CWT-Based Approach for Epoch Extraction From Telephone Quality Speech

Epochs are the instants of significant excitation to vocal tract system. Existing methods can extract epochs accurately from clean speech signals. However, identification of epoch locations from band-limited telephonic speech is challenging due to the attenuation of fundamental frequency component and degradation caused by channel effect. This letter proposes an epoch extraction method that can accurately extract epochs from clean as well as telephonic speech signals. In the proposed method, the significant impulse-like discontinuities are extracted directly from the speech signal using continuous wavelet transform. The performance of the proposed method is evaluated using three speakers, namely, SLT, BDL, and JMK from CMU Arctic database. The clean speech is simulated using G.191 software tools to obtain telephonic speech. Experimental results show that the epoch identification rate of proposed method is significantly better than the state-of-the-art methods for the telephone quality speech.