Bounds for the rth characteristic frequency of a beaded string or of an electrical filter.
The fundamental mode of vibration of a beaded string has a shape without change of sign. The rth higher normal mode of vibration has r changes of sign. Given any virtual shape of the string with r changes of sign, an algorithm is found that gives upper and lower bounds for the rth characteristic frequency as a function of the virtual shape. By making a certain transformation it is found that this algorithm holds for the characteristic frequencies of an inductor-capacitor network. Other transformations show that it applies to the rth eigenvalue of a Hermitian matrix.
School of Mathematics, Georgia Institute of Technology, Atlanta, Georgia 30332.
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Barnsley
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Duffin