The G.729 And Amr The Cascade Voice Intelligibility Improve The Technical Studies

With the rapid development of wireless communication technology, interoperability between various communication networks becomes increasingly important.So the cascade work between kinds of speech codecs can't be inevitable, such as the widely used G.729 and AMR codecs in mobile communications.However the cascade work brings distinct decline in speech intelligibility.Therefore, the purpose of the paper is finding a way to provide a low-cost speech intelligibility enhancement solution without changing the existing network equipments. Based on the detailed analysis of the reason why the cascade work of G.729 and AMR lead to the decline in speech intelligibility and combining the existing high-frequency compensation methods, the dissertation provides a speech intelligibility enhancement solution based on the hanning window function. According to the MATLAB simulation,the method shows certain effect on speech intelligibility enhancement.The main work of the dissertation is organized as below:1. Introducing the the basic properties and processing methods of speech signal;2. Giving a feasible solution on the reason why the cascade work of G.729 and AMR lead to the decline in speech intelligibility according to detailed analysis;3. Detailed introducing the speech intelligibility solution,including the decision of voiced/unvoiced segments, high-frequency compensation of voiced speech and formant enhancement ;4. MATLAB simulating and algorithm evaluation.