Efficient algorithm for multi-pulse LPC analysis of speech

The introduction of multi-pulse excitation for LPC coders has increased the quality achievable for digitally coded speech at bit rates in the 9.6 Kbs range. A simplified multi-pulse analysis is proposed here with particular emphasis on the speech model developed as a result of a two-pass method. In the first pass, estimated LPC parameters generated by conventional covariance analysis are used to generate the forward prediction error; the multi-pulse sequence is then detected by thresholding the residual. The second pass generates the final LPC parameters by a covariance analysis incorporating knowledge of the estimated pulse locations and amplitudes along with perceptual synthesis error weighting. Experimental results are presented to demonstrate the method.