| 摘要 |
PROBLEM TO BE SOLVED: To provide a string vibration detection sensor which detects string vibration and in which overtone component ratios with respect to fundamental tone components included in its output are relatively large. SOLUTION: This string vibration detection sensor 10 is provided with a base body 11, permanent magnets 21 to 26 and magnetic sensing devices 31 and 32. The permanent magnets 21 to 26 are arranged and fixed to each corner part of two squares S1 and S2 adjacent to each other, so as to form a rectangle RT, the top faces of the permanent magnets 21, 23 and 25 are south poles, and the top faces of the permanent magnets 22, 24 and 26 are north poles. The magnetic sensing devices 31 and 32 are arranged at the centers of gravity of the squares S1 and S2 respectively, and their outputs are to be combined. Thus, an output of the sensor 10 vibrates, while having a frequency which is twice as high as that of a string ST, when the string ST vibrates within an x-y plane, and also, the waveform of the output becomes sharp to include a lot of overtone components to a fundamental tone components, when the string ST goes through over the permanent magnets 22 and 25.
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