Delayless Subband Echo Cancellation
|Document type:||Conference Papers|
|Author(s):||Sven Nordholm, Jörgen Nordberg|
|Title:||Delayless Subband Echo Cancellation|
|Conference name:||Fifth International Congress on Sound and Vibration ICSV'5|
|Organization:||Blekinge Institute of Technology|
|Department:||Dept. of Signal Processing (Institutionen för signalbehandling)
Dept. of Signal Processing S-372 25 Ronneby
+46 455 38 50 00
|Abstract:||Echo suppression is a vital part of every communications system. The use of hands-free communication in cars, computer applications and video conferencing have created further demands for high-quality acoustic echo cancellation. In these applications the acoustic channel has, typically, a long impulse response in the order of 100 ms. Typical lengths of adaptive FIR-filters are 500-1500 taps, assuming a 12 kHz sampling frequency. In order to reduce the computational load and also to improve the convergence rate, sub-band processing schemes have been suggested.
This paper presents a study of a delayless sub-band adaptive filter. The study shows a possible echo suppression of about 30 dB and also an improved convergence rate when compared to a fullband LMS-filter. The main issues discussed are filter bank design and a simple speech detector that gives a drastic performance improvement.
|Keywords:||Echo cancelation, Multi-rate|