CCTV Glossary
Cascadia Video Products LLC
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Digital disc recorder - A system that allows recording of video images on a digital disc.
Digital signal - An electronic signal where every different value from the real-life excitation (sound,
light) has a different value of binary combinations (words) that represent the analog signal.
DIN - Deutsche Industrie-Normen. Germany’s standard.
Disk - A flat circular plate, coated with a magnetic material, on which data may be stored by
selective magnetization of portions of the surface. May be a flexible, floppy disc or rigid hard disk.
It could also be a plastic compact disc (CD) or digital video disc (DVD).
Distortion - Nonproportional representation of an original.
DMD - Digital micro-mirror device. A new video projection technology that uses chips with a large
number of miniature mirrors, whose projection angle can be controlled with digital precision.
DOS - Disk operating system. A software package that makes a computer work with its hardware
devices such as hard drive, floppy drive, screen, keyboard, etc.
Dot pitch - The distance in millimeters between individual dots on a monitor screen. The smaller
the dot pitch the better, since it allows for more dots to be displayed and better resolution. The
dot pitch defines the reaslution of a monitor. A high-resolution CCTV or computer monitor would
have a dot pitch of less than 0.3 mm.
Drop-fram Time Code - SMPTE time code format that continuously counts 30 frames per second,
but drops two frames from the count every minute except for every tenth minute (drops 108 frames
every hour) to maintain synchronization of time code with clock time. This is necessary because
the actual frame rate of NTSC video is 29.94 frames per second rather than an even 30 frames.
DSP - Digital signal processing. It usually refers to the electronic circuit section of a device
capable of processing digital signals.
Dubbing - Transcribing from one recording medium to another.
Duplex - A communication system that carries information in both direction is called a duplex
system. In CCTV, duplex is often used to describe the type of multiplexer that can perform two
functions simultaneously, recording in multiplex mode and playback in multiplex mode. It can also
refer to duplex communication between a matrix switcher and a PTZ site driver, for example.
DV-Mini - Mini digital video. A new format for audio and video recording on small camcorders,
adopted by the majority of camcorder manufacturers. Video and sound are recorded in a digital
format on a small cassette (66×48×12 mm), superseding S-VHS and Hi 8 quality.
D-VHS - A new standard proposed by JVC for recording digital signals on a VHS video recorder.
DVR – Digital Video Recorder,
Dynamic range - The difference between the smallest amount and the largest amount that a
system can represent.
(8 strony)
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