Quality comparison of low complexity 4800 bps self excited and code excited vocoders

This paper presents a formal objective and subjective comparison of a number of LPC vocoders which operate at bit rates around 4800 bps. In this work, particular emphasis is placed on the Self Excited Vocoder (SEV), a new speech coding approach which was introduced by the authors at ICASSP86 [1]. Many members of a class of LPC vocoders of which the SEV, the well known Multiple Pulse Excited Linear Predictive Coder (MPLPC) [2], and Code Excited Linear Predictive Coder (CELPC) [3] are members, are simulated and compared. Through these experiments, the SEV is shown to be a low complexity, simply implemented speech coder that is competitive with the other coders in this class in producing high quality speech at low bit rates.