| 摘要 |
A sampled data, delay line structure that includes a sampled data delay line, two readers for reading data at corresponding positions of the delay line, controller that controls when the read position of each reader is updated for a new note of a different pitch, and a crossfader that crossfades between the outputs of the two readers to produce a legato transition between the two discrete notes associated with the two readers. The controller receives a control signal indicating a sequence of note events to be implemented by the delay line structure. When a new note on event occurs while a previous note is still playing, a legato crossfade sequence is performed. In particular, the delay line reader not used by the previous note is set to a delay position associated with the new note, and the crossfader is enabled. The crossfader gradually transitions its output from that of the reader used for the previous note to the output of the reader used from the new note. Each reader may include an interpolation filter, such as an allpass filter, so that the delay line length associated with each note can be a non-integer value. The crossfade ramp used by the crossfader is preferably an "s-shaped" non-linear function.
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