Patent ID: 7680669
Filing Date: 2010-03-16
Classification: G10L,H03M

Abstract:
1. A sound encoding apparatus having spectral parameter calculating means for receiving a sound signal and calculating a spectral parameter, spectral parameter quantizing means for quantizing the spectral parameter calculated by said parameter calculating means and outputting the quantized spectral parameter, impulse response calculating means for converting the output spectral parameter from said spectral parameter quantizing means into an impulse response, adaptive code book means for obtaining a delay and gain from a past quantized sound source signal on the basis of an adaptive code book to predict a sound signal and obtain a residual signal, and outputting the delay and gain, a sound source signal of the sound signal being represented by a combination of pulses having non-zero amplitudes, and sound source quantizing means for quantizing the sound source signal and gain of the sound signal by using the impulse response, and outputting the quantized sound source signal and gain, comprising: position code book storing means for storing a plurality of types of position code books, each containing an identical set of pulse positions, each of said types of position code books providing a different association of a plurality of said pulses with a subset of pulse positions within said identical set of pulse positions that is different from associations between said pulses and said subsets of pulse positions in the remaining types of position code books; position code book selecting means for selecting one type of code book from said plurality of types of position code books on the basis of at least one of the delay and gain of said adaptive code book, said sound source quantizing means calculating a distortion of the sound signal by using the impulse pulse response for each of all combinations of positions that a plurality of pulses contained in the thus selected position code book can take respectively, and quantizing a pulse position by selecting a combination of positions at which the distortion is decreased; and multiplexer means for combining an output from said spectral parameter quantizing means, an output from said adaptive code book means, and an output from said sound source quantizing means, and outputting the combination.