Patent ID: 6334105
Filing Date: 2001-12-25
Classification: G10L

Abstract:
A multimode speech coding apparatus comprising:first coding means for coding an LSP parameter indicative of vocal tract information contained in a speech signal;second coding means for coding at least one type of parameter indicative of vocal tract information contained in the speech signal with a plurality of modes;dynamic characteristic extracting means for extracting a dynamic characteristic of a quantized LSP parameter coded in said first coding means, said quantized LSP parameter being indicative of a spectral characteristic of a speech;mode switching means for switching a coding mode of said second coding means based on said dynamic characteristic; andsynthesis means for synthesizing an input speech signal incorporating and using a plurality of types of parameter information coded in said first coding means and said second coding means,wherein said second coding means comprises coding means for coding an excitation vector with a plurality of coding modes, said mode switching means switches said coding mode of said second coding means using said quantized LSP parameter indicative of a spectral characteristic of a speech, whereby information concerning said coding mode is not explicitly included in the synthesized input speech signal.