Chapter_09_part-1 语音信号的线性预测分析1.pdf

Chapter 9 Linear Predictive Analysis of Speech Signals 语音信号的线性预测分析 1 LPC Methods • LPC methods are the most widely used in speech coding, speech synthesis, speech recognition, speaker recognition and verification and for speech storage – LPC methods provide extremely accurate estimates of speech parameters, and does it extremely efficiently – basic idea of Linear Prediction: current speech sample can be closely approximated as a linear combination of past samples, i.e., 2 LPC Methods • for periodic signals with Np period , it is obvious that but that is not what LP is doing; it is estimating s(n) from the p (p Np ) most recent values of s(n) by linearly predicting its value • for LP, the predictor coefficients (the αs) are determined k (computed) by minimizing the sum of squared differences (over a finite interval) between the actual speech samples and the linearly predicted ones 3 Speech Production Model • the time-varying digital filter represents the effects of the glottal pulse shape, the vocal tract IR, and radiation at the lips • the system is excited by an impulse train for voiced speech, or a random noise sequence for unvoiced speech