METHOD FOR ADAPTATION OF NOISE MASKING LEVEL TO SYNTHETIC ANALYTICAL VOICE CODER USING SHORT-TERM PERCEPTION WEIGHTINGFILTER

摘要

PROBLEM TO BE SOLVED: To apply a noise masking level to a composed analytical voice coder using a short-period perception weighting filter. SOLUTION: In a composed analytical voice coder using a short-period perception weighting filter having a transmission function of W(z)=A(z/γ1 )/A(z/γ2 ), spectrum extension coefficientsγ1 andγ2 are dynamically applied on the basis of a spectral parameter obtained in short-period linear predicting analysis. The spectral parameter useful for this application may include, particularly, a parameter showing all inclinations of the spectrum of a voice signal and a parameter showing the resonance characteristic of a short-period composing filter 16.