An amplifier has a maximum amount of available gain. When designing a network, amplifiers are specified to supply this maximum amount of gain, less some amount of reserve gain. This reserve can be used to accommodate signal level variations that can occur during installations. [Arr11]
A resident application is an application that is saved on the host device and may be run at any time. Resident applications, such as the monitor application or EPG, are typically responsible for host device control.
A part of the Access Network which adds network functionality and multiplexes different services. The gateway must perform the basic functions of media translation and address translation.
The loss of the attenuator at the minimum setting of the attenuator. [Fib111]
The opposition that a substance offers to the flow of electric current. In DC circuits, the opposition a material offers to current measured in ohms; in AC circuits, resistance is the real component of impedance and may be higher than the value measured at DC. [Arr11]
An electronic component that is deliberately designed to have a specific amount of resistance.
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.
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.
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.
Resource reSerVation Protocol (RSVP)
An Internet protocol used for negotiating end-to-end IP quality of service (QoS) within the network. In a PacketCable-based network, RSVP can be used to negotiate QoS on the cable access network. Or IETF resource reservation setup protocol for IP networks.
The fidelity with which the output of a system, device, or network corresponds to its input. [Arr11]
The ratio of generated photocurrent to incident light power, typically expressed in Amperes per Watt (A/W) when used in photoconductive mode. The responsivity may also be expressed as a Quantum efficiency, or the ratio of the number of photogenerated carriers to incident photons and thus a unitless quantity. [Wki11]
Graph of Responsivity of a Silicon Die Based Photodiode versus Optical Wavelength courtesy of Wikipedia, http://en.wikipedia.org/wiki/Photodiode
The length of time between the occurrence of an event and the response of an instrument or circuit to that event.
A return channel refers to the communications mechanism that provides connection between OpenCable and a remote server.
The parameter describing the attenuation of a guided wave signal (e.g., via a coaxial cable) returned to a source by a device or medium resulting from reflections of the signal generated by the source. Also, the ratio of optical power launched into an input port to the optical power returning to the same input port. Both directivity and return loss are expressed as positive dB and are measured with all output ports optically terminated. [AOF11]
The term used to describe traffic and paths that go from the subscriber to the headend. Also known as Upstream, or Reverse Path.
Return Path Optical Receiver (RPOR)
Converts optical wavelengths to RF for distribution of quad-play HFC network content (voice, video, data, cellular) within a cable or telco network headend, hub, or central office (CO).
HFC Return Path System Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/r
Return Path Optical Receiver, RPOR, Photograph courtesy of Aurora Networks
Return To Zero (RZ)