Abstract:
Speech coding is a very important area that finds civilian and military applications. It
can be considered as one of the important stages in speech processing. It is used to
compress speech; this is because the speech signal is very redundant. Speech coding has
many applications; it is used in digital telephony, in multimedia and in security of
digital communications. In this paper, we focused on developing algorithms and
methods for a waveform speech coder operating at low bit rate with good quality
reconstructed speech signal. Moreover, a new model for linear predictive coding of
speech that can be used to produce high quality speech at low data rate is introduced. In
this model, we divided the residual (excitation signal) to subframes and made energy
and voice / unvoice classifications to choose the best pulses in the residual that give us
low bit rate and good quality for the reconstructed speech. Hence, this vocoder forms an
excitation sequence which consists of groups of uniformly spaced pulses. During
analysis the amplitude and LP coefficients of the pulses are determined. In addition, a
new technique in the quantization of the amplitude of each pulse as well as linear
prediction parameters is proposed.