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ECHO AND NOISE CANCELL ATION •
ECHO CANCELL ATION
10
Figure 5 shows a how a single echo canceller attempts to cancel echo in a room.
Audio from the distant room is sampled and used as a reference for the echo
canceller. When far-end audio is picked up by the microphone (acoustic echo),
the acoustic echo canceller senses the echo and builds an adaptive filter that
eliminates the echo.
Sample
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Audio from
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Echo Cancelled
Audio
Acoustic Echo
Microphone Mixer
Sample
Figure 5. Single Echo Canceller
The XAP 800’s Distributed Echo
Cancellation places an echo
canceller on each mic input for
dramatically improved echo
cancellation (see Figure 6).
In this example, audio from a
distant room is sampled. This
audio is a reference for each echo
canceller on every mic. When
sampled audio (acoustic echo) is
detected by the echo canceller,
the echo is eliminated.
Sample
Sample
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Audio from
Distant room
Echo Cancelled Audio to distant room
Acoustic Echo
Microphone Mixer
=Acoustic Echo Canceller
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Figure 6. Gentner’s Distributed Echo Cancellation
Summary of Contents for XAP 800
Page 1: ...XAP 800 White Paper ...
Page 67: ......
