Method and apparatus for encoding speech

摘要

In a speech encoder a Fourier transform of the speech is provided. The Fourier transform is equalized by normalizing the spectrum coefficients to a curve which approximates the shape of the spectrum. Both the curve and the equalized spectrum are encoded. Preferably, only a baseband of the normalized spectrum is encoded and that baseband is repeated in the decoder. The spectrum is normalized by scaling different regions (subbands) of the spectrum differently to flatten the spectrum.