Patent ID: 8924208

Claim:
A speech coding method comprising: performing a modified discrete cosine transformation for an input speech signal to provide spectrum data; performing algebraic vector quantization coding using the spectrum data at a bit rate of 4 kbit/s or 12 kbit/s, the algebraic vector quantization coding comprising: calculating a global gain for the spectrum data; dividing the spectrum data into a plurality of subbands; correcting the spectrum data of each subband of the plurality of subbands; transforming the corrected spectrum data into a lattice vector; calculating index information from the lattice vector; and multiplexing the global am with the index information to generate coded information, and outputting the coded information, which is related to the speech signal to be transmitted to a speech decoding apparatus, wherein the correcting calculates an average value of an amplitude of spectrum data for each subband, and assigns zero to a value of a sample having an amplitude equal to or less than the average value, among the group of samples related to the spectrum data of each subband, wherein at least one of the performing modified discrete cosine transformation, performing algebraic vector quantization coding, calculating a global gain, dividing, correcting, transforming, calculating index information and multiplexing is performed by a processor.