AN IMPROVED RESIDUAL-DOMAIN PHASE/AMPLITUDE MODEL FOR SINUSOIDAL CODING OF SPEECH AT VERY LOW BIT RATES: A VARIABLE RATE SCHEME

An improved harmonic sinusoidal model is presented, where the underlying sine wave amplitudes and phases are eciently represented using a combination of linear predic-tion, linear phase alignment, all-pass ltering, and spectral sampling in the residual-domain. The analysis and synthe-sis systems are introduced and the derivation and encoding of each model parameter is discussed. Performance analy-sis on a large database indicates eective modeling of the sinusoidal parameters. A variable-rate sinusoidal coder op-erating at an average bit rate of 1.75 kbps, based on the proposed model, has been developed, yielding reproduced speech of good quality, intelligibility, and naturalness. The proposed model may nd applications in low bit rate speech coding in high capacity wireless communication systems. 1