A multipulse excited pole-zero filtering approach for speech enhancement

The use of a pole-zero filter and multipulse excitation is proposed to enhance a noisy voiced speech segment. The excitation signal is regarded as the sum of two components: a unipolar periodic impulse train and a randomly distributed bipolar pulse sequence (usually of much smaller amplitude). The periodic impulse train is extracted to estimate the pole-zero filter without any phase constraint, while the small secondary pulses are added to reduce the reconstruction error as desired. it is shown that this procedure offers an efficient modeling scheme in high SNR conditions and can improve the SNR of 5-dB speech by as much as 5.16 dB