Conrad L. Young’s Wired Broadband and Related Industry Glossary of Terms with Acronyms As of 15 February 2012 Open Access This document is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial



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Coring/Stripping Tool

A tool which strips aluminum sheathed coaxial cable and cores the dielectric foam, leaving the cable prepared to accept a connector. (Arris Glossary of Terms)

CoS
Class of Service

Counter-Rotating

An arrangement whereby two signal paths, one in each direction, exist in a ring topology. (FiberOpticsInfo)

c:\users\cyoung\desktop\glossary of terms\drawings_diagrams\counter-rotating.gif

Counter-Rotating Signal Path Illustration courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/c


Couplers

In fiber optics, a device which links three or more fibers, providing two or more paths for the transmission signal. In an "active" coupler, a switching mechanism selects among several routes; in a "passive" coupler, routing is determined by the geometry of the device. (Arris Glossary of Terms) An optical device that combines or splits power from optical fibers. (FiberOpticsInfo)

c:\users\cyoung\desktop\glossary of terms\drawings_diagrams\coupler_fusedcoup.gif

Fused Coupler Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/c


Coupling Ratio
Coupling ratio or splitting ratio is defined as the ratio of the optical power from one output port of the coupler to the sum of the total power from all output ports. The coupling ratio is measured at the specified center wavelength and is normally expressed as a percentage.
(AOFR) The ratio/loss of optical power from one output port to the total output power, expressed as a percent. For a 1 x 2 Wave Division Multiplex (WDM) or coupler with output powers O1 and O2, and Oi representing both output powers:

CR (%) = (Oi/ (O1 + O2)) x 100% and
CR (%) = -10·Log10 (Oi/ (O1 + O2)).
(FiberOpticsInfo)
CP
Content Protection/Copy Protection

CPB

Continuous Power Bus. Provides downstream power and RF signal with tap faceplate removed. (Arris Glossary of Terms)



CPD
Common Path Distortion

CPE
Customer Premises Equipment

CPE Controlled Cable Modem
A cable modem in which a portion of the higher-layer processing is performed by an external device, in particular, by a PC.

CPPI

100 Gbps Parallel Physical Interface; the “C” usually denotes 100 Gbps nominal data rate. (Traverso)
CRA
Certificate Requesting Authority

Crash Point

A term used to describe the RF output produced by an amplifier or other active component that correlates to a level where the predicted linear performance models for multi-carrier distortion parameters composite second order (CSO), composite triple beat (CTB), and cross modulation (XMOD) described below are no longer valid. At or beyond the crash point any additional increase in RF power output level results in increased levels of non-linearity, as measured by CSO, CTB, and XMOD, that are worse than predicted by the mathematical relationships described below.
A one (1) dB change of the output of an amplifier changes CSO by 1 dB.
A one (1) dB change of the output of an amplifier changes the CTB ratio by 2 dB.
A one (1) dB change of the output of an amplifier changes the cross modulation (XMOD) by 2 dB. (Blonder Tongue Laboratories)
The above assumes a channel loading consisting of more than one-third (1/3) analog carriers with the remaining transmitted spectrum consisting of digital content.
In environments where the channel loading is approximately greater than two-thirds (2/3) transmitted content the crash point of an active component, module, or device may be determined and described using a set of measured criteria as described below:


Measured Criteria:

Units:

Threshold BELOW Crash Point:

Threshold ABOVE Crash Point:

Composite Carrier-to-Noise (CCNR)

dB

48

48

Modulation Error Ratio (MER)*

dB

38

38

Bit Error Rate (BER)

Nerr/Nbits

1E-06

1E-06

Under predominantly digital channel loading an active device’s crash point may be identified when one or more of the measured criteria above have exceeded pre-set limits.
CRC
Cyclic Redundancy Check; an error-detection scheme that (a) uses parity bits generated by polynomial encoding of digital signals, (b) appends those parity bits to the digital signal, and (c) uses decoding algorithms that detect errors in the received digital signal.
Note: Error correction, if required, may be accomplished through the use of an automatic repeat-request (ARQ) system. Also, an error checking mechanism that checks data integrity by computing a polynomial algorithm based checksum. [INFOSEC-99] (ATIS)

Crest Factor



Also referred to as peak-to-average ratio (PAR) or peak-to-average power ratio (PAPR); a measurement of a waveform, calculated from the peak amplitude of the waveform divided by the RMS value of the waveform.

 c = {|x|_\mathrm{peak} \over x_\mathrm{rms}}
It is therefore a dimensionless quantity. While this quotient is most simply expressed by a positive rational number, in commercial products it is also commonly stated as the ratio of two whole numbers, e.g., 2:1. In signal processing applications it is often expressed in decibels (dB). The minimum possible crest factor is 1, 1:1 or 0 dB. (Wikipedia)

This table provides crest factor values for some normalized waveforms:



Notes: 1. crest factors specified for QPSK, QAM, and WCDMA are typical factors needed for reliable communication, not the theoretical crest factors which can be larger.


Crimp Ring

A metallic ring which will be mechanically shaped to pro-vide retention of the coaxial cable braid and jacket onto "F" type connectors. They are usually incorporated into these connectors. (Arris Glossary of Terms)
Crimp Tool

A tool used to provide retention of an "F" type connector onto the braid and jacket of a drop cable. (Arris Glossary of Terms)

Critical Angle



In geometric optics, at a refractive boundary, the smallest angle of incidence at which total internal reflection occurs. (FiberOpticsInfo)

c:\users\cyoung\desktop\glossary of terms\drawings_diagrams\critical-angle.gif

Critical Angle Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/c


Critical Length
Distance along a specific cable to cause worst-case mismatch reflection. A function of frequency-attenuation-velocity of propagation parameters of specific cable types.

CRL
Certificate Revocation List

Cross Connect



The physical connection between patch panels or punch-down blocks that facilitates connections from systems and feeds to drops. (Linear LLC) Connections between terminal blocks on the two sides of a distribution frame or between terminals on a terminal block (also called straps). Also called cross-connection or jumper. (FiberOpticsInfo)

 
Cross Modulation


A form of television signal distortion where modulation from one or more television channels is imposed on another channel or channels. Also referred to as XMOD.

Cross-gain Modulation (XGM)



A technique used in wavelength converters where gain saturation effects in an active optical device, such as a semiconductor optical amplifier (SOA), allow the conversion of the optical wavelength. Better at shorter wavelengths (e.g. 780 nm or 850 nm). (FiberOpticsInfo)
Cross-phase Modulation (XPM)

A fiber nonlinearity caused by the nonlinear index of refraction of glass. The index of refraction varies with optical power level which causes different optical signals to interact. (FiberOpticsInfo)

Cross Ownership
Ownership of two or more kinds of communications outlets by the same individual or business. The FCC prohibits television stations and telephone companies from owning cable systems in their service areas. Television networks are prohibited from owning cable systems anywhere in the U.S.

Crosstalk
Noise passed between communications cables or device elements. 1) Undesired coupling from one circuit, part of a circuit, or channel to another. 2) Any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates and undesired effect in another circuit or channel.
(FiberOpticsInfo)

CRT


Cathode Ray Tube

Cryptanalysis


The process of recovering the plaintext of a message or the encryption key without access to the key.

Cryptographic Algorithm


An algorithm used to transfer text between plaintext and ciphertext.


CSA


Common Scrambling Algorithm

CSCF

Call State Control Function



CSD
Circuit Switched Data

CSMA/CD
Carrier Sense Multiple Access with Collision Detection; a network control protocol in which (a) a carrier sensing is used and (b) while a transmitting data station that detects another signal while transmitting a frame, stops transmitting that frame, waits for a jam signal, and then waits for a random time interval before trying to send that frame again.
(FiberOpticsInfo)

CSO
Composite Second Order Beat

CSR
Customer Service Representative

CSS
Cascading Style Sheets

CSU

Channel Service Unit; A digital interface device that connects end-user equipment to the local digital telephone loop. CSU is frequently coupled with DSU (see below) as CSU/DSU. (Satnews)


CSV


Circuit Switched Voice

CTB
Composite Triple Beat

CTIA

Cellular Telecommunications Industry Association



CTP
Compliance Test Plan

CTS



Clear To Send; in a communications network, a signal from a remote receiver to a transmitter that it is ready to receive a transmission. (FiberOpticsInfo)
Cumulative Leak Index (CLI)

A standard measurement of system leakage; when cable network equipment, coaxial cable, and connectors are imperfectly shielded signals leak out of the system (referred to as “egress”). Signal egress interferes with radio communications services and is of particular concern when it affects aeronautical navigation and communication services. The US Federal Communication Commission (FCC) therefore has stringent regulations regarding cable system egress in the 108 to 137 MHz and 225 to 400 MHz frequency bands. (Rhea, Cable Television Signal Distribution)

Current, Alternating (AC)

An electric current that periodically reverses the direction of electron flow. The rate at which a full cycle occurs in a given unit of time (generally a second) is called the frequency of the current. (Arris Glossary of Terms)
Current, Direct (DC)

Electrical current whose electrons flow in one direction only. It may be constant or pulsating as long as the movement is in the same direction. (Arris Glossary of Terms)
Custom Local Area Signaling Services (CLASS)
This term refers to a set of voice telephony services that make use of information about the calling or called numbers. Examples are caller ID, Automatic recall (*69), anonymous call rejection, etc.

Customer Premises Equipment (CPE)


Equipment at the end user's premises; MAY be provided by the end user or the service provider.


Customer Service Representative (CSR)
Customer service representative.

Cutback Method



A technique of measuring optical fiber attenuation by measuring the optical power at two points at different distances from the test source. (FiberOpticsInfo)

Cutoff Frequency
That frequency beyond which no appreciable energy is transmitted. It may refer to either an upper or lower limit of a frequency band.

Cutoff Frequency

A photo detector (PD) specification describing the frequency at which the PD photocurrent decreases by 3-dB from its highest level low frequency response. (Zanger)


Cutoff Wavelength



In single-mode fiber (SMF), the wavelength below which the fiber ceases to be single-mode. (FiberOpticsInfo)

CVC
Code Verification Certificate

CW
Control Word

CW

Continuous Wave; usually refers to the constant optical output from an optical source when it is biased (i.e., turned on) but not modulated with a signal. (FiberOpticsInfo)

CWDM
Coarse Wavelength Division Multiplexing

Cycle

One complete sequence of values of an alternating wave starting at zero, increasing to a maximum positive value, decreasing to zero, increasing to a maximum negative value, and decreasing to zero again. Also called a Hertz (Hz). (Arris Glossary of Terms)
Cyclic Redundancy Check (CRC)
An algorithm to detect data corruption.


D:

D1



A format for component digital video tape recording working to the ITU-R 601, 4:2:2 standard using 8-bit sampling. (FiberOpticsInfo)
D2

The VTR standard for digital composite (coded) NTSC or PAL signals that uses data conforming to SMPTE 244M. (FiberOpticsInfo)
D3

A composite digital video recording format that uses data conforming to SMPTE 244M. (FiberOpticsInfo)
D5

An uncompressed tape format for component digital video which has provisions for HDTV recording by use of 4:1 compression. (FiberOpticsInfo)

D Channel
An ISDN Data channel is a data connection between the telephone company's switching equipment and a customer's ISDN equipment. It carries telephone connection information—signals to tell your equipment that a call is coming in and carry dialing and call handling information to the phone company's equipment— and can also be used to carry multiple low-speed data connections using the X.25 packet-switching protocol.

DAC

Digital-to-Analog Converter; a device used to convert digital signals to analog signals. (FiberOpticsInfo)

c:\users\cyoung\desktop\glossary of terms\drawings_diagrams\d-a-converter.gif

Digital-to-Analog Converter (DAC) Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/d


DAMA

Demand-Assigned Multiple Access; A highly efficient means of instantaneously assigning telephony channels in a transponder according to immediate traffic demands. (Satnews)
DANL

Displayed Average Noise Level or “Noise Floor” is the specified noise level of a spectrum analyzer when terminated with a 50-Ohm load. (Yurick) DANL is dependent on various settings of the instrument, and is typically specified along with the conditions at which it was measured. For example, a typical DANL specification might read something like: -115 dBm between 1 GHz and 2.7 GHz with resolution bandwidth (RBW) set to 1 kHz with 0 dB input attenuation at 25deg C. Because the apparent noise floor of the instrument increases with a wider resolution bandwidth, the noise floor is often normalized to a common RBW, which is often 1 Hz. (NationalInstruments)
Dark Current

The current through the photodiode in the absence of light, when it is operated in photoconductive mode. The dark current includes photocurrent generated by background radiation and the saturation current of the semiconductor junction. Dark current must be accounted for by calibration if a photodiode is used to make an accurate optical power measurement, and it is also a source of noise when a photodiode is used in an optical communication system. (Zanger)
Dark Fiber
Fiber-optic cable that has been deployed but does not have the proper electronic and optical equipment to carry optical (light) signals. Generally considered to be extra fiber that will support future demand for communications capacity.

DASE
Digital Application Software Environment

Data Communication


The movement of encoded information by means of electrical transmission systems. The transmission of data from one point to another over communication channels.

Data Compression


A technique that saves storage space by eliminating gaps, empty fields, redundancies, or unnecessary data to shorten the length of records or blocks.

Data Dependent Jitter (DDJ)



Also called data dependent distortion. Jitter related to the transmitted symbol sequence. DDJ is caused by the limited bandwidth characteristics, non-ideal individual pulse responses, and imperfections in the optical channel components. (FiberOpticsInfo)
Data Link

A fiber optic transmitter, cable and receiver that transmits digital data between two points. (Arris Glossary of Terms)
Data Link Layer
Layer 2 in the Open System Interconnection (OSI) architecture; the layer that provides services to transfer data over the transmission link between open systems.

Data Rate



The number of bits of information in a transmission system, expressed in bits per second (b/s or bps), and which may or may not be equal to the signal or baud rate. (FiberOpticsInfo)

Data Over Cable Service Interface Specifications (DOCSIS®)
Specification for transmission of data over a cable network that has been approved by the ITU as an international standard. DOCSIS® was developed by CableLabs and a consortium of North American multi-system cable operators.

DAVIC
Digital Audio Visual Council

dB
Decibel

DBA

Dynamic Bandwidth Allocation



dBc

A measure of spurious signal level. The level is measured relative to the nominal unmodulated carrier level. (Arris Glossary of Terms)
dBi

Decibel-isotropic; a unit of measure that expresses a ratio of power, measured in decibels, referring to the gain or loss relative to a dipole antenna. (Arris Glossary of Terms)
dBµV

dB micro volts. A measurement of ‘x dBµV’ indicates that the signal is x dB above one microvolt in 75 ohms. To convert x microvolts to dBµV: dBµV = 20 log (x microvolts). (Blonder Tongue Laboratories)
dBm

Decibel referred to one milliwatt; 0 dBm = 1 mW. (Arris Glossary of Terms)
dBmV

dB milli volts. A measure of signal amplitude. 0 dBmV is equivalent to 1 mV RMS across the given impedance (usually 75 Ohms). (Arris Glossary of Terms). dBmV and dBµV are expressions of power that contain an upper case “V”. This does not mean they are expressions of voltage. They are expressions of power. When all the power scales (dBm, dBmV and dBµV) are laid next to each other, it is easy to see that each track on a dB for dB basis. A power measurement of ‘x dBmV’ indicates that a particular signal is x dB greater than (‘above’) 1 millivolt in 75 ohms. A negative dBmV value indicates that the signal is x dB less than (‘below’) 1 millivolt in 75 ohms. To convert x millivolts to dBmV: dBmV = 20 log (x millivolts) (Blonder Tongue Laboratories)
dBRL

Return loss as measured with a TDR and expressed in dB. It is the ratio of power levels between an outgoing pulse and its reflection. This unit of measure can assist in determining the severity of a cable fault. (Arris Glossary of Terms)
DBS
Direct Broadcast Satellite; also referred to as SATCOM-DBS. An alternative to cable and analog satellite reception that uses a fixed 18-inch dish focused on one or more geostationary satellites. DBS units receive multiple channels of multiplexed video and audio signals as well as programming information and related data. Also known as digital satellite system.
(FiberOpticsInfo)
dBW

The ratio of the power to one Watt expressed in decibels. (Satnews)
DC

Direct current. See also current, direct.
DCD

Duty Cycle Distortion Jitter (FiberOpticsInfo)
DC Power Block

A device which stops the flow of dc power but permits passage of higher frequency ac signals. (Channel Vision)


DCAA


Digital Certificate Authorization Agreement

DCE

Data Circuit-terminating Equipment. 1) In a data station, the equipment that performs functions such as signal conversion and coding, at the network end of the line between the data terminal equipment (DTE) and the line, and may be a separate or an integral part of the DTE or of intermediate equipment. 2) The interfacing equipment that may be required to couple the data terminal equipment (DTE) into a transmission circuit or channel and from a transmission circuit of a channel into the DTE. (FiberOpticsInfo)

DCR


Digital Cable Ready

DCT

Discrete Cosine Transform (FiberOpticsInfo)
DDE-1
Declarative Data Essence

DDJ

Data Dependent Jitter (FiberOpticsInfo)
Dead Zone

Period of time after a reflected pulse is detected before another feature may be measured. (Arris Glossary of Terms)
De-BPSK

Differential Binary Phase Shift Keying (Satnews)
Decibel (dB)
A unit to measure the relative levels of current, voltage or power. An increase of 3 dB indicates a doubling of power, an increase of 10 dB indicates a 10x increase in power, and an increase of 20 dB indicates a 100x increase in power.



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