The design of a 16 kb/s split-band adaptive predictive coder for noisy channels

This paper describes the design of a high quality 16 Kb/s speech processing scheme known as the Split-Band Adaptive Predictive Coding (SBAPC). In this algorithm, the frequency contents of the input signal are evenly split into two subbands via quadrature mirror filters. Then, adaptive predictive coding (APC) is applied to the subband waveforms. A bit allocation scheme that dynamically alters the quantizer bit assignments according to the energies of the two bands is employed in order to improve further the speech quality. Incorporating forward error correcting codes and noise suppression procedures, the quality of the SBAPC processed speech has been maintained for high background noise levels and channel error rates.