A compensated-Kalman speech parameter estimator

This paper derives a new form of discrete Kalman estimator for speech parameter estimation. It is developed by considering the parameters themselves to be a process, in a manner similar to that of Lee and Athans. In principle, the algorithm is a two-tiered estimation procedure, implemented via an augmented parameter vector. However, the effective dimensionality of the estimator, and hence the transmission bit-rate, is not changed since the augmentation vector is not transmitted. Improved tracking of speech formants is achieved. Furthermore, this tracking ability is maintained even at very low levels of the speech signal, allowing better estimation during the latter stages of the closed glottis interval. Experimental results are presented for a synthetic "diphthong" with linearly time-varying formants, and a segment of real speech.