Touch Sensing Device for Accurate Sound Emission Timing
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Solution Overview
Problem
Conventional electronic musical instruments face challenges in accurately synchronizing sound emission timings with key presses, especially when multiple sounds are generated simultaneously, due to increased processing burdens on CPUs, leading to inconsistencies in sound emission.
Innovation Solution
A touch sensing device with first and second contacts at each key, a reception section for closed sense signals, counters for duration measurement, a comparator for timing comparison, and a controller for sending sound emission instructions, allowing for accurate sound emission timing based on key press velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sound emission timing is controlled by CPU processing in conventional electronic pianos, then the device can emit sound, but the processing burden increases when multiple sounds are generated simultaneously, leading to inconsistent sound emission timings
Solution Approach 1:
The patent divides the sound emission control function into separate hardware components: a first counter for velocity measurement, a second counter for timing control, and a comparator for timing comparison. This segmentation transfers timing-critical functions from the CPU to dedicated hardware circuits, reducing CPU processing burden and ensuring consistent sound emission timing even when multiple keys are pressed simultaneously.
Solution Approach 2:
The patent replaces software-based CPU processing with hardware-based counter circuits and comparators for timing control. The counters and comparators operate in hardware to generate sound emission timing signals, substituting the mechanical/CPU processing approach with an electronic hardware approach that provides more reliable and consistent timing.
2Productivity
If the second contact is disposed above the lower limit of the key to enable early sound emission detection, then velocity information can be obtained, but sound is emitted before the key is fully pressed, creating timing discrepancy with acoustic piano
Solution Approach 1:
The patent uses the second contact disposed above the key's lower limit to preliminarily detect key press velocity and prepare timing information. However, the actual sound emission is delayed until the key reaches its lower limit position, as determined by the comparator comparing the second counter value with the attainment duration value. This preliminary detection followed by delayed execution resolves the contradiction between early detection and accurate timing.
3Reliability
If the key weight and inertial moment are reduced to maintain rapid playability and avoid malfunctions, then the electronic piano is more reliable, but the sound emission timing becomes earlier than acoustic piano
Solution Approach 1:
The patent implements a feedback mechanism where the second counter measures the actual time from first contact closure to key lower limit attainment, and the comparator uses this measured time (attainment duration value) to control the sound emission timing. This feedback-based timing adjustment compensates for the differences caused by lighter key weight and lower inertial moment, synchronizing sound emission timing with acoustic piano characteristics.
Data Source
AI summary
A first contact and a second contact are provided at each of a plurality of keys, and are successively closed in accordance with a key press operation. On the basis of respective closed sense signals from the first contact and the second contact, a duration from when the first contact is closed until the second contact is closed is counted as a first count value and then a duration after this counting has ended is counted as a second count value. An attainment duration value and the second count value are compared, and when a predetermined condition is satisfied, a control signal is outputted. When this control signal is received, sound emission information instructing an emission of a sound by a sound emission controller is sent. The sound emission information includes touch information based on the first count value.