Design of Normalized Subband Adaptive Filter for Acoustic Echo Cancellation

In hands-free telephones and teleconferencing systems, acoustic echo cancellers are required, which are often implemented by adaptive filters. In these applications, the speech input signal of the adaptive filter is highly correlated and the impulse response of the echo path is very long. These characteristics will slow down the convergence rate of the adaptive filter if the well-known normalized leastmeansquare (NLMS) algorithm is used. The normalized subband adaptive filter (NSAF) offers a good solution to this problem because of its decorrelating property. This paper proposes a VHDL implementation of normalized subband adaptive filter structure(NSAF) adaptive algorithm.the experiment result shows that the power consumed by subband is lower than that of full band. Index Terms — Acoustic echo canceller, adaptive combination, normalized subband adaptive filter (NSAF), hands-free telephone, teleconferencing system Cascade intergrator-comb filter (CIC).