Chapter 13 Flashcards
1
Q
Amplitude
A
The magnitude of a signal. When
represented as a wave, it
represents the intensity of the wave
or the distance of the wave’s
displacement from the midline.
TDMM.* Page 13-3
2
Q
ER
A
Equipment Room
1 .An environmentallv controlled
centralized space for
telecommunications equipment that
usually houses a main or
intermediate cross-connect. (TIA)
2.An environmentally controlled space
for communications and data
processing equipment supporting
communications connectivity
infrastructure.
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3
Q
Frequency
A
The number of cycles in a given
time period. Measured in hertz
or cycles per second.
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4
Q
Harmonics
A
Higher frequency waves blended
with fundamental waveforms.
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5
Q
LED
A
Light-Emitting Diode
A semiconductor diode that
spontaneously emits incoherent
light from the p-n junction when
forward current is applied. It
converts information from
electrical to optical form. An LED
typically has a large spectral width.
LEDs are commonly used with
multimode optical fiber.
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6
Q
Phase
A
A waveform’s position in time
compared with another
waveform. Expressed in degrees,
with 360 degrees representing
one complete cycle of the
wavelength.
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7
Q
Wavelength
A
The distance in between two
corresponding points of two
consecutive cycles.
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8
Q
Name the 4 basic, but essential elements, of audiovisual (AV) design and integration.
A
- The hardware or the physical electronics connected together
- The software or programs loaded into the electronics to perform various AV tasks
- The environment or the space and infrastructure within which the hardware and software work.
- The content, which includes video, audio, and data material created and
presented using the available software and hardware
TDMM: Page 13-1
9
Q
What term is used to
describe the action of
molecules pressing close
together?
A
Compression
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10
Q
What is a wavelength?
A
The distance in between two
corresponding points of two
consecutive cycles
TDMM.* Page 73-2
11
Q
What term refers to the
magnitude of a signal?
A
Amplitude
TDMM.* Page 13-3
12
Q
How does the human ear
perceive amplitude
of a sound?
A
As loudness or volume
TDMM.* Page 13-3
13
Q
What is the relationship
between the amplitude of a
sound wave and
volume/loudness?
A
The greater the amplitude of
sound wave, the louder
the sound.
TDMM.* Page 13-3
14
Q
How is loudness
measured?
A
In decibels of sound
pressure level (dB SPL)
TDMM.* Page 13-3
15
Q
What is the dynamic range
of hearing for humans?
A
From the threshold of hearing to
the threshold of pain
(O to 120 dB SPL)
TDMM.* Page 13-3
16
Q
What term is used to
express a waveform’s
position in time compared
with another waveform?
A
Phase
TDMM.* Page 13-4
17
Q
How is a phase expressed?
A
In degrees, with 360 degrees
representing a complete cycle of
the wavelength
TDMM.* Page 13-4
18
Q
What does it mean if a
wave is said to be 180
degrees out of phase with
another signal?
A
That one wave is at its
maximum pressure point and
the other is at its minimum
pressure point
TDMM.* Page 13-4
19
Q
What phenomenon
can occur when two
mics close to each
other pick up sound at
different times?
A
Comb filtering
TDMM.* Page 13-4
20
Q
How is frequency
measured in most cases?
A
Hertz (Hz) or cycles per second
TDMM.* Page 13-5
21
Q
What is heard as a pure
tone or note?
A
Simple single sine waves
TDMM.* Page 13-5
22
Q
What is the fundamental
waveform?
A
A sine wave
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23
Q
What type of waveform
determines the sound
quality?
A
A complex waveform
TDMM.* Page 13-5
24
Q
What are harmonics?
A
Higher frequency waves blended
with fundamental waveforms
TDMM.* Page 13-6
25
What is wave-particle
duality?
The two theories of light, where
one theory states that light, like
sound, is made of waves of
energy and the other theory
states that light is made of
small particles called photons
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26
How are waves of energy
categorized?
By their wavelengths
TDMM.* Page 13-7
27
What part of the
electromagnetic spectrum
can the human eye see?
A small section of the
electromagnetic spectrum that
can be seen by the human eye
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28
What determines the color
of a light wave?
The frequency
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29
What color is at the center
of the visible light
spectrum?
Green
TDMM.* Page 13-8
30
How is the amplitude of a
light wave perceived by the
human eye?
As brightness
TDMM.* Page 13-8
31
How does amplitude affect
the brightness of a
light wave?
The greater the light wave's
amplitude, the larger the wave's
displacement from the midline
and the light's brightness.
TDMM.* Page 13-8
32
Why do light waves have
different tints?
Because they have different
distributions of color
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33
What is color temperature?
A scientific measurement for the
distribution of the colors
radiating from a light source,
which is expressed on the
Kelvin scale
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34
What is the basis of the
Kelvin scale as applied to
properties of light?
The color of light emitted when
substance is heated
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35
What temperatures are
perceived as white?
3200 K
5400 K
6500 K
9300 K
TDMM.* Page 13-9
36
What is the color
temperature of candlelight?
1900 K
TDMM.* Page 13-9, Table 13.1
37
What is the range of color
temperature for a
tungsten lamp?
3200 to 3400 K
TDMM.* Page 13-9, Table 13.1
38
What is the color temperature for daylight, at noon with a cloudless sky?
Daylight: 5400 K
Noon: 5500 K
TDMM.* Page 13-9, Table 13.7
39
The higher the temperature,
the ___ the light.
The higher the temperature, the bluer the light.
TDMM.* Page 13-9
40
The lower the temperature,
the ___ the light.
The higher the temperature, the redder the light.
TDMM.* Page 13-9
41
What type of signals do
humans produce and
hear naturally?
Analog signals
in the form of sound
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42
What is the only real
restriction to modern audio
technology?
The human ear
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43
What is the typical range of audio frequencies used by most audio equipment?
10 Hz to 30 kHz
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44
True or False
Modern AV systems no longer involve the use of analog signals.
False. Even though AV
equipment is predominantly
digital, AV systems will typically
involve the use of analog audio
signals. Such components may
include microphones, speakers,
mixers, and analog signal
amplifiers.
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45
Name 3 audio level
categories.
1 .Microphone
2.Line
3.Speaker
TDMM.* Page 13-10
46
Name the 2 typical types of line levels.
1. Professional (+4 dBu)
2. Consumer (-10 dB referenced to 1 V [dBu])
TDMM.* Page 13-10
47
What are the three
connection points for a
balanced audio circuit?
1 .Conductor carrying the signal
just as it originated (+)
2.Conductor carrying the same
signal with opposite polarity (-)
3.Electrical ground (usually the
shield)
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48
What makes a balanced
circuit?
When the two signal conductors
have the same impedance
relative to ground
TDMM.* Page 13-11
49
What is benefit of using
balanced circuits?
They provide for a higher quality
signal with less noise over long-
distance cable runs.
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50
Name 2 disadvantages
associated with balanced
circuits.
1 .Expensive to manufacture
2. Time-consuming to terminate
TDMM.* Page 13-17
51
Why do microphone levels
need to be balanced?
Because their extremely
low level requires the best
possible connection
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52
What is the sampling rate?
The number of times a sample
is taken per second
TDMM.* Page 13-12
53
What does the Nyquist
frequency represent?
The highest frequency of the
analog signal being recorded. It is
equal to half of the sampling rate.
TDMM: Page 13-12
54
What is bit depth?
The number of bits that
describe a signal value
TDMM: Page 13-13
55
What is the resolution of a
digital audio signal?
The range of numbers that can
be assigned to each sample
TDMM.* Page 13-73
56
What is quantization noise?
The error between the actual
analog signal value and the
digitized value
TDMM.* Page 13-13
57
What bit resolution is commonly used with Internet voice devices?
8 bit
TDMM.* Page 13-74, Table 13.3
58
What bit resolution is commonly used with audio digital versatile
discs?
24 bit
TDMM.* Page 13-74, Table 13.3
59
Name the 3 primary
standards for analog video.
1 .NTSC
2.PAL
3.SECAM
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60
What term describes the
process of coordinating the
signal information with
respect to time?
Synchronization (sync)
TDMM.* Page 73-16
61
Name 3 signals needed to create a complete a video image.
1 .Horizontal sync
2.Vertical sync
3.RGB
TDMM.* Page 13-15
62
What term is used to describe
the process that occurs in a
cathode ray tube (CRT),
where an electron beam
moves in a sequenced and
ordered manner, charging
phosphors?
Scanning
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63
What term refers to the
range of frequencies that
can pass through a
medium?
Bandwidth
TDMM.* Page 13-17
64
What is the bandwidth of
human vision?
430 to 750 trillion Hz
TDMM.* Page 13-77
65
How is bandwidth
assessed in electronics?
In terms of frequency of
voltage rather than light
TDMM.* Page 13-17
66
What will happen when
electronic frequencies fall
out of a circuit's
bandwidth?
The frequencies will no
longer be detected.
TDMM.* Page 13-77
67
How does composite sync
affect signal stability?
Composite sync reduces
signal stability.
TDMM.* Page 13-78
68
True or False
All full-bandwidth signals
are too robust to be readily
handled by most
processing equipment.
True. All full-bandwidth signals
are too robust to be readily
handled by most processing
equipment.
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69
What is a method of
creating bandwidth-limited
signals that combines the
sync information with the
signals for brightness?
Luminance or luma (Y)
TDMM.* Page 3-19
70
Human perception of light is most sensitive to the ___ spectrum of light.
Human perception of light is
most sensitive to the
yellow/green spectrum of light.
TDMM: Page 3-79
71
Human perception of light is least sensitive to the ___ spectrum of light.
Human perception of light
is least sensitive to the
blue spectrum of light.
TDMM.* Page 3-19
72
How does the color
encoder or matrix
create the Y?
It strips the brightness
information from the RGB
signals and adds it up
to make the Y.
TDMM.* Page 13-79
73
Why is component video
used extensively in the
production environment?
Because of its quality
and lack of artifacts
TDMM.* Page 13-79
74
What is an RF video?
A composite video with two
audio channels
TDMM.* Page 13-21
75
Name 5 common digital
video interfaces.
1 .Digital video interface (DVI)
2.High-definition multimedia
interface (HDMI)
3.DisplayPort
4.Serial digital interface (SDI)
5.HDBaseT
TDMM.* Pages 13-22 to 13-24
76
Name the 3 primary digital
television (DTV) standards.
1 .lntegrated services digital
broadcasting
2.Digital video broadcasting
3.Advanced Television Systems
Committee standard
TDMM.* Page 13-25
77
Where is the integrated
services digital broadcasting
standard used?
Japan
TDMM: Page 13-25
78
Where is the digital video
broadcasting standard
used?
Europe, Australia, and Asia
TDMM.* Page 13-25
79
Where is the ATSC
standard used?
North America
TDMM: Page 13-25
80
What is the aspect ratio for
SDTV programs?
4:3
TDMM.* Page 13-26
81
What is the aspect ratio for
HDTV programs?
16:9
TDMM.* Page 13-26
82
What is serial
communication?
A form of data communications
where information is sent
sequentially, one piece at
a time, down a cable
TDMM.* Page 13-26
83
What is the limit for cable
length per RS-232
specifications?
A maximum cable length of
-15.2 m (50 ft)
TDMM.* Page 13-27
84
What would happen if the
settings for an RS-232
device were incorrect?
The device would no longer be
controllable, even with only
one incorrect setting.
TDMM.* Page 13-27
85
Why are RS-422 cable runs
able to be longer than
RS-232 cable runs?
Because RS-422 is balanced
TDMM.* Page 13-27
86
What is the advantage of
using RS-485 serial
communications
over RS-422?
The RS-485 signal supports
multiple devices on
the same line.
TDMM.* Page 13-28
87
What is the communications
protocol used for computer
networking technologies over
the Internet?
Transmission control
protocol/lnternet protocol
(TCP/lp)
TDMM.* Page 13-28
88
Are IR controls one-way or
two-way devices?
One-way
TDMM.* Page 13-28
89
How do contact closures
communicate?
Through changes in
current or voltage
TDMM.* Page 13-29
90
How many external devices
can a single IEEE 1394
device support?
Up to 63
TDMM.* Page 13-29
91
What is the maximum
bandwidth for USB 3.2?
SuperSpeed (20 Gb/s)
TDMM.* Page 13-29
92
Why are dark wall colors
used in projection rooms
and movie theaters?
To absorb unwanted
ambient light
TDMM.* Page 13-30
93
What is the recommended
aspect ratio to use when
sizing presentation
spaces?
2:1
TDMM: Page 13-31
94
What is the optimum
viewing angle?
45 degrees horizontally to
each side of the center axis
of the display
TDMM.* Page 13-32
95
What dictates the seating layout for a communications space?
AV sightlines
TDMM: Page 13-32
96
What is the average seated
head height?
1.2m (4 ft)
TDMM.* Page 13-33
97
What is the average seated
eye height?
1.07m (3.5 ft)
TDMM.* Page 13-33
98
How are sightlines
arranged in a single-row
vision seating layout?
In single row vision, the vertical
sightline of a viewer passes over
the heads of the persons in the
first row ahead.
TDMM.* Page 13-34
99
How are sightlines
arranged in a double-row
vision seating layout?
In double-row vision, the vertical
sightline passes between the
heads of the persons in the first
row ahead and over the heads of
the persons in the second
row ahead.
TDMM: Page 13-35
100
What is millwork?
Ready-made and custom fit
woodwork such as installed
cabinetry, credenzas, shelving,
doors, and baseboards
TDMM.* Page 13-36
101
True or False
All electronic equipment
produces heat.
True. All electronic equipment produces heat. Any device that produces heat will have a heat load.
TDMM.* Page 13-36
102
What is contrast ratio?
A ratio between the projected
image and the ambient light
condition at the image location
TDMM.* Page 13-38
103
Name 3 advantages of
liquid crystal displays
(LCDs).
1 .More robust in terms of long-
term performance
2.Resistant to image burn-in
3.Ability to re-lamp the LCD
display for greater product
longevity
TDMM: Page 13-38
104
What is the most common
disadvantage associated
with LCDs?
No true black level, which
adversely affects the color
rendition
TDMM.* Page 13-38
105
What makes LEDs ideal for
outdoor applications even
under daylight conditions?
Their extreme brightness
TDMM.* Page 13-39
106
What is the most common
disadvantage associated
with organic light-emitting
diode (OLED) displays?
The limited lifespan of the
organic materials
TDMM.* Page 13-39
107
Name the 2 general
categories of projection
display solutions.
1 .Front projection
2.Rear projection
TDMM.* Page 13-39
108
Which project display
solution is the most
commonly used today?
Front projection
TDMM.* Page 13-39
109
True or False
Typically, a rear projection
space becomes an ER.
True. Typically, the rear projection
space becomes an ER with space
allocated for supporting equipment
racks, installed video cameras, IR
emitters, wireless microphone
antennae, or audio loudspeakers.
TDMM.* Page 13-41
110
What are the two basic
types of loudspeaker
systems?
1 .Program systems
2.Reinforcement systems
TDMM: Page 13-44
111
Which type of
loudspeaker system
contains no microphones
and is used strictly for the
reproduction of recorded
or transmitted audio?
Program system
TDMM.* Page 73-44
112
Name the 3 main categories
of audio materials.
1 .Vocal range
2.Full range
3.Extended range
TDMM.* Page 13-44
113
What are the 2 main
requirements for a program
audio system?
1 .Loud enough
2.Intelligible
TDMM.* Page 13-45
114
What performance criterion is
used to rate loudspeakers?
Sensitivity, which is expressed
as SPL
TDMM.* Page 13-45
115
Name the 3 main
requirements for a speech
reinforcement system.
1.Loud enough
2.Intelligible
3.Stable
TDMM.* Page 13-46
116
What is the design goal for a speech reinforcement system?
To ensure that audience members in the least favored
listening positions (i.e., the farthest from the talker) receive the same listening experience as the audience members closer to the talker.
TDMM.* Page 13-46
117
What are the 2 main
variations for speech
reinforcement systems?
1 .Point source (central cluster)
2.Distributed speech
TDMM.* Page 13-47
118
Which loudspeaker
placement method is
preferred for covering a
large area?
Point source
TDMM.* Page 13-48
119
How will placing speakers
more than *13.7 m (45 ft)
above the talker affect
the listeners?
The listeners who can hear
direct sound from the talker as
well as the reinforcement will
hear an echo or some distortion.
TDMM.* Page 13-48
120
For optimal distribution of the full range of important frequencies, overlap of as much as _ percent in adjacent loudspeaker distribution patterns is recommended.
For optimal distribution of the full range of important frequencies, overlap of as much as 50 percent in adjacent loudspeaker distribution patterns is recommended.
TDMM.* Page 13-51
121
What do matrix routing
switchers provide?
Connection of multiple inputs
to multiple outputs
TDMM: Page 73-53
122
Name 2 main reasons
matrix routing switchers
are not used in applications
for distribution.
1 .Cost
2.SignaI performance
TDMM.* Page 73-53
123
What is the purpose of
signal conversion?
To create compatibility of
signals for connection to
devices, switching and routing,
or specialty transmission
TDMM.* Page 13-53
124
Name 4 aspects to
consider when reviewing
the setup for a working
conference environment.
1.Type
2.Objective
3.Duration
4.Dynamics
TDMM: Page 13-54
125
What is the goal of
audioconferencing?
To enable two mutually distant
groups of people, referred to as
the local and remote talkers,
respectively, to communicate
with fast interaction and allow
both parties to speak and be
heard at the same time as if
they were physically in the
same room
TDMM.* Page 13-54
126
An NC 30 rating corresponds to approximately _ dBA SPL of background noise.
An NC 30 rating corresponds to 40 dBA SPL approximately of background noise.
TDMM.* Page 13-56
127
What has the largest impact on the audioconferencing quality?
The types and locations of microphones
TDMM.* Page 13-56
128
Why are directional
microphones the most
common choice for
conferencing systems?
*Rejection of the background
noise
*Reduction of
reverberation/multipath
*Rejection of the audio from the
loudspeakers
TDMM.* Page 13-57
129
Why are highly directional
microphones not typically
used in conferencing?
Because of the extremely
narrow pickup pattern
TDMM.* Page 13-57
130
What is the shape of the
pickup pattern for a
boundary microphone?
Half-spherical
TDMM: Page 73-57
131
What term is used to
describe the distance from
the microphone where the
reverberant sound field and
the direct sound field from
the local talker are equal
in intensity?
The critical distance
TDMM.* Page 13-58
132
What will happen to the
sound quality if the
microphone is placed
outside the critical
distance?
The resulting speech quality
would be considered poor,
characterized by a bottom-of-
the-barrel or muffled sound.
TDMM.* Page 13-58
133
Why is a lavalier style of
wireless microphone a
better choice than a
handheld wireless
microphone?
*Ensures that the microphone
stays a constant distance from
the talker's mouth
*Minimizes the sound level
variation to the remote
participants in a conferencing
application
TDMM.* Page 13-59
134
When should a ceiling
microphone be tested for
audio quality?
As early in the design
process as possible
TDMM.* Page 13-60
135
How much room space will
a ceiling microphone cover?
=9.3 m2 (100 ft2)
TDMM.* Page 13-60
136
What is the role of the
automatic microphone mixer?
To limit the number of open
microphones or contributing
audio at any given time to only
the microphones associated
with active talkers
TDMM.* Page 13-60
137
When do acoustic echoes
occur in audioconferencing
applications?
When an open-air acoustic path
exists between the local
loudspeaker and the local
microphone
TDMM.* Page 13-61
138
What is the most common
and reliable real-time
communication network for
audioconferencing?
PTSN
TDMM.* Page 13-63
139
True or False
Side-tone is desirable while
talking on a handset.
True. Side-tone is desirable
while talking on a handset;
however, it is not desirable in a
conferencing application.
TDMM: Page 13-64
140
What is required to properly
interface the telephone
hybrid to the local telephone
line characteristics?
A country code setting
TDMM.* Page 13-65
141
How is the loudspeaker
coverage angle defined?
By the angle where the
loudspeaker levels are within
6 dB of the on-axis level
TDMM: Page 13-65
142
What is the rule regarding
how far to distribute
loudspeakers?
Distribute the loudspeakers not
farther than twice the distance
from the ceiling to the
listener's ear level.
TDMM: Page 13-67
143
How are loudspeaker
power ratings expressed?
In decibels SPL at 1m (3.28 ft)
TDMM.* Page 13-68
144
What is the estimated
transformer loss for each
loudspeaker?
1 dB
TDMM: Page 13-69
145
Choose an amplifier at _ to _ percent larger than the sum of the required loudspeaker power.
Choose an amplifier at 25 to 50% larger than the sum of the required
loudspeaker power.
TDMM.* Page 73-69
146
Why should a videoconference
room be larger than a similarly
populated basic meeting
room?
Because the attendees must be
spaced apart, so the far-end
viewers can more easily see and
differentiate those attendees
TDMM.* Page 13-70
147
Where should the ICT
designer consider locating
a videoconference room?
In an interior room with ready
access to public spaces
in the building
TDMM.* Page 13-70
148
What noise criterion (NC)
guidelines are recommended
for videoconference room
needs?
NC 30
TDMM.* Page 13-70
149
Why should traditional long,
narrow boardroom tables
be avoided in any video-
enabled space?
*From the view at the far-end,
the scene will always appear to
be a difficult picture to watch,
especially with the unavoidable
obstruction of participants'
faces.
*Camera operation also is
compromised by this layout.
TDMM.* Page 13-71
150
What is the best color to
paint a wall that will be
detected by the camera for
a videoconferencing
system?
Medium gray with a blue tint
TDMM.* Page 13-71
151
Why must videoconference
cameras be collocated with
the far-end display?
To provide a sense
of eye contact
TDMM.* Page 13-72
152
How does increasing light
affect the depth of field?
More light equals a greater
depth of field.
TDMM.* Page 13-75
153
Name 3 lighting conditions
a camera will not tolerate.
1 .GIare
2.Wide differences in light levels
3.Lighting color variations
TDMM.* Page 13-76
154
What is the usual dynamic
range for videoconference
systems?
200:1
TDMM.* Page 13-76
155
What device is used to
convert analog and video
signals into digits?
Codec
TDMM: Page 13-76
156
True or False
Videoconference system
manufacturers provide
microphones that are often
adequate and should be used.
True. Videoconference system
manufacturers provide
microphones that are often
adequate and should be used.
TDMM.* Page 13-77
157
Name the 2 basic ISDN
variations for videoconferencing.
1 .BRI
2.PRl
TDMM.* Page 13-77
158
What is the primary
purpose of a remote
system for the AV system?
To integrate the operation of
various devices onto a single
control surface
TDMM.* Page 13-79
159
What term is used to
describe the control
surface of the remote
control system?
Graphical user interface (GUI)
TDMM.* Page 13-80
160
How is a voice page made?
By dialing a code or pressing a
button on a telephone and
making an announcement
TDMM.* Page 13-82
161
What are the 2 main
technologies employed in
paging systems?
1 .Centrally amplified systems
2.Distributed amplified systems
TDMM.* Page 13-83
162
Name 2 types of amplifiers
and loudspeakers that can
be used in centrally
amplified systems.
1 .Constant current
2.Constant voltage
TDMM.* Page 13-83
163
How do distributed amplifier
systems typically connect to
the telephone system?
Through a control unit located at
the headend equipment
TDMM.* Page 13-83
164
What is direct sound?
The sound that travels directly from a loudspeaker to the listener
TDMM.* Page 13-84
165
How is the ideal
distribution for a
loudspeaker system
accomplished?
By locating the loudspeakers in a
way that provides even coverage
at the lowest wattage possible
TDMM.* Page 13-84
166
What are the SPL
requirements for
a voice page?
At least 6 dB, but not more than
20 dB above the ambient
noise level
TDMM.* Page 13-84
167
What could happen to voice
pages if the 6 dB level is
not followed?
*May be lost in the ambient
noise of the room
*Will be unintelligible
TDMM.* Page 13-84
168
What will happen to voice
pages if the 20 dB ambient
noise level is not followed?
The paging will be far too
loud in areas closest to the
loudspeakers and horns.
TDMM.* Page 13-84
169
What are the 2 most
common loudspeaker
distribution patterns?
1 .Hexagonal
2.Square
TDMM.* Page 13-85
170
Why is a hexagonal
distribution pattern
preferred for loudspeaker
distribution?
Because it provides the most
uniform coverage
TDMM: Page 13-85
171
How far apart should
loudspeakers be placed in
a row if the area has a
noise level of less than
70 dB?
Approximately twice
the ceiling height
TDMM.* Page 13-86
172
Where should wall-
mounted loudspeakers
mounted?
=2.4 m (8 ft) to -3.7 m (12 ft)
above the floor
TDMM: Page 13-86
173
Where should the first
ceiling-mounted loudspeaker
in hallway be placed?
=2.4 m (8 ft) from
the end of the hall
TDMM.* Page 13-87
174
What does phasing
refer to when applied
to loudspeakers?
Phasing refers to whether the
diaphragms of two or more
loudspeakers are moving inward
or outward at the same times.
TDMM.* Page 13-88
175
When are loudspeakers in-phase?
When their diaphragms are
moving inward or outward
at the same time
TDMM.* Page 13-88
176
How do out-of-phase loudspeakers affect paging?
They reduce the overall sound
volume and quality in the area.
TDMM.* Page 13-88
177
What term describes an unwanted oscillation or tone that quickly grows in loudness?
Feedback
TDMM.* Page 13-88
178
What constant voltage
systems are commonly used?
*70 V system
*25 V system
TDMM.* Page 13-88
179
What is the purpose of a
sound masking system?
To provide a masking noise in
spaces where conversation may
be distracting or where
confidentiality of conversations
is important
TDMM.* Page 13-92
180
Name 3 major factors
that affect a sound
masking system.
1 . The office furniture orientation
and absorption
2.Rating
3. The ceiling tile NRC
TDMM.* Page 13-92
181
What is typically the largest
contributor to the reduction
of noise levels in the
open office?
The ceiling
TDMM: Page 13-92
182
What type of lighting
should be used in a space
that will use sound
masking?
Indirect or task lighting
TDMM.* Page 13-92
183
What is the measure of a
space's noise level?
Noise Criterion (NC)
TDMM: Page 73-92
184
To have a masking system
acceptable to those working
in the space, the NC should
not be higher than
To have a masking system
acceptable to those working in
the space, the NC should not be
higher than 35.
TDMM.* Page 13-92
185
Name the 4 common
components of a sound
masking system.
1 .Masking noise generator
2.Equalizer
3.Amplifier
4.Loudspeaker
TDMM.* Page 73-93
186
Describe pink noise.
Pink noise has equal energy
across the octave bands where
it produces noise.
TDMM.* Page 13-93
187
True or False
The same level of masking
must be used throughout
the facility.
False. Different levels of
masking may be required for
different types of areas in a
facility, including hallways,
lobbies, and restrooms.
TDMM.* Page 13-94
188
What A1 level denotes
no intelligibility?
0.00
TDMM.* Page 13-94
189
What A1 level denotes
perfect intelligibility?
1.00
TDMM.* Page 13-94
190
What articulation index
would predict a confidential
level of speech privacy?
0.00 to 0.04
TDMM.* Page 13-95, Table 13.8
191
How difficult is it to
eavesdrop in an
environment the provides
marginal privacy?
Not difficult. Marginal privacy
implies minimal speech privacy,
which means audible
conversations will be distracting
and eavesdropping will be easy.
TDMM.* Page 13-95
192
What is the best level of
privacy the ICT designer
can expect from a properly
designed sound masking
system in an open office?
Normal privacy
TDMM.* Page 13-95
193
Are conversations from
adjacent rooms intelligible
when confidential privacy
is present?
No. Conversations from adjacent
rooms are not intelligible when
confidential privacy is present.
TDMM.* Page 13-95
194
True or False
Total privacy cannot be
achieved with sound
masking alone.
True. Total privacy cannot be
achieved with sound masking
alone. Special construction
techniques are required to
achieve this level of privacy.
TDMM.* Page 13-95
195
What component binds the
DDS network together?
The software application
TDMM.* Page 13-97
196
Name 3 critical
components of a DDS.
1 .Content creation
2.Scheduling and distribution
3.PIayback
TDMM.* Page 13-98
197
What term refers to the
actual time a person is in
the location of the screen?
Dwell time
TDMM.* Page 13-99
198
Name 3 locations where
private cable systems are
typically found.
1 .Office buildings
2.Industrial facilities
3.Schools
TDMM.* Page 13-700
199
Name the 3 basic elements I
of a cable system.
1 .Headend
2.Distribution system
3.Subscriber drop
TDMM.* Page 13-700
200
What are the most
common types of coaxial
cable used in intrabuilding
CATV systems?
*Series-6
eSeries-11
*12.7 mm (0.5 in) hardline
Note: All are 75 ohm.
TDMM: Page 13-107
201
What is programming?
The video and audio material
that is broadcast over
a cable system
TDMM: Page 13-101
202
What type of coaxial cable
is recommended to carry
the signal from the antenna
to the distribution system?
75-ohm coaxial cable
TDMM.* Page 3-701
203
What is a satellite dish?
A parabolic antenna that
receives RF signals sent by
geostationary satellite
transponders
TDMM.* Page 13-701
204
How does the FCC define
CAT v feed?
A service through which
subscribers pay to have local TV
stations and additional
programs brought into their
homes from an antenna via
coaxial cable
TDMM.* Page 73-101
205
Name the 2 basic
topologies used in private
CATV distribution systems.
1 .Home run
2. Trunk and tap
TDMM.* Page 13-102
206
Which CATV topology is
generally the least
expensive means way to
serve an area?
Trunk and tap
TDMM.* Page 13-103
207
What type of device is used
to convert from 75-ohm
unbalanced coaxial to 100-
ohm balanced twisted-pair
cabling category 5e or
better?
Balun
TDMM.* Page 13-104
208
What length do most
manufacturers use as the
maximum distance
limitation between the
active component and the
TV or monitor?
90m (295 ft)
TDMM.* Page 13-704
209
Name 2 factors that must
be considered when
calculating losses for a
network design.
1 .Cable loss
2.Device loss
TDMM.* Page 13-706
210
What is a directional coupler?
A splitter with uneven outputs
TDMM.* Page 13-707
211
What is a combiner?
A device that has several inputs
and a single output, which
follows the same principles as a
splitter or directional coupler,
but in reverse
TDMM: Page 13-108
