鉴相型容栅传感器由偶次谐波所引起的原理性测量误差的分析

Principle Error Analysis of Phase Modulated Capacitive Transducer Arising from Even Harmonics

本文以付里叶分析方法,对鉴相型容栅传感器的输出函数v(t,x)进行了典型分析,发现了由偶次谐波所引起的原理性非线性测量误差,并指出其原因在于C_i(x)的构造,即容栅尺电容极板的几何构造.因此在进行容栅尺电容极板的几何构造设计时,必须使其C_i(x)的偶次展开项的系数最小,从而使原理性测量误差为最小,这就是设计时必须依据的准则之一。

A typical analysis for the output function V(t, x) of phase modulated capacitive transducers is per- formed by the Fourier Method. It is found that there is a non-linear principle error arising from even harmonics, which is determined by the structure of the function C_1(x), i.e. the geometrical structure of the elec- trodes of the capacitive transducer. Therefore, one of the criterions, which have to be actted on in the struc- ture design of the electrodes of capacitive transducer for displacement measurement, is that the coefficients of even expansions of C_1(x) be minimum in oder to reduce the principle error.