As known as “Node Splitting” or “Node Splits”. In HFC networks today there are many hundreds and often more than a thousand homes passed per optical node, which is higher than desirable. To provide high-speed Internet access, an inexhaustible library of VOD choices, eye popping HDTV service, and a wide range of telephony options there should be as few as a hundred homes per optical node. Node segmentation or node splitting is aimed at removing high homes passed (HP) count optical nodes and replacing them with four-port optical nodes in sufficient number to reduce the number of HP to 250 total or less per connected node. Noise
The word “noise” is a carryover from audio practice. Refers to random electrical energy or interference. May produce a “salt-and-pepper” pattern over the picture. Heavy noise is sometimes called “snow.”
Unwanted signal or interference which disturbs the reception of the desired information, often expressed in degrees Kelvin or decibels. [Arr11] Noise Equivalent Power
NEP; the minimum input optical power to generate photocurrent, equal to the RMS noise current in a 1 hertz bandwidth. The related characteristic detectivity (D) is the inverse of NEP, 1/NEP; and the specific detectivity () is the detectivity normalized to the area (A) of the photodetector,. The NEP is roughly the minimum detectable input power of a photodiode. When a photodiode is used in an optical communication system, the parameters responsivity, dark current, and noise equivalent power (NEP) contribute to the sensitivity of the optical receiver, which is the minimum input power required for the receiver to achieve a specified bit error ratio. [Wki11] Noise Figure
A measure of the ability of an amplifier to increase the strength of a signal while adding the minimum possible self-generated noise. It is mathematically equal to ten times the log of the input S/N ratio to the output S/N ratio. Also, the ratio of the actual amount of noise at the input of an amplifier to that which would be generated in an ideal resistor, usually expressed in decibels. The lower the figure, the better the device. [Arr11] Noise Floor
The minimum noise level possible on a system. [Arr11] Noise, Intrinsic
Noise which is normally present in a transmission path or device which is not caused by modulation and which is not affected by input level or system loading. [Arr11] Noise Power Ratio (NPR)
The ratio of the signal power density to the power density of the combined noise and intermodulation distortion in the channel. Essentially, NPR is the depth of notch. The signal power density is defined with the entire passband filled with energy. The power density of the noise and intermodulation distortion shall be measured by removing signal power from a range of frequencies with a notch filter while maintaining constant total signal power at the device under test (DUT) input. Noise Temperature
A measure of the amount of thermal noise present in a system or device. The lower the noise temperature, the better the device. [Arr11] Noise, Thermal
Noise produced by the random motion of free electrons in all electrical conductors. The movement of an electrical charge (electron) through the resistance of the conductor produces a (noise) voltage. Thermal noise is white noise. [Arr11] Nominal Path Loss
The design engineered signal attenuation from point of transmission to point of reception. [Arr11] Nonce
A random value used only once that is sent in a communications protocol exchange to prevent replay attacks. Non-contiguous Channel Assignment
The encompassed spectrum on an RF output port contains gap channels (inactive channels). [Cab11] Non Dispersion-shifted Fiber (NDSF)
The most popular type of single-mode fiber (SMF) deployed. It is designed to have a zero-dispersion wavelength near 1310 nm. [Fib111] Nonlinearity
The deviation from linearity in an electronic circuit, an electro-optic device or a fiber that generates undesired components in a signal. Examples of fiber nonlinearities include SBS, SRS, FWM, SPM, XPM, and Intermodulation. [Fib111] Non Repudiation
The ability to prevent a sender from denying later that he or she sent a message or performed an action. Non Zero-dispersion-shifted Fiber (NZ-DSF)
A dispersion-shifted single-mode fiber that has the zero-dispersion wavelength near the 1550 nm window, but outside the window actually used to transmit signals. This strategy maximizes bandwidth while minimizing fiber nonlinearities. [Fib111] North American ISDN Users Forum (NIUF)
An association of ISDN product manufacturers and telephone company concerns dedicated to setting standards for the implementation of ISDN. They are, among other things, responsible for the formation of the National ISDN-1 standard, standard ISDN Order Codes (like Easy ISDN 1), and ISDN Feature Set Codes. North American Number Plan (NANP)
The body that assigns three digit area codes for the United States, Canada and the Caribbean. Or the method of identifying telephone lines and area codes in the public network of North America.
Numbering Plan Area (more commonly known as area code) NXX (sometimes called exchange) represents the next three numbers of a traditional phone number. The N can be any number from 2-9 and the Xs can be any number. The combination of a phone number's NPA-NXX will usually indicate the physical location of the call device. The exceptions include toll-free numbers and ported numbers (see LNP).
Non-Return-to-Zero; a data transmission method in which the 0s and 1s are represented by different polarities, typically positive for 0 and negative for 1. [Fre11] NTIA
National Telecommunications and Information Administration; a unit of the USA Department of Commerce (DoC) that address U.S. government telecommunications policy, standards setting and radio spectrum allocation. [Sat07]
NTSC composite video signal (source: Composite/CVBS Interface)
A capability that permits telecommunications users to maintain the same telephone access number as they change telecommunication suppliers.
Numerical Aperture (NA)
The light-gathering ability of a fiber; the maximum angle to the fiber axis at which light will be accepted and propagated through the fiber. NA = sin a, where a is the acceptance angle. NA also describes the angular spread of light from a central axis, as in exiting a fiber, emitting from a source, or entering a detector. [Fib111] Nutation Damping
The process of correcting the nutational effects of a spinning satellite which are similar in effect to a wobbling top. Active nutation controls use thruster jets. [Sat07] NVOD Near-Video-on-Demand
Nanowatt; one billionth of a Watt or 10-9 Watts. [Fib111] NWC Net Weekly Circulation Nyquist Frequency
The lowest sampling frequency that can be used for analog-to-digital conversion of a signal without resulting in significant aliasing. Normally, this frequency is at least twice the rate of the highest frequency contained in the signal being sampled. Also called Nyquist rate. [Fib111] NZ-DSF
Optical-to-Electrical converter; a device used to convert optical signals to electrical signals. Also known as OEC. [Fib111] OADM
See optical add/drop multiplexer. [Fib111] OAM
Operation, Administration, and Maintenance; refers to telecommunications networks. [Fib111] OAN
Optical Access Network; a network technology, based on passive optical networks (PONs) that includes an optical switch at the central office (CO), an intelligent optical terminal at the customer’s premises (ONU or ONT), and a passive optical network between the two, allowing services providers to deliver fiber-to-the-home while eliminating the expensive electronics located outside the central office. [Fib111] Object Carousel
An object carousel is a repetitively broadcast file system. Object Identification (OID)
A sequence of integers used to traverse an SNMP managed object tree to find a specific managed object.
The software that provides support for the defined OCAP 1.0 on a host receiver.
One of the Java Application Program Interfaces (APIs) standardized as part of the OCAP 1.0 Specification. For the OCAP 1.0 implementation, the OCAP APIs include the DVB- J APIs that have been modified and/or extended by this specification.
The width of a frequencyband such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage B /2 of the total mean power of a given emission. Unless otherwise specified by the CCIR for the appropriate class of emission, the value of B /2 should be taken as 0.5%. [NTIA1] [RR2] Note 1: The percentage of the total power outside the occupied bandwidth is represented by B. Note 2: In some cases, e.g., multichannelfrequency-division multiplexing systems, use of the 0.5% limits may lead to certain difficulties in the practical application of the definition of occupied and necessary bandwidth; in such cases, a different percentage may prove useful. [NTI11] 1Term names and definitions extracted verbatim from the National Telecommunications and Information Administration(NTIA) Manual of Regulations and Procedures for Federal Radio Frequency Management. [U.S. Government agencies may obtain the NTIA Manual from the NTIA Office of Spectrum Management, Room 1605, Herbert C. Hoover Bldg., 14th and Constitution, N.W., Washington, DC 20230. The NTIA Manual may be purchased by non-Government interests at the U.S. Government Printing Office, Stock No. 903-008-00000-8.]
2Terms and definitions extracted verbatim from the International Telecommunication Union Radio Regulations, Malaga-Torremolinos (Oct. 1984, rev. 1985).