Low bit rate coding manner of digital voice data and decoding device of digital voice data

摘要

PURPOSE: To attain the coding of data with high resolution by dividing input digital data into plural bands so that the band width is gradually expanded in the high frequency region and forming a block consisting of plural samples in each band and executing orthogonal transformation in each block to obtain coefficient data. CONSTITUTION: The coding device is constituted of a filler bank 4, orthogonal transformation circuits 51 to 55 for executing orthogonal transformation such as fast Fourier transformation and an allocating bit number determining circuit 6 for determining the number of allocating bits in each frequency band. Input digital data are divided into plural (n) bands so that the band width is gradually expanded toward the high frequency region and orthogonal transformation is executed in each block of each band to obtain coefficient data. Consequently and high frequency resolution can be obtained in the low frequency band and high time resolution can be obtained in the high frequency band in which a steady state is short.