An assembly of one or more conductors insulated from each other and from the outside by a protective sheath.[Arr11]
Signals from an inserted modulated channel that travel back into the cable source. Using a modulator on a cable service provider's system (CATV or MATV) requires a mixing amplifier or filter (NF-469) to prevent the signal from back-feeding in the cable or antenna system. [Lin07]
The amount of RF signal attenuation by a given coaxial cable. Cable attenuation is mainly a function of signal frequency and cable length. Defines the amount of cable loss that an amplifier is aligned (pre-equalized) to compensate for during factory alignment with the aim of producing flat frequency response in a fielded condition. Aligning an amplifier through cable creates a tilted gain response. Cables attenuate higher frequency signals more than lower frequency signals, according to a logarithmic function. Cable losses are usually calculated and specified for the highest frequency carried (greatest loss) on the cable.[Arr11]
Cable Modem (CM)
A modulator-demodulator at subscriber locations intended for use in conveying data communications on a cable television system. Cable Modems offer a very high speed connection to the Internet, up to 30Megabits per second (several hundred times the speed of a 56Kbps modem). Technically speaking, though, a cable modem is not a modem at all, but a broadband network bridge.
Cable Modem Termination System (CMTS)
Located at the cable television system headend or distribution hub, a CMTS provides complementary functionality to the cable modems to enable data connectivity to a wide-area network. Link to CMTS tutorial: http://www.youtube.com/watch?v=0qmaXdudMxg&NR=1
Cable Modem Termination System-Network Side Interface (CMTS-NSI)
The interface between a CMTS and the equipment on its network side.
Cable Modem to CPE Interface (CMCI)
The part of the DOCSIS specification defining the communication between the cable modem and consumer premise equipment (CPE) devices.
Refers to the cable television plant that would typically be used for data over cable services. Such plants generally employ a downstream path in the range of 54 MHz on the low end to a high end in the 440 to 750 MHz range and an upstream path in the range of 5 to 42 MHz. Customers share a common communication path for upstream and a separate common path for downstream (i.e., effectively a pair of unidirectional buses).
Devices obtaining a/c. power simultaneously with RF on the coaxial cable.
A method of supplying power to solid-state cable television equipment by using the coaxial cable to carry both signal and power simultaneously.
A television receiver that can receive unscrambled cable television channels without the use of a converter. [Cha07]
Facility that provides cable service in a given geographic area comprised of one or more headends.
Cable Television Relay Services (CARS)
Terrestrial microwave frequency band used to relay television, FM radio, cablecasting and other signals from the original reception site to the headend terminal for distribution over cable.
RF frequency signals traveling in coaxial cable will reflect off any impedance that does not match the 75-ohm impedance of the cable. This will cause serious signal distortion. For this reason, the ends of all the trunk and distribution cables are terminated with a 75-ohm load to ground.
Used in a cable system where it becomes necessary to terminate both RF signal and 60 Hz AC power.[Arr11]
The increase in cable attenuation as the frequency increases.[Arr11]
A communications system which distributes broadcast programs and original programs and services by means of coaxial cable.
A removable security module (in a PCMCIA or PC card form factor) which, when inserted in an OpenCable certified set-top, television or other device, enables delivery of digital video programming and other services. The OpenCable specification is designed in part to support the retail sale of advanced digital set- top boxes and other devices. CableCARDs will be provided directly by the cable operator to customers who request them. Or a CableCARD is a detachable device, distributed by cable providers, that connects to the home receiver. The interface between the CableCARD unit and the receiver is specified by the OpenCable platform. CableCARD functionality includes copy protection and signal demodulation.
To originate programming over a cable system. Includes public access programming.
Cable industry sponsored organization for the development, creation, and maintenance of standards, specifications, best practices, and test methodology. CableLabs also provides cable industry equipment interoperability and certification test. CableLabs is headquarted in Colorado USA. Link to CableLabs web site: www.cablelabs.com.
A software product developed by TapSCAN which tabulated Nielsen household and demographic data for cable.
Communications Assistance for Law Enforcement Act
In a PacketCable™ 1.0-based network, Call Agent is a synonym for Call Management Server (CMS). The term originates from the Simple Gateway Control Protocol (SGCP) specification. The Call Agent or CMS maintains network intelligence and call state, and controls the media gateway. “Server” is sometimes also used as a synonym for Call Agent or Call Management Server.
A Call Appearance is an iteration of a telephone Directory Number (DN) that allows multiple concurrent calls to the same phone number. An ISDN line with three call appearances for a single DN, for example, can have three people on the line or on hold to the same number at the same time.
Call Detail Record (CDR)
A data record typically used in a telephony system to record usage information on a per-call basis. Typical fields in the record include originating number, terminating number, start-time, duration, etc.
Call Management Server (CMS)
In a PacketCable™ 1.0-based system, this is the entity that maintains call state and implements features, such as Custom Local Area Signaling Service (CLASS) features. The CMS controls both the in-home media gateways and the media gateways connecting to the Public Switched Telephone Network (PSTN). The CMS also performs admission control and routing functions.
Caller ID is a telephone company feature that notifies a telephone being called of who is (or at least what phone number is) originating the call. On analog POTS phone systems, Caller ID information is transmitted to the telephone set between the first and second ring of the phone. On ISDN sets, Caller ID data is sent as part of the Q9.31 “call setup” information sent of the ISDN D channel. Some states, like California, regulate the implementation of Caller ID very strictly, requiring that phone companies offer their customers the option of keeping their numbers private when placing a call.
A type of mounting bracket, located at the end of an off-air antenna, designed to fasten the antenna to a structure.[Arr11]
CableHome Address Portal
ISDN Capability Packages, like Capability Package U, are standardized ISDN feature sets defined by ISDN Order Codes.
The ability of a dielectric material between conductors to store electricity, when a difference of potential exists between the conductors. The unit of measurement is the farad, which is the capacitance value which will store a charge of one coulomb when a one-volt potential difference exists between the conductors. In AC, one farad is the capacitance value which will permit one ampere of current, when the voltage across the capacitor changes at the rate of one volt per second.[Arr11]
Two conducting surfaces separated by a dielectric material. The capacitance is determined by the area of the surfaces, type of dielectric, and spacing between the conducting surfaces.[Arr11]
A cable system's procedure of carrying the signals of television stations on its various channels. FCC rules determine which signals cable systems must or may carry.
An alternating-current wave of constant frequency, phase and amplitude. By varying (modulating) the frequency, phase or amplitude of a carrier wave, information is transmitted.
Carrier Hum Modulation
The peak-to-peak magnitude of the amplitude distortion relative to the Radio Frequency (RF) carrier signal level due to the fundamental and low-order harmonics of the power-supply frequency.
Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
The Ethernet media access method. All network devices contend equally for access to transmit. If a device detects another device's signal while it is transmitting, it aborts transmission and retries after a brief pause.
Carrier-to-Noise Ratio (C/N or CNR)
The square of the ratio of the root mean square (RMS) of the voltage of the digitally-modulated Radio Frequency (RF) carrier to the RMS of the continuous random noise voltage in the defined measurement bandwidth. (If not specified explicitly, the measurement bandwidth is the symbol rate of the digital modulation; for video it is 4 MHz.)
CNR Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/c
Cable Television Relay Services
Container for recorded programming designed to be shown on a television receiver. The cartridge contains a reel of motion picture film, videotape or electronically embossed vinyl tape, blank or recorded, and uses an external take- up reel.
Conditional Access System
The operation of two or more amplifiers in series so that the output of one device feeds the input of the next.[Arr11]
The number of amplifiers between the headend and the specific subscriber.
Cascaded 1 dB Compression Point (P1dB)
Total P1dB (dB) = 10*log10 ((1/ (p1dB1*gain2*gain3) + 1/ (p1dB2*gain3) + 1/ (p1dB3)) ^-1)
Top of Form
Note: The calculations for Total P1dB and NF use linear values (NOT dB) for NF, P1dB, and gain. Need more stages and more system parameters? Try the free Cascade101 Worksheet[Mic11]
Cascading Style Sheets (CSS)
An extension to HTML to allow styles, e.g. color, font, size to be specified for certain elements of a hypertext document. Style information can be included in-line in the HTML file or in a separate CSS file (which can then be easily shared by multiple HTML files).
An amplifier consisting of a grounded-emitter input stage that drives a grounded-base output stage; advantages include high gain and low noise; widely used in television tuners. [Ans11]
Cascode Amplifier Diagram courtesy of http://www.wiringdiagrams21.com/wp-content/uploads/2009/11/Cascode-Video-FET-Amplifier-Circuit-Diagram.png
A type of satellite antenna receive feed that employs a reflector to direct the satellite signal via a waveguide to an low noise amplifier (LNA) or low noise block converter (LNB).[Arr11]
Cassegrain Feed System
An antenna feed design that includes a primary reflector, the dish, and a secondary reflector which redirects microwaves via a waveguide to a low noise amplifier (LNA) or low noise block converter (LNB).[Arr11]
A self-contained package of reel-to-reel blank or recorded film, videotape or electronically embossed vinyl tape which is continuous and self-rewinding. Similar to a cartridge, but of slightly different design.
Conditional Access Table
CableHome Address Translation
Twisted pair communications circuits are rated by category, whose specifications are covered under EIA/TIA 568. The higher the category number, the higher the information capacity of the circuit. [Lin07]
A cathode is the opposite of an anode. A cathode in a television is essentially a filament coated in a substance that gives off negative electrons when heated. In many ways, the filament is like the filament on a light bulb. [Glo07]
Community Antenna Television System
CATV Hybrid Amplifier Module
Also referred to as a CATV Hybrid, Hybrid Amplifier, or “hybrid”. In cable plant, including HFC networks, a term used to describe an amplifier module made up of transistor amplifier elements combined with passive elements to form a CATV hybrid amplifier module. Usually manufactured using the cable industry specific SOT-115J package developed in original form in 1968 by TRW. The first hybrid amplifiers used within revenue generating cable television networks were Lindsay Broadband enabled trunk, bridger, and line extender amplifiers installed in Belgium in 1973.
Drawing courtesy of “Reliability Considerations in CATV Hybrids”, IEEE Transactions On Cable Television, VOL. CATV-3, NO. 1, January 1978, Al Grant and Jim Eachus, Motorola, Inc.
A numerical value that indicates the current status of an ISDN call session and what caused that change in status.