Smoothing the evolution of the spectral parameters in linear prediction of speech using target matching

Linear prediction (LP) coe cients are used to describe the formant structure of a speech waveform. Many factors contribute to the frame-to-frame uctuation of these parameters. These variations adversely a ect the performance of the LP quantizer and the quality of the synthesized speech. For voiced speech, e cient coding of the pitch pulses at the output of the inverse formant lter relies on the similarity of successive pitch waveforms. The performance of this coding stage is also jeopardized by LP variations. In this paper, we propose a new method which smoothes the evolution of the LP parameters. Our algorithm is based on matching the output of the formant predictor to a target signal constructed using smoothed pitch pulses. With this approach we have successfully reduced the frameto-frame variation of LP coe cients, while increasing the similarity of pitch pulses.