Spectrum coding apparatus, spectrum decoding apparatus, acoustic signal transmission apparatus, acoustic signal reception apparatus and methods thereof

摘要

A spectrum coding apparatus capable of performing coding at a low bit rate and with high quality is disclosed. This apparatus is provided with a section that performs the frequency transformation of a first signal and calculates a first spectrum, a section that converts the frequency of a second signal and calculates a second spectrum, a section that estimates the shape of the second spectrum in a band of FL<=k<FH using a filter having the first spectrum in a band of 0<=k<FL as an internal state and a section that codes an outline of the second spectrum determined based on a coefficient indicating the characteristic of the filter at this time.