Implementation of VSELP Vocoder of Various Bit Rate

Vector sum excited linear predictive speech coding was studied and enhanced.Presented were the algorithm design and implementation of the VSELP coding at 8kbit/s,and those enhanced at 6.4kbit/s,4.8kbit/s and 2.4kbit/s via vector quantization of LPC parameter,reduction of excitation codebooks and sub block splitting etc.The informal listening showed,that the reconstructed quality of speech (QOS) at 4.8kbit/s and above were not obviously worse than that at 8kbit/s,and of good naturalness intelligibility,but the QOS at 2.4kbit/s was perceivably worse than that at 8kbit/s.