| 摘要 |
This invention is concerned with pitch shift apparatus for converting an audio signal into PCM digital data and then making a pitch shift, wherein the PCM digital data is written in a ring memory (2) by a write address generator circuit (3), and read therefrom by two read address generator circuits (4, 5) which start to read at time points differing by an amount corresponding to 1/2 the ring memory (2) at a certain pitch, in which case immediately before the read address on the now finally outputting side and the write address causes passing or cyclic delay, the read address on the switching-to side is stopped from increasing during the interval from a time point at which an audio signal on the switching-to side makes zero crossing to a time at which an audio signal on the now outputting side makes in-phase zero crossing, and switching is made at the zero crossing point, so that the connection of the audio signals can be smoothly made without such AM modulated component as caused in the cross fade method, enabling high-quality pitch shift to be achieved. |
