Analysis by synthesis speech coding with generalized pitch prediction

A new analysis-by-synthesis speech coding structure is presented for high-quality speech coding in the 4 to 8 kb/s range. CELP with generalized pitch prediction (GPP-CELP) di ers from classical code-excited linear prediction (CELP) in that for voiced segments it is the speech signal that is decomposed into a component predictable with the aid of the adaptive codebook (ACB) and a nonpredictable aperiodic component, not the LPC residual. The spectrum of the aperiodic component is estimated by linear-prediction analysis. An approximation to the aperiodic component is synthesized from a stochastic codebook of sparse pulse sequences and its spectrum is shaped by the LPC synthesis lter. The ACB contains samples of the past reconstructed signal, low-passed to increase the pitch prediction gain. For voiced segments the new structure yields higher pitch prediction gain and lower linearprediction gain than classical CELP. Subjective and objective comparisons reveal signi cant advantages for GPP-CELP over classical CELP.