An ATM speech codec with improved reconstruction of lost cells

A speech codec for ATM networks is presented which includes ATM adaptation layer functions, a voice activity detection, and a new method for the reconstruction of lost cells. As the cell assembly already requires a relatively high buffering delay, only algorithms are applied which introduce small additional delays. The reconstruction of lost cells is based on an analysis of the LPC and pitch parameters of the speech signal. The new waveform substitution method considerably reduces the speech quality impairment caused by cell loss.