| 摘要 |
A pitch shifter capable of shifting an acoustic signal in pitch to an arbitrary level with a high degree of accuracy without any change in reproduction time, and also sufficiently reducing high-frequency distortion without being increased in size or speeded-up is provided. Stored in a filter coefficient string storage 6, four filter coefficient strings corresponding to four sub-filters produced through polyphase decomposition of a low-pass filter for 4-fold oversampling. Filter coefficient string selectors 5a and 5b select, based on the first and second bits of the decimal part of each of read addresses generated by the read address generators 4a and 4b, respectively, any one of the four filter coefficient strings stored in the filter coefficient string storage 6. Filter operation units 2a and 2b receive paired sound data strings, and carry out a filter operation by using the filter coefficient strings selected by the filter coefficient string selector 5a and 5b, respectively.
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