 |
| Send e-mail |
|
| Contacts |
Teleste Corporation
P.O.Box 323
FI-20101 Turku
Finland
Tel. +358 (0)2 260 5611
Verkkolaskutus
OVT-tunnus
003711022678
Operaattori
TietoEnator
Tilinumero TE003711022678
More information
|
|
|
|
Access Channels
|
Dedicated channels giving nondiscriminatory access to the cable
system by the public, government agencies, or school systems.
|
|
Access Network
|
The part of the carrier network that touches the customer's
premises. The Access network is also referred to as the local drop,
local loop, or last mile.
|
|
Access Node (AN)
|
Part of the Access Network which performs some or all of the
following:
- Modulating forward data onto the Access Network
-
Demodulating return-path data
- Enforcing the MAC protocol for
access onto the Access Network
Separating or classifying
traffic prior to multiplexing onto the Transport Network; such as
- Differentiating traffic that is subject to QoS guarantees from
traffic that receives best-effort support.
- Enforcing signaling
- Handling passive operations, such as splitting and filtering.
|
|
Active
|
Power circuitry containing transistors, such as amplifiers, power
supplies or converters.
|
|
Addressable
|
Able to signal from the headend or hub in such a way that only the
desired subscriber's receiving equipment is affected. In this way,
it is possible to send a signal to a single subscriber and effect
changes in the subscriber's level of service.
|
|
Ariel plant
|
Cable that is suspended in the air on telephone or electric utility
poles.
|
|
AGC Threshold
|
The level of imput current at which the AGC circuit becomes active.
|
|
AGC Time Constant
|
The amount of time it takes to achieve the required AGC level; also
the amount of time it takes to recover from AGC.
|
|
Alternative access provider
|
A telecommunications provider, other than the local telephone
company, that provides a connection between a customer's premises to
a point of presence of the long distance carrier.
|
|
Amplifier
|
A device the boosts the strength of an electronic signal. In a cable
system, amplifiers are spaced at regular intervals throughout the
system to keep signals picture-perfect regardless of how far your
live from the headend.
|
|
Amplitude Modulation
|
The process of impressing information on a radio-frequency signal by
varying its amplitude. Generally amplitude modulation is due for the
purpose of relaying messages by voices, television, facsimile or
other modes.
|
|
Analog (data transmission)
|
Signals in the form of continuously variable physical quantities.
|
|
|
|
Analog Device
|
A device that operates with variables represented by continuously
measured quantities such as voltages, resistances, rotations and
pressures.
|
|
Analog Signal
|
A signal that is solely dependent of magnitude to express the
information content.
|
|
Analog-To-Digital
|
A device that converts a signal whose input is information in the
analog form and whose output is the same information in digital form.
|
|
Antenna
|
A structure or devise used to receiving or transmitting
electromagnetic waves.
|
|
Antenna Array
|
A group of identical antennas arranged and interconnected for
achieving greater directivity (gain) or beam shaping.
|
|
Antenna Stack
|
Antenna tower with multiple antennas and supports.
|
|
Asynchronous transfer mode (ATM)
|
The transfer mode in which the information is organized into cells.
It is asynchronous in the sense that the recurrence of cells
containing information from an individual user is not necessarily
periodic.
|
|
ATM cell
|
A digital information block of fixed length (53 octets) identified
by a label at the ATM layer.
|
|
Attenuation
|
The decrease in amplitude of a signal between any two points in a
circuit. Usually expressed in decibels. Attenuation is the opposite
of amplification.
|
|
Audio
|
Relating to sound or its reproduction; used in the transmission or
reception of sound.
|
|
Automatic Gain Control (AGC)
|
Used to protect a device from optical overload while maintaining
bandwidth and sensitivity performance.
|
|
Automatic Slope Control (ASC)
|
Circuitry which permits amplifier response compensation for varying
slope (tilt) at its input.
|
|
Available bit rate (ABR)
|
An ATM layer service where the limiting ATM-layer transfer
characteristics provided by the network may change subsequent to
connection established.
|
|
Backbone Microwave System
|
A series of directional microwave paths carrying common information
to be relayed between remote points; engineered to allow insertion
of signals, dropping off of signals and switching of signals along
its length at designated relay points.
|
|
Background Noise
|
In an amplifier or other device that draws current, there is always
some noise output in addition to the desired signal.
|
|
Bandwidth
|
A measure of the information-carrying capacity of a communication
channel. The bandwidth corresponds to the difference between the
lowest and highest frequency signal which can be carried by the
channel.
|
|
Baud Rate
|
The measure of the speed of transmission of a digital code.
|
|
Basic Cable
|
The basic program services distributed by a cable system for a basic
monthly fee. These include one or more local broadcast stations,
distant broadcast stations, non-pay networks and local origination
programming.
|
|
Bit
|
A binary digit. The binary systems of numbers is often called base
2. All binary digits consist of combinations of 0's and 1's.
|
|
Bit Error Rate (BER)
|
The fraction of bits transmitted that are received incorrectly.
|
|
Bit Rate
|
The rate of a binary-coded transmission which is the number of bits
per second.
|
|
Bridger Amplifier
|
Trunk amplifiers serve not only to boost the signal and pass it
along, but also to provide branching lines, called feeders, for
distribution of the signals to subscribers. The bridger amplifier is
housed in the same case as the trunk amplifier. It taps the trunk at
about +20 dBmV and splits the signal into 2 to 4 feeder lines.
|
|
Bridged Tap
|
Wires that are connected to a network, in which one end of the wire
is unconnected to proper termination equipment. (Ex: A consumer or
technician removes devices without completely disconnecting to the
old device.)
|
|
Broadband
|
Any system able to deliver multiple channels and/or services to its
users or subscribers. Broadcast television, cable television,
microwave and satellite are examples of broadband technologies.
|
|
Broadband Modulation
|
The transfer of information by a radio signal requires a certain
minimum amount of spectrum space. This minimum depends on the rate
at which this information is conveyed. Sometimes called wideband
modulation.
|
|
Broadcasting
|
The dissemination of any form of radio electric communications by
means of Hertzian waves intended to be received by the public.
Transmission of over-the-air signals for public use.
|
|
Broadcast addresses
|
A predefined destination address that denotes the set of all service
access points.
|
|
Brouter
|
A device that routes specific protocols, such as TCP/IP and IPX, and
bridges other protocols, thereby combining the functions of both
routers and bridges.
|
|
Burst error second
|
Any errored second containing at least 100 errors.
|
|
Bus
|
A LAN topology in which all the nodes are connected to a single
cable. All nodes are considered equal and receive all transmissions
on the medium.
|
|
Byte
|
A data unit of eight bits.
|
|
Cable Loss
|
Defines the amount of cable loss that an amplifier is aligned
(pre-equalized) through during factory alignment. Aligning an
amplifier through cable creates a tilted gain response.
|
|
Cable System
|
Facility that provides cable service in a given geographical area,
comprised of one or more headends.
|
|
Cable-Powered
|
Devices obtaining a.c. power simultaneously with RF on the coaxial
cable.
|
|
CableSCAN
|
A software product developed by TapSCAN which tabulates Nielson
household and demographic data for cable.
|
|
Cable Termination
|
RF frequency signals travelling 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.
|
|
CATV
|
Community Antenna TeleVision also called Cable TV.
|
|
Carrier
|
An alternating-current wave of constant frequency, phae and
amplitude. By varying the frequency, phase or amplitude of a carrier
wave, information is transmitted.
|
|
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.
|
|
Cascade Depth
|
The number of amplifiers between the headend and the specific
subscriber.
|
|
Cell
|
ATM layer protocol data unit.
|
|
Central office (CO)
|
The central location in a traditional public network
telecommunication environment where access is available to signals
traveling in both the forward and reverse paths.
|
|
Channel
|
A signal path of specified bandwidth for conveying information.
|
|
Channel Capacity
|
The number of channels available for current or future use on a
cable system.
|
|
Coaxial cable
|
Actual line of transmission for carrying television signals . Its
principal conductor is either copper or copper-coated wire
surrounded by insulation and then incased in aluminum.
|
|
Cluster
|
The group of homes passed by a single fiber node.
|
|
Coaxial Cable
|
Cable with a central copper strand for transmitting electrical
signals, surrounded by a concentric air or insulation
(nonconducting) core, and enclosed by an outer (electrically
shielding) concentric metal fiber, either braided or solid.
|
|
Co-Channel
|
A form of interference caused by another signal occupying the same
channel frequency. Example - two signals are received in a headend,
from different locations, causing interference with each other as
received.
|
|
Code Division Multiple Access (CDMA)
|
A digital technology developed by QUALCOMM. With CDMA, unique
digital codes, rather than separate RF frequencies or channels, are
used to differentiate subscribers.
|
|
Collision
|
The result of two network nodes transmitting on the same channel at
the same time. The transmitted data is not usable.
|
|
Combiner
|
A signal combining network which allows several discrete inputs to
be added into a common bandwidth and having high isolation between
inputs. Also nay refer to a power combining network.
|
|
Common Path Distortion (CPD)
|
The interference of return path signaling caused by the forward path.
|
|
Communications Satellite
|
An electronic retransmission vehicle located in space in a fixed
earth orbit. Signals are transmitted to the satellite from earth
station antenna, amplified and sent back to earth for reception by
other earth station antennas.
|
|
Communication Server
|
A dedicated, standalone system that manages communications
activities for other computers.
|
|
Composite Triple Beat (CTB)
|
In multichannel systems using push-pull, PHD, and feed-forward
amplifiers, the limiting performance factor is usually composite
third order beats. The total number of beats that "pile up" at a
single frequency can be calculated. The composite triple figures are
with CW carriers at the output level and tilt listed on the
specification sheets. Any deviation creates on a 2:1 basis.
Worst-case CTB occurs at the high end of the amplifier's passband.
With TV modulated carriers, the average signal power is reduced.
measured composite triple beat levels are at least 6dB lower than
with CW carriers, and possibly as much as 10 dB lower when frequency
offsets are considered. the composite triple beat is measured with a
spectrum analyzer of 30 kHz resolution.
|
|
Compression
|
A method for compacting the digital representation of a signal for
more efficient transmission or storage.
|
|
Constant bit rate (CBR)
|
A service class intended for real-time applications, or those
requiring tightly constrained delay and delay variation, as would be
appropriate for voice and video applications. The consistent
availability of a fixed quantity of bandwidth is considered
appropriate for CBR service.
|
|
Contour
|
Grade A:
The geographical boundary of an area receiving a
given TV signal that is satisfactory 70% of the viewers 90% of the
time.
Grade B:
Borders of an area where the TV signal is
satisfactory to at least 50% of the viewer locations 90% of the time.
|
|
Converter
|
A device (in CATV) for permitting a standard TV set with a 12
channel VHF tuner to receive over 12 cable channels. Older types use
a multichannel TV tuner.
|
|
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.
|
|
Cross Modulation
|
"Cross-mod" - A form of synchronous triple beat between any two
channels where the modulation sideband (+/-)constitutes the third
beating frequency. More than one channel source may be additive and
appear to be baseband (modulation) interference on the affected
channel.
|
|
Crosstalk
|
Noise passed between communications cables or device elements.
|
|
DAVIC
|
Digital Audio Visual Counsil
|
|
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.
|
|
Decibel (dB)
|
A unit of measuring relative levels of current, voltage or power.
|
|
Delay
|
The elapsed time between the instant when user information is
submitted to the network and when it is received by the user at the
other end.
|
|
Demographics
|
Breakdown of television viewers by such factors as age, sex, income
levels, education and race.
|
|
Demodulation
|
The extraction of the modulation or information from a
radio-frequency current.
|
|
Dense Wave Division Multiplexing (DWDM)
|
A technology that provides in fiber the equivalent of frequency
division multiplexing, in metallic wire. Separate parallel channels
are transmitted on a single fiber, with one wavelength for each
channel. Current products enable 16 channels of 2.5 Gb each for a
total of 40 Gb per fiber. DWDM can operate over existing single-mode
fiber, and therefore reduce upgrade costs.
|
|
Descrambler
|
An electronic circuit that restores a scrambled video signal to its
standard form.
|
|
Detector
|
The photodiode in optical receivers.
|
|
Digital
|
The use of a binary computer code to represent information. In
cable, digital transmission is much clearer than analog. Digital
technology also allows for more information to be processed.
|
|
Digital Set Top Box
|
A device which accepts digital encoded television broadcasts and
converts them to display on an analog television set.
|
|
Direct Broadcast Satellite (DBS)
|
A high-powered ku-band satellite capable of offering TV signals from
a satellite to the home, for multichannel reception, with a small
(1-2 ft) antenna.
|
|
Digital compression
|
An engineering technique for converting an analog television signal
into a digital format.
|
|
Dish Antenna
|
A high-grain antenna, shaped like a dish, that is used for the
transmission and reception of ultra-high-frequency and microwave
signals.
|
|
Distant Signal
|
A broadcast signal originating outside the cable system's local
market.
|
|
Distribution system
|
Part of a cable system consisting of trunk and feeder cables.
|
|
DOCSIS
|
Data Over Cable Service Interface SpecificationsSpecification for
transmission of data over a cable network that has been approved by
the ITU as an international standard. DOCSIS was developed by MCNS,
a consortium consisting of CableLabs and a consortium of North
American multi-system operators.
|
|
Down Conversation
|
The heterdyning of an input signal with the output of local
oscillator, resulting in an intermediate frequency that is lower
than the incoming signal frequency.
|
|
Downlink
|
Transmission of signals from a satellite to a dish or earth station.
|
|
Downstream
|
or Forward Traffic - Signals transmitted to a subscriber.
|
|
Drop
|
The cable and hardware from tap to subscriber is called the drop.
|
|
Drop Cable
|
Generally 330 feet or less, of coaxial cable, starting at a tap and
continuing on to the subscriber's connection.
|
|
Dual cable
|
Two independent distribution systems operating side by side,
providing double the channel capacity of a single cable.
|
|
Duplex
|
In a communications channel, the ability to transmit in both
directions.
|
|
Earth Station
|
The antennas and other equipment needed on the ground to transmit or
receive satellite communication signals.
|
|
Education Access Channel
|
A cable television channel specifically designated for use by local
education authorities.
|
|
End user
|
A person, organization, or telecommunications system that accesses
the network in order to communicate via the services provided by the
network.
|
|
Errored second
|
Any one-second interval containing at least one bit error.
|
|
Ethernet
|
The most popular LAN technology in use today. The IEEE standard
802.3 defines the rules for configuring an Ethernet network. It is a
10 Mbps, CSMA/CD baseband network that runs over thin coax, thick
coax, twisted pair or fiber optic cable.
|
|
Extended subplot
|
A frequency division scheme that allows bi-directional traffic on a
single cable. Reverse path signals come to the headend from a 5 - 45
MHz. Forward path signals go to the headend from 54 to the upper
frequency limit.
|
|
F-Connector
|
The final piece of hardware (familiar to subscribers) on a drop
cable. It is cylindrical with a center pin sticking out, that plugs
into the set-top box, cable ready TV or VCR.
|
|
Factory Alignment
|
Refers to the bench test alignment conditions with the slope and
gain controls (where applicable) turned to maximum and no pad or
equalizer installed. These specs can be used to verify operation
during a bench test.
|
|
Federal Communications Commission (FCC)
|
The agency that regulates which communications services, including
cable television, at the federal level.
|
|
Fiber Distributed Digital Interface (FDDI)
|
A network based on the use of optical fiber to transmit data at a
rate of 100 Mb/s.
|
|
Feeder Cables
|
The cables that take signals from the trunk line to the subscriber
area and to which the subscriber taps are attached.
|
|
Feeder line
|
Cable distribution lines that connect the main trunk line or cable
to the smaller drop.
|
|
Fiber optics
|
Very thin and pliable tubes of glass or plastic used to carry wide
bands of frequencies.
|
|
Field Effect Transistor (FET)
|
A low amplifying device available in many different forms including
a gallium arsenide. Ideal for use in high-gain, low-noise amplifier
circuits, especially at ultrahigh and microwave frequencies.
|
|
Fiber Optics
|
A method of transmitting signals over light waves sent through
extremely thin fibers spun from glass.
|
|
Filter
|
A passive or active frequency selective circuit designed to modify a
signal or source of power.
|
|
FM Broadcast Band
|
The band of frequencies extending from 88 to 109 MHz.
|
|
FM Cable system
|
FM radio signals offered by the cable system (the cable must be
connected to the subscriber's FM stereo receiver.)
|
|
Forward Error Correction (FEC)
|
FEC enables the receiver to detect and fix errors to packets without
the need for the transmitter to retransmit packets.
|
|
Forward Traffic
|
also Downstream or forward channel - Signals transmitted to a
subscriber from the headend.
|
|
Fragmentation
|
When broad television audiences break into smaller segments due to
multiple viewing choices and niche programming that targets
particular demographics.
|
|
Franchise
|
A contract between a cable television company and a municipal
government authorizing the company to install cable and offer cable
television service within the community.
|
|
Frequency
|
The number of times a complete electromagnetic wave cycle occurs in
a fixed unit of time, usually one second. The rate at which a
current alternates, measured in Hertz on a telecommunications medium.
|
|
Frequency Modulation (FM)
|
A common method of transmitting information over a carrier wave by
changing its frequency.
|
|
Front End
|
The first radio-frequency amplifier stage in a receiver. This is one
of the most critical components of the receiver because because the
sensitivity of the front end dictates the sensitivity of the entire
receiver.
|
|
Full-Duplex
|
Independent, simultaneous two-way transmission in both directions,
as opposed to half-duplex transmission.
|
|
Full-Motion Video
|
Not compressed; a standard video signal of 30 frames per second, 525
horizontal lines per frame, capable of complete action.
|
|
Full Service Network (FSN)
|
Cable networks that are intended to provide everything; that is
broadcast TV, internet access, VOD, and voice telephony.
|
|
Gain Control
|
An adjustable control that changes the gain of an amplifier.
|
|
Gain Slope
|
A linear variation in gain from the lowest frequency to the highest
frequency.
|
|
Gateway
|
A computing machine which is both connected to one or more networks
and is capable of passing network information from one network to
another.
|
|
GigaHertz (GHz)
|
One billion cycles of electrical frequency per second.
|
|
Ground Communication Equipment
|
Satellite earth station electronic equipment.
|
|
Half-Duplex
|
Two-way transmission, one way at a time.
|
|
Head-End
|
The control center of a cable television system, where incoming
signals are amplified, converted, processed and combined into a
common cable along with any original cablecasting, for transmission
to subscribers. The system usually includes antennas, preamplifiers,
frequency converters, demodulators, modulators, processors and other
related equipment.
|
|
Head-End Router
|
The computer, at the cable headend, responsible for gateway
operations between the headend and the internet.
|
|
Header
|
Protocol control information located at the beginning of a protocol
data unit.
|
|
Hertz (Hz)
|
A unit of frequency equivalent to one cycle per second.
|
|
Heterodyne
|
A process of the shifting of a signal of interest down to a
frequency at which it may be processed more easily to extract
information.
|
|
High Definition Television (HDTV)
|
A very high quality television signal with picture resolution nearly
equal to that of film.
|
|
High Electron Mobility (HEMT)
|
A transistor that yields the lowest noise figures in single FET
devices.
|
|
High Q
|
A fiber circuit with a great deal of selectivity.
|
|
High Split
|
When the upstream frequencies are 5-150/174-750 MHz; this split
provides the greatest amount of return path.
|
|
Homes Passed
|
The number of homes in which a cable television service is or can be
made available by adding a drop to an already existing feeder line.
|
|
Hub
|
A signal distribution point for part of an overall system. Larger
cable systems are often served by multiple hub sites, with each hub
in turn linked to the main headend with a transportation link such
as fiber optics, coaxial supertrunk, or microwave.
|
|
Hybrid Fiber Coax (HFC)
|
A network consisting of fiber optical cables and coaxial cables.
|
|
IEEE
|
Institute of Electrical and Electronics Engineers
|
|
Impedance
|
Resistance to alternating-current flow.
|
|
Independent Operator
|
Individually owned and operated cable television system, not
affiliated with an MSP.
|
|
Inductance
|
The ability of a device to store energy in the form of a magnetic
field.
|
|
Inductor
|
An electronic component designed to provide a controlled amount of
inductance.
|
|
Infomercial
|
A commercial, usually 90 seconds or more in length, designed to
supply information about a product or service rather than to present
a specific sales message.
|
|
Interactive Cable
|
Cable systems that have the technical ability to let subscribers
communicate directly with a computer at the system headend from
their television sets, using special converters and the regular
cable lines. Viewers are able to order movies and video games,
access library information and request sales brochures and coupons
from home.
|
|
Interconnect
|
Two or more cable systems distributing a programming or commercial
signal simultaneously.
|
|
Interdiction
|
A method of receiving TV signals by jamming unauthorized signals but
having all other signals received in the clear. Because the jamming
is accomplished outside the home and does not require a set-top
terminal in the home.
|
|
Interlacing
|
The television display format, where horizontal lines of pixels are
illuminated in an alternating pattern rather than sequentially.
|
|
Intermodulation
|
In a receiver, an unwanted signal sometimes interacts with the
desired signal. The desired signal appears to be modulated by the
undesired signal.
|
|
Internet, The
|
A series of interconnected local, regional, national and
international networks, linked using TCP/IP. The Internet is
accessible via telephony wires, HFC networks and by satellite.
|
|
International Television Fixed Services (ITFS)
|
The ITFS television transmission system was first authorized by the
FFF for educational television in the 2.5 to 2.686 GHz band. The
ITFS band has been re-allocated for shared operation among
multipoint distribution services, multichannel multipoint
distribution services, operational fixed services, and ITFS users.
|
|
Internet Protocol (IP)
|
The computer network protocol (analogous to written and verbal
languages) that all machines on the internet must know so that they
can communicate with one another.
|
|
Ku-band
|
The group of microwave frequencies from 12 to 18 GHz; the band of
satellite downlink frequencies from 11.7 to 12.2 GHz.
|
|
Laser
|
A device that generates coherent electromagnetic radiation in, or
near, the visible part of the spectrum.
|
|
Last Mile Framing
|
The data encapsulation and transmission protocols used between the
consumer premises and the head end. Framing techniques include ATM,
MPEG and IP.
|
|
Layer
|
In networks, layers refer to software protocol levels comprising the
architecture, with each layer performing functions for the layers
above it.
|
|
Leased Access
|
or Leased Channel - On some systems, a public access channel for
which programmers pay a fee for use and are permitted to sell
commercial time in their programming.
|
|
Line Speed
|
Expressed in bps, the maximum rate at which data can reliably be
transmitted over a line using given hardware.
|
|
Local Area Network (LAN)
|
Private transmission network interconnecting offices within a
building or group of buildings, and usually designed to convey
traffic (voice, video, data, and facsimile.) A LAN usually includes
a computer network made up of computer, printers and mass storage
units.
|
|
Local Exchange
|
An exchange where telephone subscriber lines connect.
|
|
Local Exchange Carrier (LED)
|
A local telephone company within a serving area or LATA.
|
|
Local Loop
|
The set of facilities used by a telephone company to transport
signals between a central office , roughly similar to a cable TV
headend, and a customer location.
|
|
Local Origination
|
Programming produced by a local cable system for presentation on the
system. It may also include syndicated programming acquired by the
system.
|
|
Low Noise Amplifier (LNA)
|
A low noise signal booster used to amplify the weak signals received
on a satellite antenna. Usually found in the receiver front ends.
|
|
Low Pass Filter (LPF)
|
Replaces the regular filter (used for one way transmission) on a
drop, and enables a subscriber to have 2-way service. The LPF allows
low frequencies to pass, but blocks out higher frequencies.
|
|
Low Power Television
|
Broadcast medium that is similar to commercial TV but limited in
broadcast coverage area by its low power signal.
|
|
Low Split
|
When upstream frequencies are assigned below 54 MHz.
|
|
MAC Address
|
An address identifies a particular medium access control (MAC)
sublayer service access point.
|
|
Master Antenna Television (MATS)
|
Antenna and distribution system which serves multiple dwelling
complexes such as hotel, motels and apartments.
|
|
MCNS
|
Multimedia Cable Network System - A consortium of CableLabs and
North American multi-system operators that developed DOCSIS, a
specification for the transmission of data over a cable network that
has been approved by the ITU as an international standard.
|
|
Medium Access Control (MAC) Protocol
|
In a subnetwork, that part of the protocol that governs access to
the transmission medium, independent of the physical characteristics
of the medium , but taking into account the topological aspects of
the subnetworks in order to enable the exchange of data between
nodes.
|
|
MegaHertz (MHz)
|
One million cycles per second.
|
|
Microwaves
|
High frequency radio waves used for telecommunications transmission,
usually above 890 MHz. Microwave frequencies require direct
line-of-sight to operate. Trees and buildings distort or block the
signal.
|
|
Microwave Oscillator
|
A device used to generate a microwave signal. it consists of two
parts:
- a resonator to control the frequency of the microwave
signal, and an active device to generate the power.
|
|
Mid Split
|
When upstream frequencies are assigned above 100 MHz.
|
|
Miles of Plant
|
The number of cable plant miles laid or strung by a cable system.
|
|
Mixer
|
A nonlinear circuit that produces an output at the sum and
difference frequencies of an applied fixed or variable oscillator
called the LO, and the RF input signal of interest.
|
|
Modem
|
Also Modulator/Demodulator - A device that converts digital signals
to analog or converts analog to digital, allowing computer data to
be carried over normal telephone and cable lines.
|
|
Modulation
|
When some characteristics of an electromagnetic wave are
deliberately changed or manipulated for the purpose of transmitting
information.
|
|
Modulator
|
A device that takes the video signal and audio signal that are
separated by the receiver and combines them into a signal that can
be received by an ordinary TV set.
|
|
Mode
|
The path a photon takes in going from one end of an optical fiber to
another.
|
|
Monitor Plus
|
A spot monitoring service provided by Nielsen which records both
local broadcasts and national cable commercial activities.
|
|
Monomode
|
Also Single-mode Fiber - All photons take the same path down the
center of the core of an optical fiber.
|
|
MPEG-2
|
Motion Picture Expert Group - a set of protocols designed for
encoding, compressing, storing and transmitting audio, video and
data in digital form.
|
|
Multiple System Operator (MSO)
|
A company that owns and operates more than one cable system.
|
|
Multicast
|
A multicast is a message that is sent out to multiple devices on the
network by a host.
|
|
Multiple Subnyquist Sampling Encoding
|
MSSEThe Japanese analog system using more than 6 MHz per channel.
|
|
Multiplexer
|
A device that allows several users to share a single circuit. It
funnels different data streams into a single stream. At the other
end of the communications link, another multiplexer reverses the
process by splitting the data stream back into the original streams.
|
|
Multiplexing
|
Transmitting multiple signals simultaneously on a single chain.
|
|
Multimode
|
When a photon careens off the optical fiber wall as it goes from one
end to the other. Other photons take different paths. There are
approximately 200 different paths in a single fiber.
|
|
Must-Carry
|
The FCC rule requiring cable systems to carry all local broadcast
television signals in their market.
|
|
National Television Systems Committee (NTSC)
|
The standard TV format for North America television transmission is
named after this standards committee; the format is 525 lines in a 4
MHz video bandwidth. All Tv set sold in N. America are compatible.
|
|
Narrowband
|
Generally refers to delivery channels capable of carrying sub T1
speeds.
|
|
NCTA
|
National Cable & Telecommunications Association - The major trade
association for the cable television industry.
|
|
Near Video On Demand (NVOD)
|
Also called Advanced PPV or Enhanced PPV - Provides a consumer with
a movie, or TV program, on a rotating schedule, thus giving the
appearance of an on-demand system.
|
|
Network Congestion
|
A state of overload within a network, where there is a risk of
traffic loss or service degradation.
|
|
Network Interface Unit (NUI)
|
Also called NID (Network Interface Device) - The NIU serves as the
point of demarcation between the local exchange carrier network and
the customer premise. The NIU is usually placed outside the main
body of the premise, on an exterior wall.
|
|
Network Layer
|
In open system interconnection (OSI) architecture, the layer that
provides services to establish a path between open systems with a
predictable quality of service.
|
|
Network Management
|
Within IEEE 802, the functions related to the management of the data
link layer and the physical layer resources and their stations
across the IEEE 802 LAN or MAN.
|
|
Network Operations Center (NOC)
|
A large group which is responsible for the day-to-day operations and
maintenance of a network.
|
|
Network Termination
|
Part of the Access Network, (owned by the carrier or the subscriber)
located on the side of the subscriber's home. The following are
functions of the Network termination
- Coupling of home wiring to
the carrier wiring
- Grounding
- RF Filtering
- Splitting
- Media conversion
- Remodulation Security and interdiction
-
Provisioning
- Loopback testing by the carrier
|
|
New Entrant Carrier (NEC)
|
This term is generally applied to new providers of competitive local
exchange telephone services.
|
|
Node
|
An addressable unit in a network, which can be a computer, work
station or some type of communications control unit.
|
|
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.
|
|
Number Portability
|
A capability that permits telecommunications users to maintain the
same telephone access number as they change telecommunication
suppliers.
|
|
OHM
|
The standard unit of resistance, reactance and impedance. A
resistant of 1 ohm will conduct 1 ampere of current when a voltage
of 1 volt is placed across it.
|
|
On-demand Service
|
A type of telecommunication service in which the communication path
is established almost immediately in response to a user request
brought about by means of a user-network signaling.
|
|
Optical Fiber
|
An extremely thin, flexible thread of pure glass, able to carry one
thousand times the information possible with traditional copper wire.
|
|
Optical Overload
|
A condition of high input current that causes pulse width distortion
at the output of the TIA.
|
|
Packet
|
A series of bits containing data and control information, including
source and destination node addresses, formatted for transmission
from one node to another.
|
|
Pay Cable
|
Cable programming services for which subscribers pay an additional
fee above the basic cable service charge. Also called Premium Cable.
|
|
Pay Cable Unit
|
Each premium service to which a households subscribes is counted as
one unit.
|
|
Passive Component
|
A component that requires no external source of power for it to
function.
|
|
Pay Per View (PPV)
|
Pay television programming for which cable subscribers pay a
separate fee for each program viewed.
|
|
Peer Entities
|
Entities within the same layer.
|
|
Penetration
|
Ratio of the number of cable customers to the total number of
households passed by the system.
|
|
Per-Inquiry Advertising
|
Direct response advertising for which the cable network or system
running the commercial is paid based on the he number of responses
received rather than the air time used.
|
|
Personal Communications Services (PCS)
|
Digital networks deployed in cellular; like configuration at 1.8 GHz
to 2.2 GHz.
|
|
Phase
|
A relative quantity describing the time relationship between or
among waves having identical frequency. The complete wave cycle is
divided into 360 equal parts, called degrees of phase.
|
|
Phase Distortion
|
When the output of an amplifier fluctuates in phase, even though the
input does not, the circuit introduces phase distortion into the
signal.
|
|
Phase Modulation
|
When the information is impressed on a radio frequency signal by
varying its phase angle.
|
|
Photodiode
|
A semiconductor device that converts light to electrical current.
|
|
Photoresistor
|
A device that exhibits a variable resistance, depending on the
amount of the light that strikes it.
|
|
Physical Layer
|
Layer 1, the lowest layer of the OSI model, is implemented by the
physical channel. The Physical layer insulates Layer 2, the Data
Link layer, from medium-dependent physical characteristics such as
baseband, broadband or fiber-optic transmission. Layer 1 defines the
protocols that govern transmission media and signals.
|
|
Picture Element
|
One of many monochrome or color "dots" that make up a television
picture.
|
|
Plastic Optical Fiber (PoF)
|
A plastic cable used, for short distances only, as an alternative to
fiber optical cable. Although plastic is not as transparent as
glass, it is more malleable and less expensive. PoF is a possible
choice for indoor networking.
|
|
Point of Presence (POP)
|
The point where the inter-exchange carrier's responsibilities for
the line begin and the local exchange carrier's responsibility ends.
Location of a communications carrier's switching or terminal
equipment.
|
|
Point-to-Point
|
A circuit connecting two nodes only, or a configuration requiring a
separate physical connection between each pair of nodes.
|
|
Port
|
The physical connector on a device enabling the connection to be
made.
|
|
Power Amplifier
|
An amplifier that delivers a certain amount of alternating-current
power to a load. Used in audio-frequency and radio-frequency
applications.
|
|
Power Gain
|
An increase in signal power between one point and another. Used as a
specification for power amplifiers.
|
|
Power Transistor
|
A semiconductor transistor designed for power-amplifier applications
at audio and radio frequencies.
|
|
Premium Cable
|
Cable programming services for which subscribers pay an additional
fee above the basic cable service charge. Also called Pay Cable.
|
|
Public Access
|
A non-commercial channel set aside by a cable system for use by the
public, on a first come first serve, non-discriminatory basis.
|
|
Pull Mode
|
The delivery method in which a subscriber demands and receives data
from the provider.
|
|
Push Mode
|
A delivery method where the service provider transmits on a fixed,
predictable schedule, or in response to an event such as the
updating of data in the subscriber's database.
|
|
Q Factor
|
For a capacitor, inductor or tuned circuit, the Q factor, or Q, is a
figure of merit. The higher the Q, the lower the loss and the more
efficient the component.
|
|
Quality of Service (QoS)
|
The accumulation of the cell loss, delay, and delay variation
incurred by the cells belonging to a particular ATM connection.
|
|
Ranging
|
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 expanding and
contracting of cable that occurs during the day.
|
|
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.
|
|
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.
|
|
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.
|
|
Ring
|
A network topology in which the nodes are connected in a closed
loop. Data is transmitted from node to node around the loop, always
in the same direction.
|
|
Roadblocking
|
The practice of stripping commercials in designated time periods
across multiple cable channels. Can be an effective method for
catching channel surfers.
|
|
Residential Gateway
|
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.
|
|
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.
|
|
Response Time
|
The length of time between he occurrence of an event and the
response of an instrument or circuit to that event.
|
|
Return Path
|
or Upstream, or Reverse Path - The term used to describe traffic and
paths that go from the subscriber to the headend.
|
|
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.
|
|
Router
|
Hosts that are connected to more than one network and route messages
between them.
|
|
Satellite
|
An orbiting space station primarily used to relay signals from one
point on the earth's surface to one or many other points. A
geosynchronous or "stationary" satellite orbits the earth exactly in
synchronization with the earth's rotation and can be communicated
with using fixed non-steerable antennas located within the
satellite's "footprint".
|
|
Satellite Master Antenna Television System (SMATV)
|
Systems that serve a concentration of TV sets such as an apartment
building, hotel, ect., utilizing one central antenna to pick up
broadcast and/or satellite signals.
|
|
Scramble
|
To interfere with an electronic signal or to rearrange its various
component parts. in pay television, for example, the signal though
ne scrambled, and a decoder, also called a descrambler, might be
necessary for the signal to be unscrambled so that only authorized
subscribers would receive the clear signal.
|
|
Service Consumer System (SCS)
|
The DAVIC term for the in-home infrastructure for broadband
networking. The SCS consists of the following
- The Network
Interface Unit (NIU), usually a modem
- The Residential Gateway
(RG), which adds network functionality and multiplexes different
services
- The Set-Top Unit (STU), which performs
applications-specific functions such as decoding digital TV
- The
Terminal Equipment (TE), which is a television, a PC or any other
device.
- Consumer premises distribution (wired or wireless)
|
|
Service Data Unit (SDU)
|
Information that is delivered as a unit between peer service access
points.
|
|
Shared Wired Network
|
A topology where multiple households connect to a common piece of
wire.
|
|
Second Audio Program
|
In A BTSC-encoded television sound carrier, a monaural audio
subcarrier that can be used to transmit supplemental foreign
language translation audio or other information.
|
|
Set-Top Box
|
A part of the Network Access which performs application-specific
functions such as decoding digital TV.
|
|
Share
|
The percent of television households tuned to a particular program
or category of programming.
|
|
Signaling
|
The process by which an end system notifies a network that it wants
service.
|
|
Signal Leakage
|
Undesired emission of signals out of a cable television system.
|
|
Signal to Noise Ratio (SNR)
|
The sensitivity of a communications receiver is generally specified
in terms of the audio signal-to-noise ratio that results from an
input signal of a certain number of microvolts.
|
|
Simple Network Management Protocol (SNMP)
|
Allows a TCP/IP host running an SNMP application to query other
nodes for network-related statistics and error conditions. The other
hosts, which provide SNMP agents, respond to these queries and allow
a single host to gather network statistics from many other network
nodes.
|
|
Skin Effect
|
The behavior whereby electricity migrates to the outside wall of a
wire.
|
|
Splitters
|
Passive devices that divide the traffic on trunk cables and send it
down feeder cables.
|
|
Spot Revenue
|
Revenue from advertising placed on a cable system by a local or
national a advertiser.
|
|
Spread Spectrum
|
Enables the successful transmission to hostile transmission
environments.
|
|
Staggercast
|
This term is used to designate the interval of time, in NVOD; that
is, the time between the beginning of a movie or program, on one
channel and the beginning of the same program on another channel.
(Ex: A movie starts at 7:00 on channel 50, at 7:15 on channel 51, at
7:30 on channel 52 - the movie is stagercast 15 minutes).
|
|
Store and Forward
|
Technique for examining incoming packets on an Ethernet switch or
bridge whereby the whole packet is read before forwarding or
filtering takes place. Store and forward is a slightly slower
process than cut-through, but it does insure that all bad or
misaligned packets are eliminated from the network by the switching
device.
|
|
Subscriber
|
A household or business that legally receives and pays for cable
and/or pay television service for its own use.
|
|
Subsplit
|
A frequency division scheme that allows bi-directional traffic on a
single cable. Return path signals come to the headend from 5 to 30
MHz. Forward path signals go from the headend from 54 to the upper
frequency limit.
|
|
Superband
|
The band of cable television channels J through W lying between 216
and 300 MHz.
|
|
Superstation
|
Originally referred to television station WTBS in Atlanta; now
generally used to describe any broadcast TV station that has its
signal distributed nationally by satellite.
|
|
Switch
|
A mechanical or electric device that is used to deliberately
interrupt, or alter the path of the current through the circuit.
|
|
Switched Network
|
Any network in which switching is present and is used to direct
messages from the sender to the ultimate recipient. Usually
switching is accomplished by decocting and reconnecting lines in
different configurations in order to set up a continuous pathway
between the sender and the recipient.
|
|
System Integrators (SI)
|
Companies that provide installation of networking equipment and
possibly other services such as training or network management.
|
|
System Loss
|
Cable TV distribution systems are designed to compensate the cable
and device losses. The spacing between cable amplifiers can increase
as system losses are minimized through the proper choice of
connectors, cable and related hardware System losses are referred to
as a "dB OD cable" without reference to specific cable size or
device losses. Generally these losses are understood to be at the
highest operating frequency of the system.
|
|
Systems Management
|
Functions in the application layer related to the management of
various open systems interconnection (OSI) resources and their
status across all layers of the OSI architecture.
|
|
Systems Network Architecture (SNA)
|
IBM's layered protocols for mainframe communications.
|
|
System Operator
|
The individual, organization, company or other entity that operates
a cable TV system.
|
|
Take Rate
|
The ratio of homes that pay for a cable service to homes passed.
|
|
Tap
|
A tap is a device which splits off a portion of the feeder line
signal for the subscriber.
|
|
Telco
|
Telephone Company - Refers the a local exchange telephone carrier.
|
|
Telecommunications
|
Communicating over a distance through wire, radio, optical or other
electromagnetic means.
|
|
Teletext
|
Broadcast service using several otherwise unused scanning lines
(vertical blanking intervals) between frames of TV pictures to
transmit information from a central data base to receiving
television sets.
|
|
Television
|
The electronic transmission and presentation of pictures and sounds.
|
|
Television Receiver-Only (TVRO)
|
The receiving antenna dish, or complete package or dish receiver.
|
|
Terminal
|
Generally, connection point of equipment, power or signal. Any
"terminating" piece of equipment such as computer terminal.
|
|
Thickwire
|
Half-inch diameter coax cable.
|
|
Thinwire
|
Thin coaxial cable similar to that used for television/video hookups.
|
|
Time Division Multiplexing Access (TDMA)
|
A digital technology that enables a large number of users to access,
in sequence, a single radio frequency channel without interference
by allocating unique time slots to each user within each channel.
|
|
Threshold
|
The minimum level at which a signal of any kind can be detected,
either by the human senses or by using any electronic instrument.
|
|
Throughput
|
The amount of data transmitted between two points in a given amount
of time, e.g., 10 Mbps.
|
|
Tiering
|
Supplying cable subscribers with one or more program services beyond
the basic offerings at an extra charge. Each additional price
increment is called a tier.
|
|
Token
|
The character sequence or frame, passed in sequence from node to
node, to indicate that the node controlling it has the right to
transmit for a given amount of time.
|
|
Token Ring
|
Developed by IBM, this 4 or 16 Mbps network uses a ring topology and
a token-passing access method.
|
|
Topology
|
The arrangement of the nodes and connecting hardware that comprises
the network. Types include ring, bus, star and tree.
|
|
Total Activity Report (TAR)
|
A quarterly Nielsen report which lists all the television activity
during a sweep including broadcast stations, PBS, basic cable, pay
cable, and superstations. it shows household rating and share
delivery by depart in both the DMA (total market) and cable
household universe for all program sources.
|
|
Traffic Parameter
|
A parameter for specifying a particular traffic aspect of a
connection.
|
|
Transceiver
|
A combination of a transmitter and a receiver having a common
frequency control and usually enclosed in a single package.
Extensively used in two-way radio communications at all frequencies.
|
|
Transducer
|
A device that converts one form of energy or disturbance into
another. transducers convert AC and DC into sound, radio waves, or
other forms.
|
|
Transimpedance
|
The transfer function of a TIA, the output voltage divided by the
input current.
|
|
Transistor
|
A semiconductor device consisting of three or four layers used for
switching or amplification at frequencies ranging from
direct-current to ultrahigh.
|
|
Translator
|
Relay system that picks up distant television signals, converts the
signals to another channel to avoid interference, and retransmits
them into areas that the original television signal could not reach.
|
|
Transmission Amplifier (TIA)
|
A devise used to convert input currents to output voltages.
|
|
Transmission Control Protocol/Internet Protocol (TCP/IP)
|
Are the standard network protocols in UNIX environments. They are
almost always implemented and used together and called TCP/IP.
|
|
Transmit Delay
|
The time difference between the instant at which the first bit of a
PDU crosses one designated boundary and the instant at which the
last bit of the same PDU crosses a second designated boundary.
|
|
Transmission Link
|
The physical unit of a subnetwork that provides the transmission
connection between adjacent nodes.
|
|
Transmission Medium
|
The material on which information signals may be carried, such as an
optical fiber, coaxial cable and twisted-wire pairs.
|
|
Transmission Systems
|
The interface and transmission medium through which peer
physical-layer entities transfer bits.
|
|
Transponder
|
The part of a satellite that receives and transmits a signal.
|
|
Trunk Amplifiers
|
The amplifiers along the trunk line responsible for maintaining
signal strength must have low distortion, low noise and moderate
gain. Degradation of the signal along the trunk cannot ne corrected
down stream, in fact, cascade amplifiers with similar faults simply
amplify the fault too. trunk amplifiers compensate for cable losses
with automatic slope control (ASC) and automatic gain control (AGC).
|
|
Trunk Cable
|
Cables that carry the signal from the headend to groups of
subscribers.
|
|
Trunk Line
|
Radiating out from the headend are trunk lines which carry the main
CATV signal to be distributed.
|
|
Trunking
|
Transporting signals from one point to another.
|
|
Typical Operating Conditions
|
Optimum operating conditions for a stated number of channels.
|
|
Ultra High Frequency (UHF)
|
Channels above channel 13 (or from 470 MHz to 806 MHz).
|
|
Unbundling
|
The separation and discrete offering of the components of the local
telephone service. Unbundling of network components facilitates the
provision of pieces of the local network, such as local switching
and transport, by telephone company competitors.
|
|
Unspecified Bit Rate (UBR)
|
The UBR service class is intended for delay-tolerant or
non-real-time applications, or those which do not require tightly
constrained delay and delay variation.
|
|
Upconverter
|
A device used to add a lower frequency to a microwave frequency.
|
|
Upstream
|
or Reverse Path or Return Path The term used to describe traffic and
paths that go from the subscriber to the headend.
|
|
V-Chip (Violence Chip)
|
A term used to describe a microchip which will permit parental
control over rated television programs.
|
|
Value-Added Reseller (VAR)
|
Refers to distributors that also provide other services such as
systems integration or network management.
|
|
Variable Bit Rate (VBR)
|
A type of telecommunications service characterized by a service bit
rate specified by statistically expressed parameters that allow the
bit rate to vary within defined limits.
|
|
Very High Frequency (VHF)
|
Channels 2-13 (54 - 88 MHz and 174 - 216 MHz).
|
|
Very Small Aperture Terminal (VSAT)
|
Small earth stations with a satellite dish usually 4-6 feet in
diameter used to receive high speed data transmissions; can also
transmit slow-speed data.
|
|
Video
|
A term pertaining to the bandwidth and spectrum of the signal which
results from television scanning and which is used to produce a
picture.
|
|
Video Dialtone
|
The means by which telephone companies may provide transmission
facilities and for on-telco video programming as well as certain
enhanced services to third-party programmers.
|
|
Video On Demand (VOD)
|
Allows the end-user subscriber to select movies they wish to view
from a large selection of titles and categories stored on a remote
server at any time. Service may also provide VCR functionality,
(stop, pause etc. which allows the end-user subscriber to control
the "play back" of the server from the remote control.
|
|
Videotex
|
The generic term used to refer to a 2-way interactive system for the
delivery of computer-generated data into the home, usually using the
television set as a display device. Some of the more often used
specific terms are "viewdata" for telephone-based systems
(narrowband interactive systems); "wideband broadcast" or
"cabletext" for systems utilizing a full video channel for
information transmission; and "wideband 2-way teletext" for systems
which could be implemented over 2-way cable television systems. in
addition, hybrids and other transmission technologies, such as
satellite, could be used for delivery of videotext services on a
national scale.
|
|
Viewers Per Viewing Household (VPVH)
|
A demographic percentage which indicates how many persons per 100 or
per 1000 households are viewing. For example, a VPVH of 80 K2-11
means that for every 100 households viewing, there are an estimated
80 children ages 2 to 11.
|
|
Virtual Channel (VC)
|
The communication channel that provides for the sequential
unidirectional transport of ATM cells.
|
|
Wide Area Network (WAN)
|
A computer network which usually spans larger geographic area, such
as cities, counties, states, nations and planets. WAN's usually
employ telephone-type topologies, like T1, T2, T5, ATM, ect. The
Internet is held together by lots of WAN's which hold together
LAN's, which network computers.
|
|
Wireless Cable
|
Uses microwaves frequencies to transmit programming to a small
antenna at a subscribers home.
|
|
Zero Cells
|
A phenomenon common to local market cable television ratings. The
Nielson household meter indicates viewing, but the corresponding
diary data shows no record of viewing.
|
|
|
|
