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Appendix A • Reference Information
Extron • Matrix 3200/6400 Series • User’s Manual
Glossary of terms
Following is a list of terms taken from Extron’s Glossary.
AC – Alternating Current – Flow of electrons that changes direction alternately.
ADA – Extron’s product designation for Analog Distribution Amplifier.
AMPS – Amperes – A unit of measurement for current.
Analog – Analogue – A continuous signal that takes time to make a transition from one
level to another. Standard audio and video signals are analog. This signal has an
infinite number of levels between its highest and lowest value. (Not represented by
bits, such as with digital.)
ANSI – American National Standards Institute
ASCII – American Standard Code for Information Interchange – The standard code
consisting of 7-bit coded characters (8 bits including parity check), utilized to
exchange information between data processing systems, data communication
systems, and associated equipment. The ASCII set contains control characters and
graphic characters.
Attenuation – The decrease in magnitude of a signal.
Audio Follow – A term used when audio is tied to other signals, such as video, and they
are switched together. (The opposite of Break-away)
Balanced Audio – A method that uses three conductors for one audio signal. They are
plus (+), minus (-) and ground. The ground conductor is strictly for shielding, and
does not carry any signal. Also Differential Audio.
Bandwidth – A frequency range, or “band” of frequencies, within which a device
operates. In audio and video, it is the band of frequencies that can pass through a
device without significant loss or distortion. The higher the bandwidth, the sharper
the picture; low bandwidth can cause a “fuzzy” picture.
Barrel – Outward curved edges on a display image. Also see “pincushion”.
Blanking – The turning off of the electron beam that scans the image onto the screen.
When the beam completes a scan line it must return (retrace) back to the left. During
this time, the beam must be turned off (horizontal blanking). Similarly, when the last
line has been scanned at the bottom of the screen, the beam must return to the
upper left. This requires vertical blanking.
Blooming – Most noticeable at the edges of images on a CRT, “blooming” is when the
light (color) is so intense that it seems to exceed the boundary of the object. Thin
lines and sharp edges could look thick and fuzzy. This may be caused by the
brightness being set to high, or by a high voltage problem.
BNC – It is a cylindrical Bayonet Connector which operates with a twist-locking motion.
Two curved grooves in the collar of the male connector are aligned with two
projections on the outside of the female collar. This allows the connector to be locked
in place without the need of tools.
Break-away – The ability to separate signals for the purpose of switching them
independently. For example: an audio and video signal from the same source may
be “broken away” and switched to different destinations. This is the opposite of the
term “follow”.
Buffer – Generally referred to as a unity gain amplifier used to isolate the signal source
from the load. This is for both digital and analog signals.
Cable Equalization – The method of altering the frequency response of a video amplifier
to compensate for high frequency losses in cables that it feeds. (See Peaking.)
Capacitance – The storing of an electrical charge. At high frequencies, capacitance that
exists in cables also represents a form of impedance.
Cathode Ray Tube – See CRT.
Chroma – The characteristics of color information, independent of luminance intensity.
Hue and saturation are qualities of chroma. Black, gray, and white objects do not
have chroma characteristics.
Chrominance Signal – Part of a television signal containing the color information.
Abbreviated by “C”.
Coaxial Cable – A two-conductor wire in which one conductor completely wraps the
cable.
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