An Efficient Linear-Prediction Vocoder

A primary interest in any method for producing synthetic speech is to minimize the number of bits per second required to generate acceptable quality speech. An efficient method for transmitting the linear-prediction parameters has been found by using the techniques of differential PCM. Using this technique, speech transmission is achieved employing fewer than 1500 bits/s. Further reductions in the linear-prediction storage requirements can be realized at a cost of higher system complexity by transmission of the most significant eigenvectors of the parameters. This technique in combination with differential PCM can lower the storage to 1000 bits/s.