LPC parameter vector quantization apparatus, speech coder and speech signal reception apparatus

摘要

In the present invention, there is disclosed an LPC parameter vector quantization apparatus comprising: a first calculation section (102) that calculates distortion (dim) between a plurality of codevectors (LSFim)[i]) read successively from a codebook (101) storing many codevectors (LSFim)[i]) and a quantization target (LSFiT)[i]) using a first distortion evaluation measure; a pre-selection section (103) that preliminarily selects codevectors (LSFiNcand[j][i]), that reduce the amount of distortion (dim) from said plurality of codevectors (LSFim)[i]) according to said first distortion evaluation measure; a second calculation section (108) that calculates distortion (Dij) between the preliminarily selected codevectors (CEPiNcand[j][i]) and said quantization target (LSFiT)[i]) using a second distortion evaluation measure, which is different from said first distortion evaluation measure; and a final search section that specifies a codevector (Nicand[J]), that minimizes the amount of distortion (Dij) according to said second distortion evaluation measure from the preliminarily selected codevectors (CEPiNcand[j][i]) and outputs index information (J) of the specified codevector (Nicand[J]). Disclosed are also a speech coder comprising the above-described LPC parameter vector quantization apparatus and a speech signal reception apparatus provided with a speech coder comprising the LPC parameter vector quantization apparatus according to the present invention.