Speech coding below 4 kb/s using waveform interpolation

A new method of coding voiced speech is described. The method transmits a prototype waveform describing a single-pitch cycle at 20-30 ns intervals. The waveform is deconvolved into a prototype excitation waveform and a set of linear prediction (LP) coefficients describing the format structure. At any time during the interpolation interval, a description of the shape of the excitation over one pitch cycle, the instantaneous excitation waveform, can be obtained by linearly interpolating the prototype excitation waveforms. The speech signal is reconstructed by filtering an excitation signal consisting of the concatenation of sections of the instantaneous excitation waveforms