石英晶体谐振频率测试理论研究及系统设计

The Theory Study of the Resonant Frequency of Quartz Crystal and the Designing of the Measurement System

负载测试状态的晶体元件谐振参数测试精度受测试网络参数影响较大。本项目基于π网络零相位法,在测试系统设计中引入补偿网络,减小π网络以及测试插座的杂散阻抗对测量结果的影响。同时,在软件设计方面,对测试系统进行标定,以减小系统误差。测量结果表明,随晶体的标称频率的增加,其负载谐振频率的相对方均差呈逐渐增大趋势。与目前国际上较先进的250C系统测量结果比较,最大测量偏差小于4×10^(-6)。但是,当晶体标称频率较大(100 MHz)时,系统重复性测量精度较差,最大偏差达10×10^(-6)。

The distribution parameters of π network are very important on the measurement of the resonant frequency of quartz crystal. In order to increase its measuring accuracy, the compensating network is considered in the measuring system. In addition, the measuring system is calibrated when the software of the system is designing. The results show that as the frequency of the quartz crystal is bigger, relative mean square error is increasing. Comparing to the results of the 250C system, the biggest deviation is less than 4× 10-6, but the accuracy of repeated measuring is worse when the frequency is bigger.