| 摘要 |
PURPOSE:To improve the coding efficiency of a filter by making filter length a parameter from a viewpoint of data compression, and making coding gain maximum. CONSTITUTION:The filter length is made the parameter, and the coding gain is made a constant represented by a formula 1. In this case, K is the number of bands to be band-split, AK is the constant to be determined from a filter factor hK(n) and the coefficient of correlation of an input signal, BK is the constant to be determined from the filter factor g'K(n) and the coefficient of correlation of a quantization error, and LK is the constant to be determined from the sampling rate of a K-th band. Accordingly, an input signal X(n) is divided into two bands by digital filters 2, 3. These signals having passed through the digital filters 2, 3 are sampled at the half of Nyquist frequency by sampling circuits 10, 11, and are coded by a coding circuit. |
