This study is to cancel the acoustic feedback signals by using an improved orthogonal projection method in the digital hearing aids. Comparing with the NLMS (normalized least mean square) algorithm with the simplicity and the stability, it gives that the proposed method has the better convergence performances for high correlative signals, and has low computational complexities. We simulated with various input signals to verify the convergence characteristics of this algorithm. And we compared the simulation results by this algorithm with the ones by the NLMS algorithm. Therefore, these works prove that the proposed AOP (advanced orthogonal projection) algorithm shows about 3.1dB higher SNR than the NLMS algorithm for the colored signals in the feedback canceller.

hearing aids, feedback canceller, orthogonal projection, NLMS.