VECTOR QUANTISATION DEVICE AND VECTOR QUANTISATION METHOD

摘要

Disclosed is a vector quantisation device which can reduce the computational complexity of an audio codec without reducing the audio quality. A vector quantisation device (112) searches a codebook using code vectors, with which the impulse response of an audibility weighted synthesis filter is convolved and which configure the codebook, and target vectors. A filtering unit (201) applies a filter exhibiting a low pass and/or a high pass characteristic to the impulse response. If the filter has a high pass characteristic, a compaction unit (202) then compacts the degree of the post-filtering impulse response. A convolution unit (203) convolves the post-filtering impulse response with each of the code vectors. If the filter has a low pass characteristic, a search unit (204) thins out elements of the plurality of code vectors with which the impulse response has been convolved, and elements of the target vectors.