Noise reduction system based on frequency domain adaptive filter using modified DFT pair: introduction of pitch detector

摘要

The noise reduction system based on the frequency domain adaptive filter (FDAF) using the modified DFT pair (MDFTP) has the structure of the adaptive line enhancer (ALE). Therefore, stable noise reduction performance is obtained by adjusting the delay element of the ALE according to the pitch of speech. In this paper, we propose to detect the pitch by using the MDFT output. It enables to suppress increase of computational complexity due to cooperate the pitch detector into the noise reduction system Moreover, to improve the noise reduction performance, we propose to damp the normalized step size of the EDAF. The effectiveness of the proposed system is examined through computer simulations in speech signal. As a result, it was confirmed that the proposed system had the ability to improve the signal to noise ratio (SNR) form 13dB to 8dB.