Apparatus for compressing a digital input signal with signal spectrum-dependent and noise spectrum-dependent quantizing bit allocation

摘要

PURPOSE: To obtain a characteristic desirable for an auditory sense, and satisfactory in the input of an isolated spectrum, by one arithmetic operation without repeatedly adjusting bit amounts many times. ;CONSTITUTION: At the time of adaptively operating the bit assignment of spectrum data orthogonally transformed and supplied from an input terminal 301 by each critical band, entire bits usable for the bit assignment are divided into the assignment amounts at a bit distributing circuit 304 depending on the energy of a signal, and the assignment amounts at a bit distributing circuit 305 depending on an auditory sense permitting noise spectrum, and distributed. Then, a division rate at that time is decided by a bit division rate deciding circuit 309 according to an output from a spectrum smoothness calculating circuit 308.;COPYRIGHT: (C)1994,JPO&Japio