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AEC - ACOUSTIC ECHO CANCELLATION TAB
Displays the input and output channels and the recorder player at the bottom. And, at the top, shortcuts to
the channels, the configuration of each channel and the main parameters of the AEC system module.
Configuration
AEC
Acoustic echo cancellation (AEC) is important when simultaneous communication (or full-duplex transmission)
of speech is required, e.g. for audio tele-conferencing.
A microphone signal contains two signals: the near (programme or local) speech signal and the far echoed
(reference or remote) speech signal. What the AEC aims to do is to eliminate the remote microphone signal
so that only the local microphone signal is transmitted.
AECs are not only useful in telephony applications; they can be used anywhere where it is necessary to
remove one (remote) signal from a second (local) signal. To help understand this we can think of an assistance
button in a public car park. The person providing assistance (remote) speaks into a microphone which is
reproduced by the loudspeaker of the person requesting assistance (local). Audio from the loudspeaker can
be reflected by the car park elements such as cars, luminaries, columns, floor, ceiling and walls; and enter
through the microphone. The person in attendance would hear his or her own words echoed back to him
or her. By implementing AEC, the attendant's remote audio can be extracted from the audio of the assisted
person's microphone, eliminating echo.
The parameters to be configured are:
-
LOCAL INPUT (1-32, AUTOMIXER): allows you to select the source(s) containing the desired audio signal
as well as the unwanted echo of the remote audio signal.
-
REMOTE INPUT (1-32, USB): selects the source(s) for the audio signal to be subtracted from the LOCAL
INPUT signal.
-
NLP - NON-LINEAR PROCESSOR: sets the TAIL TIME in NLP. The TAIL TIME is the time during which
the remote signal will be compared with the local signal and used for echo estimation. If the AEC has a
PNL value less than the length of the longest echo, the echo shall still be heard in the programme signal.
The values are:
falta acceso directo a canales
INPUT Channels
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OUTPUT Channels
Player/Recorder
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