Title :
Nonlinear compensation for finite word length effects of an LMS echo canceller algorithm suitable for VLSI implementation
Author :
Song, Moon S. ; Yang, Paul P N ; Shenoi, Kishan
Author_Institution :
DSC Granger Assoc. Inc., Santa Clara, CA, USA
Abstract :
When an algorithm for echo cancellation is to be implemented in VLSI, it is essential to minimize the word length of the coefficients for economical reasons. While insufficient word length significantly degrades the performance of the canceller, it is possible to compensate for its effects by using a nonuniform number representation system, i.e. pseudo-floating-point arithmetic. Such an algorithm, using 10 bits, is discussed and its performance is compared with that of ordinary fixed-point algorithms with various number of bits. A multichannel echo-canceller chip has been built using this algorithm. It is used successfully in a T1 echo canceller system
Keywords :
VLSI; echo suppression; telephone equipment; LMS echo canceller algorithm; T1 network; VLSI implementation; echo cancellation; finite word length effects; least mean square algorithm; multichannel echo-canceller chip; nonlinear compensation; nonuniform number representation system; pseudo-floating-point arithmetic; telephone equipment; Adaptive filters; Arithmetic; Degradation; Delay; Echo cancellers; Equations; Filtering algorithms; Least squares approximation; Phase change materials; Very large scale integration;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1988. ICASSP-88., 1988 International Conference on
Conference_Location :
New York, NY
DOI :
10.1109/ICASSP.1988.196884
