A

Active

• A powered electronic device that alters in some way the signal presented to it.

Aerial

• In cable broadband, it is a reference to plant facilities hung on poles.

AFC

• Automatic Frequency Control

Agile

• A device capable of user frequency selection as opposed to being fixed in frequency.

AGC

• Automatic Gain Control

AM

• Amplitude Modulation

AML

• Amplitude Modulated Link

Amplifier

• A device used to increase the strength of the signal supplied to it.

Analog

• A descriptor for quantities varying continuously rather than in discrete steps.

Anchor

• In aerial construction, a buried metal structure to which guy wires are tied.

Antenna

• A device designed to collect or emit electromagnetic energy.

APL

• Average Picture Level

Array

• An arrangement of antenna elements or antennas for increasing the strength of desired signals while reducing the strength of undesired signals.

ATSC

• Advanced Television Systems Committee

ASC

• Automatic Slope Control

Aspect Ratio

• Picture width to height (4:3 for NTSC and 16:9 for ATSC)

Attenuation

• The loss of signal through transmission often expressed in decibels.

Attenuator

• A device that is used to weaken the strength of the signal supplied to it.

Audio

• A reference to electronically reproduced sound or the equipment processing it.

Aural Carrier

• In analog television, the portion of channel radio energy carrying the sound.

B

Back Porch

• A reference to that part of the video signal immediately following the horizontal sync pulse.

Bandpass Filter

• A device that passes a range of frequencies while blocking frequencies outside that range.

Bandwidth

• The useable range of frequencies of a given device or system.

Baseband

• The originating signal information before it is modulated onto a radio frequency carrier.

Beamwidth

• The angular width at which an antenna's receive or transmit capability drops to half power.

Beats

• Undesired sum and difference frequency products created in an electronic device from two or more signals which can interfere with the desired signal.

Blacker-than-Black

• Below reference black level (sync pulse direction) in a composite video signal.

Black Level

• The brightness of black (peak) in a video signal (referenced in NTSC as 7.5 IRE).

Blanking

• That part of the video signal where the amplitude and timing renders retrace as invisible.

Block Converter

• A device that shifts a group of frequencies to a higher or lower grouping.

Block Tilt

• Tilt in broadband plant achieved by stepped signal levels of groups of frequencies.

Breezeway

• That part of the video signal between the sync pulse and the color burst.

Bridger

• In cable broadband, it is the amplifier that is fed from the trunk and, in turn, feeds the distribution plant.

Broadband

• In general, a large frequency capacity electronic device; in particular, a closed large capacity interactive electronic distribution system of multiple services to subscribers.

Broadcast

• An open, limited frequency capacity electronic transmission serving the public.

C

C-Band

• A satellite delivery system using a 3.7 - 4.2 GHz downlink.

Cable Modem

• A device used at the subscriber household to receive and transfer data at high speeds.

CARS

• Community Antenna Relay Service and Community Antenna Relay Station.

CATV

• Community Antenna Television; more commonly known as cable television.

Carrier or Carrier Wave

• An electromagnetic wave that is dynamically altered in order to convey intelligence.

Cascade

• Two or more amplifiers used in series to perpetuate an electronic signal.

CLI

• Cumulative Leakage Index

Coaxial Cable

• A broadband cable with a center conductor, insulating dielectric, and an outer shield.

Color Burst

• In NTSC, a few cycles of the 3.58MHz color subcarrier imposed on the composite video signal back porch as a reference.

Co-Channel Interference

• Interference created on a channel by a distant channel on the same frequency.

Combiner

• A isolating passive device used to combine differing channel outputs into a single output.

Composite Video Signal

• The complete video signal including blanking, synchronization, and color information (if used).

Converter

• A frequency changing device of which the most commonly known version is the customer set-top box.

Core Shrink-back

• When the center conductor of a coaxial cable or the entire cable itself pulls out of a connector due to temperature related contraction, also known a "suckout".

Cross Modulation

• A type of distortion where modulation from a channel or channels is superimposed onto another channel when they pass through a non-linear circuit.

CRT

• Cathode Ray Tube

Cycle

• A complete change in a waveform from zero to a negative peak to zero, then to a positive peak and back to zero.

D

dB

• Decibel, a unit relating the ratio of two signal levels using a logarithmic scale.

dBm

• Decibel Milliwatt.

dBmV

• Decibel Millivolt.

DBS

• Direct Broadcast Satellite.

dBW

• Decibel Watt.

Demodulator

• An electronic device used to remove the intelligence riding a carrier wave so that it may be displayed or processed.

Diplexer

• In broadband, a device that combines or splits differing frequency carriers.

Dipole

• A one-half wavelength center fed antenna consisting of two radiating elements.

Direct Pickup

• Undesired broadcast station ingress from the air and into the cable television system or customer equipment

Directional Coupler

• A passive device used to divide signals with the "through" port experiencing minimum loss, the "tap" port having a greater specified loss, and a high isolation loss between these ports.

Dish

• A reference to a parabolic antenna commonly designed for use at microwave frequencies.

Distortion

• Undesired changes in a signal waveform caused by the inherent nonlinearities of active devices and other processing elements of the transmission system.

Distant Signal

• A television broadcast signal that is received outside of its Grade B contour.

DLP

• Digital Light Processing

DOCSIS

• Data Over Cable Service Interface Specification

Downlink

• The signal transmission from a satellite to an earth station.

Downstream

• The signal flow direction in a CATV system when it travels from the headend to the service subscriber.

Drop

• The cable line connecting the subscriber household to the distribution plant of their broadband services supplier.

E

Earth Station

• The antenna and associated electronic equipment needed for satellite communications.

Effective Height

• The height of a antenna from ground in terms of its center of radiation rather than its physical location.

ERP

• Effective Radiated Power

Egress

• In cable broadband, it is the undesired leakage of signals from the plant into the air.

EIA

• Electronics Industries Association

Electrical Length

• In regard to performance, it is the effective length of an electrical device such as an antenna or transmission line (often expressed in wavelengths) rather than the physical length.

Electromagnetic Spectrum

• The entire range of frequencies at which energy may be electromagnetically radiated which includes everything from subaudible frequencies to gamma ray frequencies.

Encoder

• A device used to alter a signal so that it cannot be readily used unless another device (decoder) is authorized to do so.

Encryption

• The act of applying algorithms or coding to information so that it cannot be used without the proper "keys" to do so.

Equalization

• The application of frequency response devices to an electronic system to compensate for the frequency related losses of that system.

Equalizer

• In cable broadband, a passive device designed with a frequency response tilt opposite of the inherent response tilt in the cable that precedes it.

F

FDM

• Frequency Division Multiplexing

Feeder Cables

• In a cable broadband system, it is the intermediate lines of distribution that carry the signals from the main trunk lines to the subscriber lines.

Field

• One-half of a complete frame of video with each half being composed of either odd or even scan lines.

Field Strength

• Also known as Field Intensity, it is the strength of a radio wave at a given point.

Filter

• A passive device used to shape, pass,or block the frequency response of the signal fed to it.

Flooding Compound

• A viscous material placed within a cable to guard against water infiltration.

FM

• Frequency Modulation

Footcandle

• A measurement unit of illumination where 1 lumen is equally distributed across 1 square foot.

Footprint

• The area of earth covered by a satellites directed beam.

Forward Direction

• In cable broadband, the direction of signal flow from the headend to the subscriber.

Frame

• A single complete video picture composed of the odd scan line field and the even scan line field interlaced together.

Franchise

• Legal authorization issued by the local governing body (usually city, but can be county or state) to build and operate a cable television system in that jurisdiction.

Frequency

• The cycles-per-second count of a given audio or radio wave

Frequency Response

• The signal amplitude gain/loss across the frequency bandwidth of a given device or transmission system.

Frequency Suckout

• A sharp signal loss or notch within a device or system's passband.

FSK

• Frequency Shift Keying

Front Porch

• The part of the video synchronization signal that follows the picture information and precedes the horizontal sync pulse.

Funny Paper Effect

• The misregistration seen on video when the chrominance information either leads or lags the luminance information.

G

Gain

• Usually expressed in decibels, it is the increase in signal strength through an amplifying device when comparing the output value to the input value.

Geostationary

• A satellite that is in an orbit that allows travel that is synchronized with the earth's rotation, thus creating a constant "stationary" relationship.

Geosynchronous

• See "Geostationary".

Group Delay

• The difference in transmission time between frequency elements passing through an electronic device or medium.

Guard Band

• Radio frequency spectrum left unused between channels in order to avoid interference.

H

Harmonic Distortion

• Unwanted frequency multiples of the frequency fundamental(s) that are generated due to the nonlinearities of an electronic device.

HDMI

• High Definition Multimedia Interface

HDTV

• High Definition Television

Headend

• The central electronics facility of a cable broadband system where all signal sources are generated, gathered, processed, combined, and fed into the trunking/distribution system.

Heterodyne

• To electronically mix two frequencies together in a nonlinear device in order to produce two new frequencies equal to the sum and difference of the originating frequencies.

High Band

• The band of frequencies covering 174MHz to 216MHz where channels 7 to 13 reside.

High Pass Filter

• A filter that attenuates all frequencies below a designated cutoff point and passes all frequencies above that point

Home Theater

• A recreation of the cinema experience in the home that can range from simple multichannel sound and large screen enhancements to the construction of theater staging and seating.

HRC

• Harmonically Related Carriers

Hub

• A signal processing facility located between the headend and the signal distribution system in order to provide customized regional services.

Hue

• The dominant optical wavelength that causes visual perception to distinguish a particular color apart from others.

Hum

• In audio, it is a low pitched interference tone often picked up from AC power sources, while in cable broadband it is often a reference to visual Hum Modulation.

Hum Modulation

• The undesired modulation of the visual carrier by power line frequencies and harmonics (or other low frequency disturbances) sometimes visible as bars rolling through the picture.

Hyperband

• For CATV, the band of frequencies above 300MHz.

Hz

• Hertz, a measure of frequency known formerly as "cps" or "cycles-per-second" but renamed in honor of Heinrich Rudolph Hertz who furthered the understanding of electromagnetic waves.

I

IF

• Intermediate Frequency

Impedance

• The total resistive and reactive opposition to the flow of an alternating current signal at a given frequency.

Impulse Noise

• Short duration transient disturbances.

Inductor

• A coiled conductor designed to oppose changes in current by virtue of its concentrated magnetic field.

Infrared

• The section of electromagnetic spectrum just below visible light.

Ingress

• The undesired influx of interference into a cable broadband system from sources outside of the system.

IRC

• Incrementally Related Carriers

Isolation

• The attribute of a device that minimizes signal transfer from one point to an inappropriate point.

J

Jitter

• An unstable picture usually caused by disturbances to synchronization.

Jumper Cable

• In cable broadband, it is a short length of coaxial cable used to connect close proximity devices such as a converter box and the customer television.

K

Ku Band

• The band of microwave frequencies extending from 12 to 18GHz (in North America, the reference commonly refers to the 11.7 to 12.2GHZ satellite downlink portion).

L

LASER

• Light Amplification by Stimulated Emission of Radiation

Lasher

• A machine used in aerial construction to tie the communications lines to the support strand by spin-wrapping wire around the cable bundle.

LCD

• Liquid Crystal Display

LCoS

• Liquid Crystal on Silicon

Leakage

• Undesired signal emissions from a cable broadband system (often from cable cracks or poor connections) into the air.

LED

• Light Emitting Diode

Line Extender

• An amplifier used in the distribution system of cable broadband to extend the reach of the signal.

Line-of-Sight

• An unobstructed path through open space intended for transmit/receive stations such as point-to-point microwave, satellite-to-earth transmissions, and optical laser links.

LNA

• Low Noise Amplifier

LNB

• Low Noise Block Converter

LNC

Low Band

• The band of frequencies covering 54MHz to 88MHz where channels 2 to 6 reside.

• Low Noise Converter

Local Origination

• Programming produced and telecast from the local cable broadband provider.

Local Oscillator

• The oscillator in superheterodyned equipment that generates the proper frequency signal needed to mix with the received signal to produce the desired intermediate frequency.

Local Signals

• Television broadcast signals received within their respective Grade B contours.

Log Periodic Antenna

• A directional antenna with the radiating elements and spacing arranged in logarithmically increasing dimensions in order to provide wideband reception or transmission.

Low Pass Filter

• A filter that attenuates all frequencies above a designated cutoff point and passes all frequencies below that point

Lumen

• The unit of light flux from a point source of one candle through a unit solid angle.

Luminance Signal

• The part of the television signal that carries the brightness information and can produce a complete monochromatic picture.

M

Makeready

• The process in cable broadband where the readiness of underground and poleline facilities are ensured prior to construction.

MATV

• Master Antenna Television System

MDS

• Multipoint Distribution System

MCR

• Master Control Room

Messenger

• Refers to either the supporting steel strand to which hardline coaxial cable may be lashed or the supporting steel wire embedded in the jacket of aerial coaxial drop cable.

Microwave

• A reference to those radio waves with a frequency above 1000MHz.

Mid Band

• The band of frequencies covering 120MHz to 174MHz where cable television channels 14 to 22 (A to I) reside.

Midspan

• A point on the strand and coaxial distribution cables located between two utility poles.

MMDS

• Multichannel Multipoint Distribution

Modulate

• To alter a constant carrier wave's amplitude, frequency or phase by impressing a varying intelligence wave onto it.

Modulation

• The electronic process used to impress intelligence onto a carrier wave for transportation to a distant recovery location.

Monitor

• A term usually applied to a television, a speaker, or other studio equipment used in observing the quality of signal and can also apply to the act of observance itself.

MTS

• Multichannel Television Sound

N

NAB

• National Association of Broadcasters

NCTA

• National Cable Television Association

Noise

• Random electron movement in an electronic circuit that influences the desired signal passing in that circuit.

Noise Figure

• The expected amount of noise in decibels added by a given electronic signal processing circuit.

Noise Temperature

• A noise contribution rating derived by positing the temperature of a resistor connected to an ideal amplifier compared to the actual amplifier were it connected to a resistor at 0K.

Notch Filter

• A filter designed to pass all frequencies except for that at which it is tuned to attenuate.

NTC-7

• Network Transmission Committee guidelines for the placement of test signals in the vertical interval of an NTSC television signal for testing transmission performance.

NTSC

• National Television System Committee

O

Off-air

• Used interchangeably with the term "off-the-air", it denotes signal reception taken off an antenna after passing through the air.

Operating Power

• From the viewpoint of a transmitting antenna, it is the actual power supplied to it.

Optical Fiber

• A glass or plastic fiber designed to propagate light for the purpose of information transmittal.

Oscilloscope

• An electronic testing device designed to graphically display changes in voltage with respect to the passage of time.

P

Pan

• A slow horizontal movement of a camera while restricting vertical movement.

Parabolic Dish Antenna

• A center fed high gain antenna with a parabola derived dish shape that is used for satellite, microwave, and other short wavelength electromagnetic communications signals.

Passband

• A band of frequency spectrum typically defined by half power boundaries that is allowed to pass through a device that attenuates the remainder of the spectrum.

Passive

• A non-powered electronic device that alters in some way the signal presented to it.

PPV

• Pay-Per-View

PCM

• Pulse Code Modulation

Peak-to-Peak

• The measurement of a varying electrical signal from its highest amplitude excursion to its lowest excursion.

PEP

• Peak Envelope Power

PLL

• Phase Lock Loop; Phase Locked Loop

Pilot Carrier

• In CATV, it refers to the carrier waves used as references by system devices to allow automatic compensation adjustments of carrier amplitudes either equally or by relative frequency.

Pixel

• A "picture element" which is the smallest point of a raster image.

Preamplifier

• A low noise amplifier designed to precede another amplifier.

Pressure Tap

• From historic CATV, it was a obsolete device used to tap the distribution cables without completely cutting the line when installing a customer drop line at a new location.

Propagation

• The act of an electromagnetic wave traveling through space or a medium.

PSA

• Public Service Announcement

Public Access Channel

• Government mandated television channel space granted by a cable television company for public use by citizen programmers.

Q

QAM

• Quadrature Amplitude Modulation

R

Radiator

• The element of an antenna fed by signal line so it may propagate an electromagnetic signal.

Radio Frequency

• The band of electromagnetic spectrum that today stretches from 3 KHz to 300 GHz.

Random Noise

• Molecular activity in a material that generates non-coherent electrical disturbances.

Raster

• A pattern of scan lines (analog) or pixels (digital) that form a picture on a display device.

Rectifier

• An electronic device that converts alternating current into direct current.

Resolution

• The amount of detail that can be seen on a television screen as described by the number of distinct lines that can be resolved.

Return Loss

• The ratio of reflected power to transmitted power in decibels for a given device inserted into a transmission line..

Ring Network

• A closed communications loop where each node of the loop is connected to two other nodes.

RMS

• Root Mean Square

Roll-off

• A term used to describe a steepness of loss of signal vs frequency at the passband edges of a circuit or transmission system.

S

SAP

• Secondary Audio Program

Satellite

• In communications, it is a spacecraft that orbits the earth to relay signals over great distances from one location to another.

SAW filter

• Surface Acoustic Wave filter

SBE

• Society of Broadcast Engineers

SCA

• Subsidiary Communications Authority

Scramble

• In pay television, it is a method of disrupting the presentation of programming except for paying customers.

SCTE

• Society of Cable and Telecommunications Engineers

Second Harmonic

• A signal generated at twice the frequency of its originating fundamental frequency.

Second Order Beat

• A distortion product created by the mixing of two signals due to the non-linearities of an electronic device.

Sheath Current

• Improper electrical energy that travels on the shield of a coaxial cable.

Sidebands

• Lower and upper frequency bands of energy created by the modulation of a carrier wave.

Signal Leakage

• In CATV, it is the electronic signals that escape from the confines of the closed system and into the air.

Signal-to-Noise Ratio

• It is the ratio measured in decibels of desired signal to undesired background noise.

Sine Squared Pulse

• It is a video test signal used in bandwidth limited systems to evaluate performance issues such as chrominance to luminance errors.

Single Channel Antenna

• An antenna with elements designed primarily for one channel of interest rather than a band of channels.

SLM

• Signal Level Meter

Slope

• In CATV, it is the change in gain with respect to frequency across the bandwidth of the system.

SMATV

• Satellite Master Antenna Television

SMPTE

• Society of Motion Picture and Television Engineers

Spectrum Analyzer

• An electronic device which reveals the graphical dispersion of energy in a display of frequency vs amplitude.

Splitter

• A device that divides the electronic signal at it input to allow more than one output.

Spurious Signals

• Undesired signal energy present at any frequency at the output of a device that was not present at the input.

SRL

• Structural Return Loss

Stacked Array

• In communications, it refers to a stacked antenna array which is a group of antennas physically arranged and connected to increase gain and directivity.

Standby Power Supply

• In CATV, it is a step-down transformer with a battery backup meant to power the electronic devices in the branches of the system.

Star Network

• A network where a central node processes communication between all other nodes.

STL

• Studio-to-Transmitter

Strand

• The steel wire used to support the coaxial cable in CATV and other closed communication systems.

Strip Amplifier

• A single channel amplifier used by MATV systems and small CATV systems to stabilize broadcast channels before placing them in the system.

Studio

• A facility designed to enable the creation of audio and/or video productions.

Sub Band

• The band of frequencies in the 5MHz to 50MHz range where cable television channels T7 to T13 reside and is typically used for reverse or upstream signals.

Subcarrier

• A carrier wave, itself modulated with intelligence, that is modulated onto another carrier.

STV

• Subscription Television

SCA

• Subsidiary Communications Authority

Super Band

• The band of frequencies in the 216MHz 300MHz range where cable television channels 23 to 36 (J to W) reside.

Superheterodyne

• A common circuit in receivers today that mix the incoming signal with a locally generated one to create a more easily processed intermediate signal.

Sync

• It is abbreviation for the synchronization signal used to lock the timing of the scanned video to allow a picture be recreated on a television screen.

T

Tap

• A passive electronic device placed in the distribution lines of a cable television system to feed signal to the household drop line.

TASO

• Television Allocation Study Organization

TBC

• Time Base Corrector

Teleconference

• A meeting where the presence of participants at different locations are brought together virtually by audio and video.

Television

• An electronic device capable of displaying realtime or recorded moving pictures and sound from distant or nearby sources.

Terminal Isolation

• In CATV, it is the attenuation in decibels between the subscriber's terminal and another terminal in the system.

Terminator

• An impedance matched device used to terminate a CATV port.

Thermal Equalizer

• A electronic device used in a cable television system to compensate for changes in line loss during varied temperatures.

Third Harmonic

• A signal generated at three times the frequency of its originating fundamental frequency.

Third Order Beat

• A distortion product created by the mixing of three signals due to the non-linearities of an electronic device.

Tilt

• In CATV, it is the difference in amplifier gain or cable loss between the lower passband edge and the upper passband edge.

TDM

• Time Division Multiplexing

TDR

• Time Domain Reflectometer; a device that provides a pulse to a line under test and allows the reflected pulse to be graded in amplitude and distance on a graphical display.

Transponder

• That part of a satellite that relays communications to and from earth stations.

Trap

• An electronic filter used at cable television subscriber taps to prevent passage of certain channels.

Traveling-wave Tube

• A high power amplifying tube used in microwave applications.

Triple Beat

• A distortion product created by the mixing of three signals due to the non-linearities of an electronic device.

Trunk Amplifier

• In CATV, it is an amplifier used in the main trunk lines to compensate for line loss.

TVRO

• Television Receive Only; a reference to a satellite earth station that receives satellite signals, but cannot transmit to it.

Twinlead

• An obsolete form of television wiring that is composed of two parallel wires and insulation jacket in a flat ribbon form.

Two-way

• A reference to a cable system that not only sends signals into the system, but receives them as well.

U

UHF

• Ultra High Frequency

Uplink

• A communications transmission from an earth station to a satellite

Upstream

• The signal flow direction in a CATV system when it travels from the service subscriber to the headend.

V

VCR

• Video Cassette Recorder

Vectorscope

• A specialized test instrument designed to check gain and phase of a chrominance signal.

Velocity of Propagation

• The speed of a signal transmission in a medium relative to the speed of light in a vacuum.

VBI

• Vertical Blanking Interval

VITS

• Vertical Interval Test Signals

Vestigial Sideband

• An amplitude modulated carrier with one sideband truncated to improve power efficiency.

VHF

• Very High Frequency

VHS

• Video Home System

Visual Carrier

• In television, it is the carrier modulated with the luminance information

VTR

• Video Tape Recorder

VSWR

• Voltage Standing Wave Ratio

VU

• Volume Unit

W

Waveform Monitor

• A specialized test instrument designed to check various video waveform levels with respect to time.

Wavelength

• Inversely proportional to its frequency, it is the distance traveled by a sinusoidal wave when it completes one complete cycle.

White Clipper

• A video circuit designed to prevent excessive video levels from generating interference on the audio portion of the television signal.

XYZ

Yagi

• A directional antenna commonly composed of a dipole, a parasitic reflector, and one or more parasitic directors.

Zoom

• A term used to denote the ability to adjust the lens angle of view to change the perceived distance to the subject matter.