CCTV Glossary
Cascadia Video Products LLC
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R
Radio frequency (RF). - A term used to describe incoming radio signals to a receiver or outgoing
signals from a radio transmitter (above 150 Hz). Even though they are not properly radio signals,
TV signals are included in this category.
RAM. - Random access memory. Electronic chips, usually known as memory, holding digital
information while there is power applied to it. Its capacity is measured in kilobytes. This is the
computer’s work area.
RAID. - Redundant arrays of independent disks. This a technology of connecting a number of hard
drives into one mass storage device, which can be used, among other things, for digital recording
of video images.
Random interlace. - In a camera that has a free-running horizontal sync as opposed to a 2:1
interlace type that has the sync locked and therefore has both fields in a frame interlocked together
accurately.
Registration. - An adjustment associated with color sets and projection TV’s to ensure that the
electron beams of the three primary colors of the phosphor screen are hitting the proper color
dots/stripes.
Resolution. - A measure of the ability of a camera or television system to reproduce detail. The
number of picture elements that can be reproduced with good definition.
Retrace. - The return of the electron beam in a CRT to the starting point after scanning. During
retrace, the beam is typically turned off. All of the sync information is placed in this invisible portion
of the video signal. May refer to retrace after each horizontal line or after each vertical scan (field).
Remote control. - A transmitting and receiving of signals for controlling remote devices such as
pan and tilt units, lens functions, wash and wipe control and similar.
RETMA. - Former name of the EIA association. Some older video test charts carry the name
RETMA Chart.
RF signal. - Radio frequency signal that belongs to the region up to 300 GHz.
RG-11. - A video coaxial cable with 75-W impedance and much thicker diameter than the popular
RG-59 (of approximately 12 mm). With RG-11 much longer distances can be achieved (at least
twice the RG-59), but it is more expensive and harder to work with.
RG-58. A coaxial cable designed with 50-W impedance; therefore, not suitable for CCTV. Very
similar to
RG-59, only slightly thinner.
RG-59. A type of coaxial cable that is most common in use in small to medium-size CCTV systems.
It is designed with an impedance of 75-W. It has an outer diameter of around 6 mm and it is a good
compromise between maximum distances achievable (up to 300 m for monochrome signal and
250 m for color) and good transmission.
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