Harmonic analyzer
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For its time, Henrici's analyzer was precise and easy to use. Dayton Miller of the Case School of Applied Sciences used it in his work in acoustics and the theory of music beginning in 1908, and would analyze thousands of sound waves with the device. | For its time, Henrici's analyzer was precise and easy to use. Dayton Miller of the Case School of Applied Sciences used it in his work in acoustics and the theory of music beginning in 1908, and would analyze thousands of sound waves with the device. | ||
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| + | Rolling-sphere integrators work in essentially the same way as modern mechanical mice: the rolling motion of a ball on a two dimensional surface is broken down into rectangular coordinates for measurement. | ||
Revision as of 17:03, 21 March 2006
In 1894, Olaus Henrici (1840-1918) of London devised a harmonic analyzer for finding the fundamental and harmonic components of complex sound waves. It consists of multiple glass spheres, called rolling-sphere integrators, connected to measuring dials. The image of a sound wave is placed under the device. The user moves a mechanical stylus along the curve's path, tracing out the wave form. As the stylus moves along the changing amplitude, the rolling-sphere integrators rotate, such that the first integrator rotates once over the entire length of the curve, representing the fundamental wavelength. Subsequent integrators rotate additional revolutions, with the fifth and final integrator turning fives times over the entire length of the curve. The end result is an instrument capable of computing the first ten Fourier coefficients of the curve, the maximum often necessary in studying sound waves.
For its time, Henrici's analyzer was precise and easy to use. Dayton Miller of the Case School of Applied Sciences used it in his work in acoustics and the theory of music beginning in 1908, and would analyze thousands of sound waves with the device.
Rolling-sphere integrators work in essentially the same way as modern mechanical mice: the rolling motion of a ball on a two dimensional surface is broken down into rectangular coordinates for measurement.
