable Density.

Variable Density
A method of optical sound recording, used by Western Electric, in which the sound track varies in opacity of light in proportion to the time varying changes in the audio signal.

Variable Level Control
This control is a variable voltage level control similar to a contrast control on a data monitor. The level control increases or decreases the levels of red, green and blue simultaneously, thus not affecting the adjusted gray scale of the monitor or projector.

VCR
Generally defined as video cassette recorder. In Europe, however, VCR is a trademark for a particular video format developed by Philips of The Netherlands. See Videocassette Recorder.

Vectorscope
A specialized oscilloscope used in video systems to measure chrominance.

Vertical Blanking
Retrace. The turning off of the scanning electron beam in a CRT during the time the beam must return from the bottom of the screen to the top. Vertical blanking occurs between writing each field of a picture. If vertical blanking does not occur, a diagonal "retrace" line will display from lower right to upper left of the screen. See Retrace.

Vertical Blanking Interval
The blanking time at the beginning of each field. It contains equalizing pulses and vertical sync pulses.

Vertical Dispersion
The dispersion of a loudspeaker in the vertical plane. See Horizontal Dispersion.

Vertical Frequency
The number of vertical fields per second. NTSC = 60 Hz. PAL = 50 Hz.

Vertical Interval
The synchronizing information which is presented between fields, and then signals the picture monitor to return to the top of the screen to start another vertical scan.

Vertical Oscillator
The electronic circuit that creates sawtooth-scanning signals synchronizing with the vertical sync signal for the vertical deflection of the CRT or the pickup tube.

Vertical Resolution
The amount of picture detail that can be perceived vertically. Also known as vertical definition. Vertical resolution is defined as the number of transitions that can occur from the top to the bottom of the picture. Transitions in the vertical direction are represented by horizontal lines. The number of distinct horizontal lines, alternately black and white, that can be seen in a TV image. Vertical resolution is fixed by the number of horizontal lines used in scanning. The maximum limit of vertical resolution in any video system is determined by the number of "active lines" in the video signal or 482 lines that are available for active videoóthe upper limit of vertical resolution in the 525 line system. Vertical resolution can be anywhere from a high of 482 lines to a low of 241 lines, depending on the amount of vertical motion in the picture. See Luminance Picture Resolution.

Vertical Retrace
The return of the electron beam from bottom to top at the end of each field

Vertical Scan Rate
Indicates the rate at which the electron beam moves from the top to the bottom of the screen. Scan rates slower than 48 Hz will exhibit a noticeable flicker in the picture. The European PAL system runs at 50 Hz, the NTSC television system runs at 60 Hz, and many computer displays run at 72 Hz or 75 Hz. The perception of flicker is partially determined by the decay factor of the display device. Generally speaking, 60 Hz is about as fast as you need in CRT based technology to get rid of flicker for the majority of devices. With fast CRTs, it can be necessary to go as high as 72 Hz to insure that flicker is not seen by the majority of viewers.

Vertical Scanning
The vertical movement of the electron beam on the picture tube.

Vertical Shift Or Vertical Centering Control
Adjusting the vertical centering control one way shifts the displayed image toward the bottom of the monitor or projector screen and the other way shifts the displayed image to the top of the monitor or projector screen.

Vertical Sync
The sync pulses that control the vertical scanning of the TV picture. NTSC = 60 Hz. PAL = 50 Hz.

VESA
Video Electronics Standards Association. A nonprofit member organization dedicated to facilitating and promoting personal computer graphics through improved graphics standards for the benefit of the end-user.

VGA
Video Graphics Array. Introduced by IBM in 1987, VGA is an Analog signal with TTL level separate horizontal and vertical sync. The video outputs to a 15-pin, HD connector and has a horizontal scan frequency of 31.5 kHz and vertical frequency of 70 Hz (Mode 1, 2) and 60 Hz (Mode 3). The signal is non-interlaced in modes 1, 2, 3 and interlaced when using the 8514/A card (35.5 kHz, 86 Hz) in mode 4. It has a Pixel by Line resolution of 640 x 480 with a color palette of 16/256,000.

VHF
Very High Frequency. Television broadcast range between 30 MHz and 300 MHz, on channels 2 through 13.

VHS
Video Home System. The videocassette format originated and developed by JVC and adopted by a number of different manufacturers. Not compatible with the Beta format, which is also a videocassette format originated and marketed by Sony, but differs electronically. See Beta.

Video
Video describes picture information, of which our television system is part. It refers generally to any method using video tape, computer, or television technology to produce an image electronically as opposed to on film.

Video (Inputs/Outputs)
The number indicates the number of inputs and the number of outputs on TV sets. Normally there are fewer video outputs. On the other hand, more video (and their audio counterparts) are desirable as it allows more versatility in signal switching of multiple VCRs, LaserDisc players, DVD players, etc. Depending on how one decides to hook-up their A/V system, either the TV or their A/V Receiver/ Processor can be used for video switching. Audio and Video input jacks are more desirable for hooking up a VCR than putting the signal through your RF connector as it will provide better audio and video quality.

Video Amplifier
A low-pass amplifier with a bandwidth of 2-10 MHz, used to strengthen the video signal for TV transmission and reception.

Video Card
A circuit board that is usually mounted inside the computer that generates signals necessary to drive, or control a specific type of monitor.

Video Compression
Term used to describe methods of reducing the data in digital television signals. Allows digital TV to travel though lower-capacity transmission systems, on everything rom cable and digital broadcast TV to DVD. The satellite and cable industry will use video compression to offer hundreds of channels. MPEG-2 video compression is the worldwide standard in the case of DVD. See MPEG.

Video Connector
The connector on the video card or computerís graphics output that is connected to the video input on the local monitor.

Video Converter
See Scan Converter.

Video Disc
See LaserDisc and DVD.

Video Distribution Amplifier
An amplifier for strengthening the video signal so that it can be supplied to a number of video monitors at the same time.

Video Gain
The amplitude of a video signal.

Video Monitor
A high-end display device that produces a picture but does not have a tuner (channel selector) or loudspeaker(s). It must be connected to a video source to display images. Typically used in the professional broadcast and post-production field.

Video Noise Reduction
Special circuitry that helps reduce noise, for example, snow and artifacts in the picture. Video Noise Reduction especially helps reduce video noise in dark picture areas, and helps maintain sharp picture edges in brighter areas.

Video Projector
A device which projects a video image onto a presentation surface.

Video Standards
See NTSC, PAL and SECAM.

Videocassette Recorder
VCR. Video recorder that uses magnetic tape housed in a protective container. Videocassette types for home use are VHS (including Super VHS variation) and Beta (including Extended-Definition Beta and SuperBeta). Formats intended primary for camcorders are 8mm (including Hi-8), Compact VHS (including Super Compact VHS) and Digital VCR.

Videodisc
Term usually refers to laser-optical disc-based video formats (see LaserDisc), though it has been used to refer to now-defunct stylus-read formats such as CED and VHD.

Viewing Filter
A transparent filter that passes a single coloróblue, green or red. Used in conjunction with SMPTE color bars for calibrating a monitorís saturation and hue settings and evaluating its color demodulation circuitry.

Virtual Image
If a converging lens is placed before an object so that the distance between them is less than the distance to the focal point, the image seen of the object will be magnified and will appear right side up. This is called a virtual image. When the distance between lens and object is greater than the focal point, the image will not be magnified and will be upside down. This is called a real image. See Real Image.

Virtual Memory
The process of increasing the apparent size of a computerís random-access memory (RAM) by using a section of the hard disk storage as an extension of RAM.

Vitaphone
A theatrical sound system introduced by Warner Bros. It used the sound-on-disc concept, and launched the era of "talking pictures" in 1927 with The Jazz Singer.

VLB
(Video Loop Back) A feature in some switchers that allows a video signal to exit to another device, such as a decoder or scan-doubler. The output from that device is then used as another input to the switcher.

Volt
The potential difference or electromotive force that will cause current of one ampere to flow through the resistance of one ohm. Symbolized by "v."

Voltage
The potential difference or electromotive force expressed in volts. See Volt

Voltage Surge Suppressor
A device that protects electronic products from a sudden rise of voltage in an electrical circuit.

VTG
Video Test Generator. A device that generates video test patterns at scan rates that simulate most popular applications.

VTR
Video Tape Recorder.

VU
A visual meter indicating the RMS value of a signal. Since the human perception of loudness corresponds to the RMS value of the signal, VU meters indicate volume (VU stands for Volume Units). Zero VU is considered to be standard operating level.

VU Meter
Volume Unit Meter. For sound systems or recorders, a device to indicate the relative levels of the various sounds being recorded or played. Usually calibrated to show a maximum recording level to avoid tape saturation and distortion.