PCS-XG100/XG77 System Integration Manual
Stereo echo canceller's learning principle
When there is only one sound source, the stereo echo canceller cannot learn four different
echo paths, because:
. The balance of the volume from each of the L and R channels is constant.
. The arrival time interval (Δt) between the sounds from the L and R channels is constant.
To achieve adequate learning by the stereo echo canceller, the sounds from multiple sound
sources of the remote party must reach the echo canceller. This is the essential difference
from the monaural echo
canceller. If all of the participants stay in their respective fixed positions and speak, however,
the stereo echo canceller can produce its maximum effect. If the speaker moves, the stereo
echo canceller learning process may take a long time and an echo may remain.