US 5,781,461 A · Digital signal processing system and method for generating musical legato using multitap delay line with crossfader

Abstract

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.

Claims18

Dependent claims

A sampled data, delay line structure, comprising:

a sampled data delay line having a multiplicity of integer positions at which data is stored;
two readers, each for reading data at a corresponding position of the delay line and generating a corresponding output;
a crossfader that smoothly crossfades between the outputs of the two readers so as to generate an output signal that corresponds to a delay line position that transitions from a first delay line position to a second delay line position;
the output signal produced by the crossfader representing a legato transition between a first musical note corresponding to the first delay line position and a second musical note corresponding to the second delay line position;
and
a controller that assigns to each reader a respective delay line position and that controls when the delay line position read by each reader is updated and also controls when the crossfader begins crossfading from the output of one of said readers to the other of said readers.

3 more elements

A signal processing system, comprising:

a data processor;
and
memory coupled to said data processor for storing data structures and instructions to be executed by said data processor;
said data structures stored in said memory including a sampled data delay line having a multiplicity of integer positions at which data is stored;
said instructions stored in said memory including:
data reading instructions for reading data at a first and second read positions of the delay line associated with first and second read pointers to generate first and second musical note signals;
crossfade instructions that generate an output signal that smoothly crossfades between the first and second musical note signals so as to generate a legato transition therebetween;
and
control instructions that control when the first and second read pointers are each updated and when said crossfade instructions are executed.

6 more elements

Dependencies are inferred from the claim text.

Digital signal processing system and method for generating musical legato using multitap delay line with crossfader

Life of this patent

Digital signal processing system and method for generating musical legato using multitap delay line with crossfader

Life of this patent

Abstract

Claims18