Adaptive postfilter in 16 kbps LD-CELP speech coder

摘要

In September 1992, the recommendation G.728, which a 16 kbps LD-CELP speech coder submitted by AT&T was standardized by CCITT. In the process of ratification test, the coder's performance was equivalent to or better than that of 32 kbps ADPCM for all conditions tested. This paper, which is based on a G.728 encoding-decoding system simulated in software, studies and tests different parts of the algorithm, especially that of the postfilter.