Acoustic detection of note bending in stringed M.I.D.I. compatible musical instruments

Claim 2

A pick-up system for a fretted string instrument comprising: transmitter means for propagating an ultrasonic test signal of given frequency along each of a plurality of strings; detector means for detecting an ultrasonic echo signal returned along each of said strings by reflection of said test signal at a point of each of said strings held against a fret and for deriving a peak signal related to said echo signal; first circuit means connected to said transmitter means and said detector means for deriving a first time interval output measured between said propagation and said peak signal indicative of the musical note obtainable by playing each of said strings; and second circuit means operatively associated with said first circuit means for deriving a second time interval output based on a comparison of said first time interval output and a fret reference value and indicative of the degree of string bending by a player.

Claim 3

The system of claim 1 wherein said test signal has a frequency of approximately 40 kilohertz.

Claim 4

The system of claim 1 wherein said second output is related to phase shifting of said peak signal induced by string bending.

Claim 5

The system of claim 1 further comprising processor means connected for converting said first and second outputs to a MIDI compatible system output containing pitch and string bend information for each said string.

Claim 6

The system of claim 1 further comprising third circuit means operatively connected to said detector means and responsive to acoustic vibration of said string in the audible frequency range for deriving a third output indicative of the amplitude of a musical not played on said string.

Claim 7

A M.I.D.I. interfaceable guitar comprising: a guitar having a guitar body, a neck connected at one end to said body and including a head at an opposite end, a string bridge mounted to said body, a plurality of strings stretched between said bridge and said head, and a plurality of frets spaced along said neck; transmitter means for propagating an ultrasonic test signal from a bridge end along each of said strings; detector means for detecting an ultrasonic echo signal returned to said bridge end of each said string by reflection of said test signal at a point of each said string clamped against a fret selected by a player and for deriving a peak signal related to said echo signal; first circuit means connected to said transmitter means and said detector means for deriving a first time interval output indicative of the length of each said string between said bridge and said point and thus indicative of the musical note obtainable by a player touching each said string; and second circuit means associated with said first circuit means for deriving a second time interval output measured between a reference value and said first time interval output and indicative of the degree of bending of each said string by the player.

Claim 8

A M.I.D.I. interfaceable guitar comprising: a guitar having a guitar body, a neck connected at one end to said body and including a head at an opposite end, a string bridge mounted to said body, a plurality of strings stretched between said bridge and said head, and a plurality of frets spaced along said neck; transmitter means for propagating an ultrasonic test signal from a bridge end along each of said strings; detector means for detecting an ultrasonic echo signal returned to said bridge end of each said string by reflection of said test signal at a point of each said string clamped against a fret selected by a player and for deriving a peak signal related to said echo signal; first circuit means connected to said transmitter means and said detector means for deriving a first time interval output indicative of the length of each said string between said bridge and said point and thus indicative of the musical note obtainable by a player touching each said string; and second circuit means associated with said first circuit means for deriving a second time interval output measured between a reference value and said first time interval output and indicative of the degree of bending of each said string by the player.

Claim 9

The guitar of claim 6 wherein said transmitter means and said detector means comprise a plurality of piezoelectric transducers, each of said strings being coupled to a single one of said transducers.

Claim 12

The system of claim 8 wherein said test signal is an ultrasonic acoustic signal.

Claim 13

The method of claim 8 further comprising the steps of sensing acoustic vibration of said string at audible frequencies for deriving a third output indicative of the amplitude of a musical note played on said string.

Claim 14

The method of claim 10 further comprising the step of encoding said first, second and third outputs in standard M.I.D.I. compatible serial digital format.

Claim 15

A string bend pick-up system for a fretted string instrument comprising: transmitter means for propagating a test signal of given frequency along each of a plurality of string; detector means for detecting an echo signal returned along each said string by reflection of said test signal at a point of the string held against a fret; and circuit means for measuring a time interval between propagation of said test signal and detection of said echo signal, comparing said time interval against a stored table of reference values to identify the fret at which said reflection occurred and for deriving an output related to the difference between said time interval and a reference value associated with the identified fret indicative of the degree of string bending by a player.

Claim 16

A string bend pick-up system for a fretted string instrument comprising: transmitter means for propagating a test signal of given frequency along each of a plurality of string; detector means for detecting an echo signal returned along each said string by reflection of said test signal at a point of the string held against a fret; and circuit means for measuring a time interval between propagation of said test signal and detection of said echo signal, comparing said time interval against a stored table of reference values to identify the fret at which said reflection occurred and for deriving an output related to the difference between said time interval and a reference value associated with the identified fret indicative of the degree of string bending by a player.

Claim 17

The system of claim 12 wherein said test signal is an acoustically propagated ultrasonic signal.

Claim 18

The system of claim 12 further comprising second circuit means responsive to an interval between said test signal and said echo signal and deriving a second output indicative of said fret.

Claim 19

The system of claim 12 further comprising third circuit means responsive to acoustic vibration of each said string in the audible frequency range for deriving a third output indicative of the amplitude of a musical note played on said string.