静电悬浮加速度计检测线路设计及实验研究  

Design and experiment of the detection circuit for electrostatically levitated accelerometers

作　　者：吴黎明[1] 董景新[1] 韩丰田[1] 

机构地区：[1]清华大学精密仪器与机械学系,北京100084

出　　处：《仪器仪表学报》2006年第12期1569-1572,共4页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(40504010)资助项目

摘　　要：本文首先介绍静电悬浮加速度计在国内外的发展现状以及在空间技术中的应用,然后介绍静电悬浮加速度计的基本工作原理。针对测量微弱差动电容ΔC的检测线路进行设计,建立了用于调制ΔC的变压器电流电桥的等效电路模型,导出了用于调制信号放大的宽带放大电路的放大倍数KAC,分析了采用2路TTL同步方波信号控制4路单刀单掷模拟开关的解调电路工作过程,估算了滤波电路的截止频率f-3dB,使得解调信号在工作频带fs内基本保持0 dB增益,在高于载波频率f0上获得较大的衰减。实验结果表明,该检测线路实际灵敏度为0.601 mV/fF,考虑线路固有噪声和寄生电容的影响,最小分辨率达到1.06 fF。This paper introduced the development of electrostatic levitation accelerometer （ELA） and its application in space nowadays. After ELA＇s basic working principle was generalized, the detection circuit of ELA was designed in order to detect very weak differential capacitance signal △C. The equivalent circuit model of the current transformer bridge was set up, in which differential capacitance was modulated, and then the gain KAC in wideband amplifying circuit was deduced, which was used to magnify the weak modulated signal. In the demodulating process, quad single-pole/single-throw analogue switches, which were controlled by two synchronizing TTL square waves, were adopted. The cut-off frequency f-3dB of the low pass filter was evaluated so as to keep 0 dB gain in the range of working frequency f, and get much attenuation in the frequencies higher than the carrier frequency f0. Experiments showed that the detection circuit＇s sensitivity was 0. 601 mV/fF. Accounting for the circuit inherent noise and parasitic capacitance, the minimal resolution approached 1.06 fF.

关 键 词：静电悬浮 加速度计 变压器电桥 宽带放大 相敏检波 

分 类 号：P223.6[天文地球—大地测量学与测量工程]