CCTV Glossary
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is related to the contrast of the video image.
Video equalization corrector (video equalizer). - A device that corrects for unequal frequency
losses and/or phase errors in the transmission of a video signal.
Video framestore. - A device that enables digital storage of one or more images for steady display
on a video monitor.
Video in-line amplifier. - A device providing amplification of a video signal.
Video matrix switcher (VMS). - A device for switching more than one camera, VCR, video printer
and similar to more than one monitor, VCR, video printer and similar. Much more complex and
more powerful than video switchers.
Video monitor. - A device for converting a video signal into an image.
Video printer. - A device for converting a video signal to a hard copy printout. It could be a
monochrome (B/W) or color. They come in different format sizes. Special paper is needed.
Video signal. - An electrical signal containing all of the elements of the image produced by a
camera or any other source of video information.
Video switcher. - A device for switching more than one camera to one or more monitors manually,
automatically or upon receipt of an alarm condition.
VITS. - Video insertion test signals. Specially shaped electronic signals inserted in the invisible
lines (in the case of PAL, lines 17, 18, 330 and 331) that determine the quality of reception.
Video wall. - A video wall is a large screen made up of several monitors placed close to one
another, so when viewed from a distance, they form a large video screen or wall.
VOD. - Video on Demand. A service that allows users to view whatever program they want
whenever they want it with VCR-like control capability such as pause, fast forward and rewind.
VHF. - Very high frequency. A signal encompassing frequencies between 30 and 300 MHz. In
television, VHF band I uses frequencies between 45 MHz and 67 MHz, and between 180 MHz and
215 MHz for Band III. Band II is reserved for FM radio from 88 MHz to 108 MHz.
VHS. - Video home system. As proposed by JVC, a video recording format used most often in
homes but also in CCTV. Its limitations include the speed of recording, the magnetic tapes used
and the color separation technique. Most of the CCTV equipment today supersedes VHS
resolution.
VLF. - Very low frequency. Refers to the frequencies in the band between 10 and 30 kHz.
VMD. - Video motion detector. A detection device generating an alarm condition in response to a
change in the video signal, usually motion, but it can also be change in light. Very practical in
CCTV as the VMD analyzes exactly what the camera sees, i.e., there are no blind spots.
VR. - Virtual Reality. Computer-generated images and audio that are experienced through high-
tech display and sensor systems and whose imagery is under the control of a viewer.
VS. - Vertical sync.
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