ATEIS ECS - Manual (Page 22)

ECS MANUAL
Version EN.1
22
ACOUSTIC ECHO CANCELLATION (AEC)
ACOUSTIC ECHO EXPLANATION
In remote conference applications, reflected signals caused by acoustic echo between
microphones and speakers are normal, for example, when two people communicate with each other
in different places.
A's voice from the microphone will travel through the speaker in room B and reflect to the
microphone. It would result in acoustic echo. The acoustic echo usually appears when microphones
and speakers are in the same space. It can decrease the quality of the conversation.
The main idea of AEC is to simulate the impulse response of the echo path included space
reflection and time delay. According to this concept, the audio is sampled at the Far-End signal. AEC
applies the sampled signal 180 degrees out of phase with the Near-End signal to eliminate it. If the
simulation is meeting to the real echo signal, the echo will be deleted and not affect the voice of the
user. The following picture aims to eliminate the echo for user B. B will not hear her own voices from
the speaker.