Robust adaptive feedback canceller based on modified pseudo affine projection algorithm

This paper presents an adaptive feedback cancellation (AFC) algorithm with robust and stable performance. The proposed algorithm is based on the pseudo affine projection (PAP) algorithm which approximates the affine projection (AP) with a complexity comparable to the NLMS. Direct application of the PAP to AFC, however, often exhibits instability because of the delayed estimate of the linear prediction (LP) coefficients. This problem is solved in the proposed algorithm by utilizing an inverse gain filter (IGF) before the update of adaptive filter and by estimating the LP coefficients from the input signal without delay. Simulation results confirmed robustness and stability of the proposed algorithm.