Performance comparison of 32 Kbps ADPCM coders in noise-free and noisy environments

In this paper a comparative study of several schemes for Adaptive Differential Pulse Code Modulation (ADPCM) with backward adaptation is presented. The work here reported shows a tradeoff between a good signal-to-noise ratio and a low degradation of the receiving quality owing to transmission errors in noisy channels. On this second point, the CCITT standard exhibits a superior behavior to the rest of the schemes, whereas its signal-to-noise ratio will result in 2 or 3 dB less than all the schemes if transmission errors are not considered. In addition, a superior perfomance (around 2 dB) of encoders using lattice predictors with respect to those using transversal predictors is also shown.Peer Reviewe