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US5859378A Expired / Lapsed US ⏱️ 0.0 years remaining

Musical instrument self-tuning system with capo mode

Assignee: Transperformance LLC
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Filing: 1996-07-12
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Granted: 1999-01-12
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Expires: 2016-07-12
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Abstract

Abstract The invention is a control system for automatically tuning a stringed musical instrument with a capo installed, using an original calibration function or closed-loop tuning system for the instrument without the capo. The control system uses a capo scale factor which scales frequencies measured with the capo installed to what they would have been without a capo. The control system enables a musician to quickly tune an instrument after installing a capo, in a manner unlikely to be noticed by an audience.

Inventors

  • 👤 Stephen J. Freeland
  • 👤 Neil C. Skinn

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 14:39
CPC Classifications
G; G10; G10G; G10G7/00; G10G7/02; G10D; G10D3/00; G10D3/053; Y; Y10; Y10S; Y10S84/00; Y10S84/18

Claims Analysis

Total Claims: 56
Claim 1
Independent Claim 125 words
A control system for an automatically tuned fretted stringed instrument adapted for use with a capo installed on one fret, said instrument having a plurality of strings, each string having an actuator connected thereto, said instrument further having a transducer coupled to said strings, said control system comprising: a processor adapted to be coupled to the transducer and to the actuators, said processor including means for receiving a transducer signal from said transducer, means for obtaining the measured frequency of each of said plurality of strings from said transducer signal, means for scaling said measured frequency of each string by a capo scale factor, means for generating control signals in accordance with the scaled frequencies, and means for outputting said control signals to said actuators.
Claim 2
Dependent Claim 125 words
A control system for an automatically tuned fretted stringed instrument adapted for use with a capo installed on one fret, said instrument having a plurality of strings, each string having an actuator connected thereto, said instrument further having a transducer coupled to said strings, said control system comprising: a processor adapted to be coupled to the transducer and to the actuators, said processor including means for receiving a transducer signal from said transducer, means for obtaining the measured frequency of each of said plurality of strings from said transducer signal, means for scaling said measured frequency of each string by a capo scale factor, means for generating control signals in accordance with the scaled frequencies, and means for outputting said control signals to said actuators.
Claim 3
Dependent Claim 45 words
The control system of claim 1 wherein said instrument has twelve frets per octave and wherein said capo scale factor is 2 - (n/12), where n is the number of the fret on which the capo is installed and n=0 if no capo is installed.
Claim 4
Dependent Claim 25 words
The control system of claim 1 adapted for use with a capo sensor, coupled to said processor, wherein said capo sensor senses an installed capo.
Claim 5
Dependent Claim 24 words
The control system of claim 1 wherein said processor detects an installed capo based on the measured string frequency of one of the strings.
Claim 6
Dependent Claim 42 words
The control system of claim 4 wherein said processor determines on which fret, n, a capo is installed based on the relationship: f.sub.meas /f.sub.open =2.sup.(n/12), where f meas and f open are the measured and target open frequencies, respectively, of said string.
Claim 7
Dependent Claim 22 words
The control system of claim 5 wherein said processor determines n based on the measured string frequencies of more than one string.
Claim 8
Dependent Claim 23 words
The control system of claim 1 further including an operator interface coupled to said processor, for receiving operator input from an instrument operator.
Claim 9
Dependent Claim 14 words
The control system of claim 7 wherein said operator input indicates an installed capo.
Claim 10
Dependent Claim 19 words
The control system of claim 8 wherein said operator input further indicates on which fret said capo is installed.
Claim 11
Dependent Claim 17 words
The control system of claim 8 wherein said processor determines on which fret said capo is installed.
Claim 12
Dependent Claim 44 words
The control system of claim 10 wherein said processor determines on which fret, n, said capo is installed based on the relationship: f.sub.meas /f.sub.open =2.sup.(n/12), where f meas and f open are the measured and target open frequencies, respectively, of one of the strings.
Claim 13
Dependent Claim 21 words
The control system of claim 7 wherein said operator interface further comprises means for displaying instrument conditions to said instrument operator.
Claim 14
Dependent Claim 17 words
The control system of claim 1 wherein said means for generating control signals comprises a calibration function.
Claim 15
Dependent Claim 26 words
The control system of claim 13 wherein said calibration function relates the actuator position for a given string to the target open frequency of said string.
Claim 16
Dependent Claim 37 words
The control system of claim 14 wherein said calibration function relates the actuator position for a given string to the target open frequency to the first power and to the target open frequency squared of said string.
Claim 17
Dependent Claim 30 words
The control system of claim 14 wherein said calibration function relates the actuator position for a given string to the target open frequencies of each of said plurality of strings.
Claim 18
Dependent Claim 41 words
The control system of claim 16 wherein said calibration function relates the actuator position for a given string to the target open frequencies to the first power and to the target open frequencies squared of each of said plurality of strings.
Claim 19
Dependent Claim 22 words
The control system of claim 14 wherein said means for generating control signals further includes modifying means for modifying said calibration function.
Claim 20
Dependent Claim 21 words
The control system of claim 18 wherein said calibration function is modified by adding a constant term to said calibration function.
Claim 21
Dependent Claim 34 words
The control system of claim 18 wherein said calibration function is modified by a function of the difference between the scaled frequency of a given string and the target open frequency of said string.
Claim 22
Dependent Claim 44 words
The control system of claim 18 wherein said calibration function is modified by a function of the difference between the actuator position computed for the target open frequency of a given string and the actuator position computed for the scaled frequency of said string.
Claim 23
Dependent Claim 15 words
The control system of claim 21 wherein said difference is subtracted from said calibration function.
Claim 24
Dependent Claim 35 words
The control system of claim 18 wherein said modifying means comprises a closed-loop system for adjusting the actuator position of a given string until the scaled frequency is approximately equal to said target open frequency.
Claim 25
Dependent Claim 28 words
The control system of claim 23 wherein said calibration function is modified by a function of the difference between the new actuator positions and the previous actuator positions.
Claim 26
Dependent Claim 15 words
The control system of claim 18 further including means for storing the modified calibration function.
Claim 27
Dependent Claim 17 words
The control system of claim 13 wherein said processor further comprises means for generating said calibration function.
Claim 28
Dependent Claim 57 words
The control system of claim 26 wherein said means for generating a calibration function comprises means for acquiring f k and x k , the measured frequency and actuator positions, respectively, for a given string at a plurality, k, of actuator positions, and means for generating therefrom a function relating x to f for said given string.
Claim 29
Dependent Claim 64 words
The control system of claim 26 wherein said means for generating a calibration function comprises means for acquiring f jk and x jk the measured frequency and actuator positions, respectively, for j strings, each string at a plurality, k, of actuator positions, and means for generating therefrom a function relating x j for a given actuator j to f j for all j strings.
Claim 30
Dependent Claim 24 words
The control system of claim 13 wherein said calibration function can be used to calculate target actuator positions for a plurality of tuning configurations.
Claim 31
Dependent Claim 17 words
The control system of claim 1 wherein said means for generating control signals comprises a closed-loop system.
Claim 32
Dependent Claim 47 words
The control system of claim 30 wherein said closed-loop system takes the difference between the scaled frequency of a given string and the target open frequency of said string and generates an error signal therefrom, and wherein said control signal is a function of said error signal.
Claim 33
Dependent Claim 116 words
An automatically tuned fretted stringed instrument adapted for use with a capo installed on one fret, comprising: a plurality of strings; a plurality of actuators, one of said actuators connected to each of said strings; a transducer coupled to said strings; and a processor coupled to said transducer and to said actuators, said processor including means for receiving a transducer signal from said transducer, means for obtaining the measured frequency of each of said plurality of strings from said transducer signal, means for scaling said measured frequency of each string by a capo scale factor, means for generating control signals in accordance with the scaled frequencies, and means for outputting said control signals to said actuators.
Claim 34
Dependent Claim 116 words
An automatically tuned fretted stringed instrument adapted for use with a capo installed on one fret, comprising: a plurality of strings; a plurality of actuators, one of said actuators connected to each of said strings; a transducer coupled to said strings; and a processor coupled to said transducer and to said actuators, said processor including means for receiving a transducer signal from said transducer, means for obtaining the measured frequency of each of said plurality of strings from said transducer signal, means for scaling said measured frequency of each string by a capo scale factor, means for generating control signals in accordance with the scaled frequencies, and means for outputting said control signals to said actuators.
Claim 35
Dependent Claim 44 words
The instrument of claim 32 wherein said instrument has twelve frets per octave and wherein said capo scale factor is 2 - (n/12), where n is the number of the fret on which the capo is installed and n=0 if no capo is installed.
Claim 36
Dependent Claim 23 words
The instrument of claim 32 wherein said processor detects an installed capo based on the measured string frequency of one of the strings.
Claim 37
Dependent Claim 41 words
The instrument of claim 34 wherein said processor determines on which fret, n, a capo is installed based on the relationship: f.sub.meas /f.sub.open =2.sup.(n/12), where f meas and f open are the measured and target open frequencies, respectively, of said string.
Claim 38
Dependent Claim 23 words
The instrument of claim 32 further including a n operator interface coupled to said processor, for receiving operator input from an instrument operator.
Claim 39
Dependent Claim 13 words
The instrument of claim 36 wherein said operator input indicates an installed capo.
Claim 40
Dependent Claim 18 words
The instrument of claim 37 wherein said operator input further indicates on which fret said capo is installed.
Claim 41
Dependent Claim 16 words
The instrument of claim 37 wherein said processor determines on which fret said capo is installed.
Claim 42
Dependent Claim 43 words
The instrument of claim 39 wherein said processor determines on which fret, n, said capo is installed based on the relationship: f.sub.meas /f.sub.open =2.sup.(n/12), where f meas and f open are the measured and target open frequencies, respectively, of one of the strings.
Claim 43
Dependent Claim 16 words
The instrument of claim 32 wherein said means for generating control signals utilizes a calibration function.
Claim 44
Dependent Claim 29 words
The instrument of claim 41 wherein said calibration function relates the actuator position for a given string to the target open frequencies of each of said plurality of strings.
Claim 45
Dependent Claim 21 words
The instrument of claim 41 wherein said means for generating control signals further includes modifying means for modifying said calibration function.
Claim 46
Dependent Claim 20 words
The instrument of claim 43 wherein said calibration function is modified by adding a constant term to said calibration function.
Claim 47
Dependent Claim 33 words
The instrument of claim 43 wherein said calibration function is modified by a function of the difference between the scaled frequency of a given string and the target open frequency of said string.
Claim 48
Dependent Claim 43 words
The instrument of claim 43 wherein said calibration function is modified by a function of the difference between the actuator position computed for the target open frequency of a given string and the actuator position computed for the scaled frequency of said string.
Claim 49
Dependent Claim 14 words
The instrument of claim 43 further including means for storing the modified calibration function.
Claim 50
Dependent Claim 16 words
The instrument of claim 41 wherein said processor further comprises means for generating said calibration function.
Claim 51
Dependent Claim 23 words
The instrument of claim 41 wherein said calibration function can be used to calculate target actuator positions for a plurality of tuning configurations.
Claim 52
Independent Claim 105 words
A method for tuning a fretted stringed instrument having an installed capo, said instrument having a plurality of strings, each string having an actuator connected thereto, said instrument further having a transducer coupled to said strings and a processor coupled to said transducer and to said actuators, said method comprising the steps of: installing a capo on one fret; strumming said strings; measuring the frequency of each of said plurality of strings from a transducer signal; scaling the measured frequency of each string by a capo scale factor; generating control signals in accordance with the scaled frequencies; and outputting said control signals to said actuators.
Claim 53
Independent Claim 105 words
A method for tuning a fretted stringed instrument having an installed capo, said instrument having a plurality of strings, each string having an actuator connected thereto, said instrument further having a transducer coupled to said strings and a processor coupled to said transducer and to said actuators, said method comprising the steps of: installing a capo on one fret; strumming said strings; measuring the frequency of each of said plurality of strings from a transducer signal; scaling the measured frequency of each string by a capo scale factor; generating control signals in accordance with the scaled frequencies; and outputting said control signals to said actuators.
Claim 54
Dependent Claim 37 words
The method of claim 50 wherein said instrument has twelve frets per octave and wherein said capo scale factor is 2 - (n/12), where n is the number of the fret on which the capo is installed.
Claim 55
Dependent Claim 27 words
The method of claim 50 further comprising the step of determining on which fret said capo is installed from the measured frequency of one of the strings.
Claim 56
Dependent Claim 94 words
The method of claim 50 wherein said step of generating control signals comprises the steps of: providing a calibration function relating the actuator position for a given string to the target open frequencies of each of said plurality of strings; inserting said scaled frequencies into said calibration function to compute new actuator positions; computing the difference between said new actuator positions and the previous actuator positions, said previous actuator positions computed by inserting said target open frequencies into said calibration function; and modifying said calibration function by adding said difference to said calibration function.

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3.5 Years (Year 4) 2002-01-11 2002-07-13 2003-01-12 $2000.00 Window Closed / Lapsed
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