Digital signal processing—This is used with digital as opposed to analog audio
and video signals.
Distribution amplifiers—Distribution amplifiers take a single audio input,
amplify it, and distribute it to multiple audio outputs.
In many deployments of audio visual systems more than one sound source
exists and an audio mixer is needed to combine or mix the multiple signals.
For example, if there were three panelists speaking at a conference each with
his or her own microphone, the mixer would combine and adjust the individ-
ual signals as needed. After the processing and combining the audio signal
may be routed to a set of speakers, possibly using an amplifier in-between.
Mixers are used in recording and broadcast studios (mixing boards), but
can also be part of a public address system and audio visual systems for large
meeting rooms. Mixers have various features such as the ability to add effects
to the sound and connections for a personal computer to provide enhanced
equipment management.
Like audio signals, video signals also need to be processed, adjusted and
“groomed.” The processing of video signals is, however, significantly different
than audio as the amount of information for video signals is magnitudes
greater than that of audio. Video processing may involve amplifying or adjust-
ing the timing, color, brightness, or contrast of the signal. Video processing
equipment can include time base correctors to maintain the integrity of the sig-
nal and video processing amplifiers.
Audio and video signals both require devices to switch and route signals.
An audio visual switcher is a “traffic-cop” type of device with the ability to
connect a signal input to a single output connection. A matrix switcher or
router is just multiple switches with the capability to switch multiple inputs
to multiple outputs.
Video switches are primarily used in video production and distribution. For
example, a live event such as a football game can be covered by several cam-
eras and a video production switcher allows production personnel to easily
switch between cameras. A matrix switcher may be used with a video distribu-
tion system within a building allowing for different video sources to be routed
to different areas or rooms within a facility.
The amplification of audio and video signals increases the voltage and
power for further distribution of the signal before delivery to its destination.
Video distribution amplifiers typically take a signal output, amplify it to main-
tain signal quality, then distribute it to multiple outputs. A room having mul-
tiple displays where one video signal is to be distributed to all available
displays will use a video distribution amplifier.
Audio Visual Systems 173