The 1.2 kbps/2.4 kbps MELP speech coding suite with integrated noise pre-processing
John S. Collura, D.F. Brandt, D.J. Rahikka · 2003
Previous advances in speech enhancement and noise pre-processing algorithms have dramatically improved the quality and intelligibility of speech signals, both in the presence of acoustic noise as well as in benign environments. The use of speech enhancement in combination with voice coding algorithms and applied to governmental wireless communications systems is an area of increasing importance. In March 1996, the US government selected the 2.4 kbps MELP speech coding algorithm for applications which require high quality/intelligibility narrow band speech coding. In March of 1999, a companion 1.2 kbps MELP speech coding algorithm was unveiled. This additional MELP rate was added to satisfy disadvantaged transmission requirements such as survivable SATCOMs or high latitude HF radio links. The combined 1.2 kbps/2.4 kbps MELP algorithm incorporates an integrated speech enhancement algorithm as a front-end process to provide superior performance in harsh acoustic noise environments. This paper introduces the integrated speech enhancement 1.2 kbps/2.4 kbps MELP speech coding algorithmic suite, and presents the first available test data for the combined algorithm. Finally, a discussion of the test conditions, results and related issues are presented.