Glossary - R
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Radio Frequency (RF) - Analog electrical signals sent over the cable. Conventional (broadcast) television and radio, as well as cable TV, deliver RF signals to your television/radio. RF is quickly becoming yesterday's news to many cable TV providers who are installing fiber-optic lines that will replace today's cables.
Ranging - The process by which a cable modem learns its distance from the headend. Ranging is a continual process, due to the expansion and contraction of cable that occurs during the day.
Reboot - The act of reloading the operating system of a computer, usually by resetting the power to the computer with the power switch, or selecting Start/Shutdown/Restart in Windows.
Rebuild - The physical upgrade of a cable system, often involving the replacement of amplifiers, power supplies, passive devices and sometimes the cable, strand, hardware and subscriber unit.
Receiver - Electronic device which can convert electromagnetic waves into either visual or aural signals, or both. For cable television, usually the subscriber's television set.
Reflections or Echoes - In video transmission this may refer either to a signal or to the picture produced. In a signal it is either waves reflected from structures or other objects or waves which are the result of impedance or other irregularities in the transmission medium. In a picture, "Echoes" observed in the picture produced by the reflected waves.
Regional Bell Operating Company (RBOC) - RBOC comprises the U.S. local carriers created in the 1982 Consent Degree to break up AT&T. Seven were formed to serve as parent companies for the 22 then-existing Bell Operating Companies.
Repeater - A repeater is a network device that repeats signals from one cable onto one or more other cables, while restoring signal timing and waveforms.
Resistance - The opposition that a substance offers to the flow of electric current.
Resistor - An electronic component that is deliberately designed to have a specific amount of resistance.
Resolution - A measure of picture resolving capabilities of a television system determined primarily by bandwidth, scan rates and aspect ratio. Relates to fineness and details perceived.
Resolution (Horizontal) - The amount of resolvable detail in the horizontal direction in a picture. It is usually expressed as the number of distinct vertical lines, alternately black and white which can be seen in three-quarters of the width of the picture. This information usually is derived by observation of the vertical wedge of a test pattern. A picture which is sharp and clear and shows small details has good, or high, resolution. If the picture is soft and blurred and small details are indistinct it has poor, or low, resolution. Horizontal resolution depends upon the high-frequency amplitude and phase response of the pickup equipment, the transmission medium and the picture monitor, as well as the size of the scanning spots.
Resolution (Vertical) - The amount of resolvable detail in the vertical direction of a picture. It is usually expressed as the number of distinct horizontal lines, alternately black and white, which can be seen in a test pattern. Vertical resolution is primarily fixed by the number of horizontal scanning lines per frame. Beyond this, vertical resolution depends on the size and shape of the scanning spots of the pickup equipment and picture monitor and does not depend upon the high-frequency response or bandwidth of the transmission medium or picture monitor.
Response Time - The length of time between the occurrence of an event and the response of an instrument or circuit to that event.
Return Path - The term used to describe traffic and paths that go from the subscriber to the headend. Also known as Upstream, or Reverse Path.
Reverse Channel - The direction of signal flow toward the headend, away from the subscriber; equivalent to upstream.
Reverse Path Forwarding - A technique where a router receives a packet, then floods the packet out on all paths, except the path on which it received the packet.
R-F Pattern - A term sometimes applied to describe a fine herringbone pattern in a picture. May also cause a slight horizontal displacement of scanning lines resulting in a rough or ragged vertical edge of the picture. Caused by high-frequency interference.
Right-Click - Using the secondary mouse button (usually the right button) to open context menus.
Roadblocking - The practice of stripping commercials in designated time periods across multiple cable channels. Can be an effective method for catching channel surfers.
Router - Routers are special network devices used to connect one recognized computer network to another. Routers work like a postal worker; they examine the To addresses of network messages they are given and use part of the address like a zip code to figure out which computer network to send it to. Once a router has figured out which network the message should go to, it sends the message to another router, which repeats the process until the last router in the chain sends it directly to the computer listed in the destination address. Most WANs use routers to connect one LAN location to another.
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