A 4800 bps voice excited predictive coder (VEPC) based on improved baseband/Sub-bands filters

A Voice Excited Predictive Coding architecture (VEPC) has been recently proposed allowing to compress digital speech at bit rates of 9600/7200 bps with a telephone quality. In order to decrease the bit rate down to 4800 bps, while preserving a same level of quality, several improvements of the processing blocks have been considered: · an adaptive pre-emphasis of the predictor coefficients, · a five to one decimation of the residual signal to reduce the residual baseband to 800 Hz, · a parallel implementation of the sub-bands splitting-reconstruction. This paper deals with the improvements as well as the implementation aspects. Taped results will be played at the conference.