CTS Certified

Glossary

577

transformer  A passive electromagnetic device commonly consisting of at least
two coils of wire (inductors) with no physical connection between them. Most often,
these coils share an iron-based alloy core. This common core aids in concentrating the
magnetic lines of force created by the current flow in one coil (primary), thereby induc-
ing a voltage into the other coil (secondary).

transient disturbance  A momentary variation in power, such as a surge, spike,
sag, blackout, or noise.

transmission  Passing of sound energy through partitions or structure-borne vibra-
tions.

transmissive technology  Any display device that creates images by allowing or
preventing light to pass.

TRS  Tip, ring, sleeve. A three-conductor design of a phone connector that can be
terminated as balanced or unbalanced.

TS  Tip, sleeve. A two-conductor design of a phone connector used for an unbalanced
circuit.

tweeter  A loudspeaker that is designed to reproduce frequencies above 3,000 Hz.

twisted-pair  Any number of wires that are paired together and twisted around
each other. The wires can be shielded or unshielded.

unbalanced circuit  A two-conductor circuit in which one conductor carries the
signal and the other conductor carries the return. The return conductor is usually the
cable shield and is a low-impedance connection, as it is connected to the signal ground
and possibly also to the earth ground. The impedance of the signal circuitry is quite
different from the return circuitry, hence the impedances of the two conductors are
quite different—the impedances are unbalanced with respect to one another.

unity gain  Derived from the number 1, refers to no change in gain.

UTP cable  Unshielded twisted-pair cable, typically used for data transfer. UTP cable
contains multiple two-conductor pairs twisted at regular intervals, employing no
external shielding.

V  See volt.

vectorscope  A specialized oscilloscope used in video systems to measure chromi-
nance accuracy and levels.

viewing angle  A viewing-area measurement that determines how far off-axis
(screen centerline) a viewer can sit and still see a good-quality image. This is no greater
than 45 degrees off the projection axis.

viewing cone  The best viewing area for the audience. The term cone is used because
there is width, height, and depth to the best viewing area, and this area emanates from
the center of the screen.

CTS Certified Technology Specialist Exam Guide

578

virtual local-area network (VLAN)  A network that connects separate LANs
to form a logical group. For instance, the LANs at each branch of a large company could
be combined into one company-wide VLAN.

virtual private network (VPN)  A network that uses the Internet to create
a tunnel between two or more local-area networks (LANs). VPNs are used to create
virtual wide-area networks (WANs), and for remote monitoring, troubleshooting, and
control. VPNs are typically controlled and configured by the enterprise network
administrator. Each host requires the proper software, access rights, and password to
log in to the client network.

volt (V)  The basic international unit of potential difference or electromotive force.

voltage  The electrical potential to create current flow in a circuit.

waveform monitor  A specialized oscilloscope used to display and analyze the
video signals synchronization, luminance, and chroma levels.

wavelength  The distance between two corresponding points of two consecutive
cycles measured in meters.

white noise  A sound that has the same energy level at all frequencies.

wide-area network (WAN)  A data communications system that uses telecom-
munication circuits to link local-area networks (LANs) that are distributed over large
distances. A WAN covers a large geographical area, such as a state or country. The Internet,
which covers the entire world, is an example of a WAN.

wire  A single conductive element intended to carry a voltage or electronic signals.

wireless local-area network (WLAN)  A network that shares information by
radio frequency (RF) transmissions.

woofer  A loudspeaker that has low frequencies, typically 20 to 200 Hz.

XLR connector  A popular type of audio connector featuring three leads: two for
the signal and one for overall system grounding. This is a secure connector often found
on high-quality audio and video equipment. It is sometimes called a cannon connector.

Y/C  A video signal, also known as S-Video. Y is the luminance, and C is the chromi-
nance. Y and C are transmitted on separate synchronized conductors.

zero reference  InfoComm experts consider this term ambiguous. See reference
point.

zoom lens  A lens that allows the operator to adjust the focal length for sizing or
distance.