Implementation of a 4.8 kbps voice codec based on pitch-synchronous DFT coding

Abstract

AB ST RACTThis paper describes a 4.8kbps voice codec based on a coding algorithm using pitch-synchronous DFT [l].This algorithm combines waveform repetition with pitch-synchronous DFT spectral coding in which the phase information and nonharmonic spectral components are ignored. This implementation introduces adaptive post spectral emphasis for the enhancement of the reproduced speech quality.The prototype codec uses three Fujitsu MB86232 digital signal processor (DSP) chips.The reproduced speech signal quality was evaluated and the performance of adaptive post spectral emphasis was compared with that of a d a p t i v e postfiltering [Z].