VOICECRAFTER
TM
GENERAL INFORMATION
28
11. GENERAL INFORMATION
11.1
GLOSSARY OF ECHO
CANCELING TERMS
Acoustic Coupling - Loudspeaker signal
which is picked up by the microphone(s).
Acoustically Dead - A conference room
environment with surfaces which reflect
very little sound. Such environments
contain surfaces such as sound absorbing
panels, curtains, carpeting, etc.
Acoustic Echo Return Loss (AERL) - The
amount of signal attenuation which occurs
naturally between the loudspeaker and the
microphone(s).
Ambient Noise - Background noise in the
conference room environment due to air
conditioning/heating equipment, factory
noise, highway noise, etc.
Barrel Effect - A ‘hollow’ sounding signal,
caused by microphones picking up signal
which is reverberating within a room.
Bassy - Pronounced signal strength in the
lower frequency ranges.
Bridge – Interconnection of conference
systems from multiple locations.
Clipping - Signal which is incomplete due to
portions being cut in the process of
transmission.
Codec - A device which produces a coded
output from an analog input and vice versa.
Convergence – Echo canceller adaption to
changes in the conference environment.
Dead Zone - The area in a conference
room not covered by a microphone,
because it is outside the active pickup
pattern of the microphone.
Disable - To turn off.
Double Talk - Speech which occurrs
simultaneously at more than one
conference location at the same time.
EC ASIC - A proprietary, integrated circuit
that performs echo cancellation.
Echo - Signal coupling which occurs
between loudspeakers and microphones
located within the same conference room.
Echo Canceller - An adaptive filter that is
capable of recognizing echo, on a
transmission line, and subtracting it from
the near end speech signal.
Echo Return Loss Enhancement (ERLE) -
The attenuation applied to the echo signal,
by the adaptive filter of the echo canceller.
Enable – To turn on.
