THERMAL NOISE IN PRECISION ROTORS

被引:6
作者
BERNARD, BE [1 ]
WINKLER, LI [1 ]
RITTER, RC [1 ]
机构
[1] UNIV VIRGINIA,DEPT PHYS,CHARLOTTESVILLE,VA 22901
关键词
NOISE; ACOUSTIC; -; Measurements;
D O I
10.1088/0026-1394/21/3/003
中图分类号
TH7 [仪器、仪表];
学科分类号
0804 ; 080401 ; 081102 ;
摘要
A first, simple theory of thermal fluctuations of ideal rigid rotors is presented, along with some representative measurements and analysis of a real rotor. The ideal rotor has a power spectrum of fractional frequency fluctuations with two regions. At low frequency it is flat, and at high frequency it varies as omega minus **2. A related measure, the level of fluctuations as a function of measuring time (the Allan variance), is presented. Our present magnetically suspended rotors are shown to have an excess noise amplitude of about 10**4 times the ideal level. 'Electronic cooling' by feedback can provide great improvement in both the noise amplitude and spectral behavior of the ideal rotor.
引用
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页码:115 / 126
页数:12
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