METHOD AND APPARATUS FOR BANDWIDTH EXTENSION ENCODING AND DECODING

摘要

A band-width extension encoding and decoding method and an apparatus thereof are provided to prevent the lowering of the speech quality in spite of the use of the small amount of bits in the encoding and decoding processes. An excited signal extraction member(105) removes an envelope line at the lower frequency signal corresponding to the area smaller than that of the predetermined frequency, extracts the excited signal, and converts the domain of the extracted excited signal into the frequency domain. A spectrum producing member(115) produces a spectrum to be arranged at the area larger than that of the predetermined frequency by means of spectrum of the converted excited signal. The produced spectrum and the spectrum of the high frequency signal are compared by a gain value calculating member. The gain value calculating member(125) calculates the gain value.