Electronic String Instrument Pitch and Tone Control

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Solution Overview

Problem

Conventional music playing devices fail to detect and reproduce the subtle changes in tone and pitch caused by varying degrees of string pressing, which are essential for authentic guitar and fretless instrument performances.

Innovation Solution

An electronic string instrument equipped with electrostatic sensors and a digital signal processing system that detects the string-press position and vibration levels, allowing for precise control of pitch and tone through a CPU-driven process that combines data from hexaphonic pickups and electrostatic pads to simulate the effects of finger pressure and movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional zero-crossing period detection method is used, then pitch detection is achieved, but the degree of string pressing is not detected

Engineering Contradiction:
Improvepitch detection accuracyVSAvoidstring press degree information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the detection function into two independent parts: zero-crossing period detection for pitch and string press degree detection for tone control. This allows each detection method to operate independently and provide specific information without interfering with the other, resolving the contradiction between achieving pitch accuracy and capturing press degree information.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent makes the waveform analysis system multi-functional by extracting both pitch information (from zero-crossing periods) and tone information (from string press degrees) from the same input signal. This universal approach allows a single detection system to serve multiple purposes, simultaneously achieving pitch detection and tone control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If string is pressed harder to increase tension, then pitch is raised, but subtle tone changes cannot be reproduced

Engineering Contradiction:
Improvepitch variation detectionVSAvoidtone control capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by continuously monitoring string press degree and using this information to control tone parameters in real-time. The system feeds back the detected press degree information to adjust the electronic tone generation, enabling subtle tone changes that respond dynamically to the player's finger pressure variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter from binary (pressed/not pressed) to continuous (degree of pressing). By measuring the analog string press degree and using it to modulate tone parameters, the system enables subtle tone variations that correspond to the continuous range of finger pressures applied by the musician.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If left hand pressing degree is not detected, then device complexity is reduced, but authentic guitar performance cannot be reproduced

Engineering Contradiction:
Improvedetection system simplicityVSAvoidreal guitar performance reproduction
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces complex mechanical detection systems with electronic waveform analysis. Instead of using mechanical sensors to detect string press degree, the system uses electronic analysis of the plucked string's waveform characteristics, specifically the relationship between maximum and minimum values, to infer press degree information non-invasively.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the string itself to provide the detection information needed. By analyzing the natural waveform characteristics of the plucked string (maximum and minimum values), the system uses the string's own vibration properties to reveal press degree information, eliminating the need for separate detection mechanisms.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate reproduction of subtle tone and pitch variations based on string pressing, providing a more authentic electronic instrument experience that mimics real guitar and fretless performances.

Implementation Method 1

electrostatic sensors and a digital signal processing system that detects the string-press position

Methodology Applied
Scientific EffectElectrostatic field detection: Electrostatics

Implementation Method 2

combines data from hexaphonic pickups and electrostatic pads

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2814025B1Music playing device, electronic instrument, and music playing method
Publication Date: 2017.11.01 CASIO COMPUTER CO LTD
  • EP2814025B1 patent drawingFigure 1
  • EP2814025B1 patent drawingFigure 2
  • EP2814025B1 patent drawingFigure 3

AI summary

A CPU detects an operation state on a fingerboard at a prescribed period, stores the detected operation state in a memory every time an operation state is detected, detects whether or not any of a plurality of extended strings has been struck, determines a pitch of a note to be played based on the operation state stored in the memory in response to a string being struck, and controls a note to be played in a sound source based on the detected operation state and the operation state stored in the memory every time the operation state is detected after a command to play a note of a determined pitch is issued to the sound source.