Vector quantization in a harmonic speech coding arrangement
AssigneeAT&T Bell Laboratories
InventorDavid L. Thomson
Life of this patent
Estimating the term…
Abstract
A harmonic speech coding arrangement where vector quantization is used to improve speech quality. Parameters are determined at the analyzer of an illustrative coding arrangement to model the magnitude and phase spectra of the input speech. A first codebook of vectors is searched for a vector that closely approximates the difference between the true and estimated magnitude spectra. A second codebook of vectors is searched for a vector that closely approximates the difference between the true and the estimated phase spectra. Indices and scaling factors for the vectors are communicated to the synthesizer such that scaled vectors can be added into the magnitude and phase spectra for use at the synthesizer in generating speech as a sum of sinusoids.
Claims20
In a harmonic speech coding arrangement, a method of processing speech comprising
- determining a spectrum comprising a Fourier transform of said speech,
- calculating, based on said determined spectrum, a set of parameters modeling said speech, at least one parameter of said parameter set comprising an index to a codebook of vectors,
- communicating said calculated parameter set including said index,
- receiving said communicated parameter set including said index,
- processing said received parameter set including said index to determine a plurality of sinusoids corresponding to harmonics of said speech, and
- synthesizing speech as a sum of said sinusoids.
In a harmonic speech coding arrangement, a method of processing speech comprising
- determining a spectrum from said speech,
- calculating, based on said determined spectrum, a set of parameters modeling said speech and
- communicating said parameter set, wherein at least one parameter of said parameter set comprises an index to a codebook of vectors, and
- wherein said determining comprises determining a magnitude spectrum and a phase spectrum, and wherein said calculating comprises
- calculating said parameter set comprising first parameters modeling said determined magnitude spectrum and second parameters modeling said determined phase spectrum, at least one of said first parameters comprising an index to a first codebook of vectors, and at least one of said second parameters comprising an index to a second codebook of vectors.
In a harmonic speech coding arrangement, a method of processing speech comprising
- determining a spectrum from said speech,
- calculating, based on said determined spectrum, a set of parameters modeling said speech and
- communicating said parameter set, wherein at least one parameter of said parameter set comprises an index to a codebook of vectors, and
- wherein said calculating comprises
- determining a plurality of sinusoids from said determined spectrum, including determining sinusoidal amplitude of each of said plurality of sinusoids,
- estimating, based on said speech, sinusoidal amplitude of each of said plurality of sinusoids,
- determining errors between said determined sinusoidal amplitudes and said estimated sinusoidal amplitudes, and
- vector quantizing said determined errors to determine said index.
In a harmonic speech coding arrangement, a method of processing speech comprising
- determining a spectrum from said speech,
- calculating, based on said determined spectrum, a set of parameters modeling said speech and
- communicating said parameter set, wherein at least one parameter of said parameter set comprises an index to a codebook of vectors, and
- wherein said calculating comprises
- determining a plurality of sinusoids from said determined spectrum, including determining sinusoidal frequency of each of said plurality of sinusoids,
- estimating, based on said speech, sinusoidal frequency of each of said plurality of sinusoids,
- determining errors between said determined sinusoidal frequencies and said estimated sinusoidal frequencies, and
- vector quantizing said determined errors to determine said index.
In a harmonic speech coding arrangement, a method of processing speech comprising
- determining a spectrum from said speech,
- calculating, based on said determined spectrum, a set of parameters modeling said speech and
- communicating said parameter set, wherein at least one parameter of said parameter set comprises an index to a codebook of vectors, and
- wherein said calculating comprises
- determining a plurality of sinusoids from said determined spectrum, including determining sinusoidal phase of each of said plurality of sinusoids,
- estimating, based on said speech, sinusoidal phase of each of said sinusoids,
- determining errors between said determined sinusoidal phases and said estimated sinusoidal phases, and
- vector quantizing said determined errors to determine said index.
A harmonic coding arrangement for processing speech comprising
- means responsive to said speech for determining a spectrum comprising a Fourier transform of said speech,
- means responsive to said determining means for calculating, based on said determined spectrum, a set of parameters modeling said speech, at least one parameter of said parameter set comprising an index to a codebook of vectors,
- means for communicating said calculated parameter set including said index,
- means for receiving said communicated parameter set including said index,
- means for processing said received parameter set including said index to determine a plurality of sinusoids corresponding to harmonics of said speech, and
- means for synthesizing speech as a sum of said sinusoids.
Dependencies are inferred from the claim text.