Calculation of LPC-based cepstrum coefficients using mel-scale frequency warping

This paper describes a method for warping the frequency axis of cepstrum coefficients in a way analogous to the preprocessing performed by the human ear. The equations are derived and historical background relating to different warping scales is discussed. The calculation is a two-step procedure in which the bilinear transform is used to represent the LPC coefficients on a warped frequency scale. A warping constant determines the degree of transformation. This results in an ARMA representation of the filter transfer function. The second step determines recursively the cepstrum coefficients corresponding to this ARMA transfer function.<
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