一种弦式接收仪频率参量计量校准方法研究

Research on frequency parameter calibration method of vibrating wire readout

基于弦式接收仪激励信号电压幅值超出标准信号发生装置量程上限的问题,提出一种弦式接收仪频率参量计量校准方法,采用低频信号发生器为标准信号发生装置,由数字示波器判定弦式接收仪激励信号形式,通过设计对称式信号调理模块,根据激励信号电压幅值大小调整衰减倍数,在全量程范围内实现了弦式接收仪频率参量的计量校准。通过试验验证,该方法可准确判别弦式接收仪的激励信号形式、量程上下限位置,在不影响测量精度的前提下将激励电压降至安全幅值以内,频率最大示值误差0.11 Hz,3000 Hz测量点处测量不确定度U=0.22 Hz,k=2,满足最大允许误差0.3 Hz要求。

Based on the problem that the voltage amplitude of the excitation signal of the vibrating wire readout exceeds the upper limit of the range of the standard signal generator,a frequency parameter calibration method was proposed.A low-frequency signal generator was taken as the standard signal generator,the excitation signal form of the vibrating string frequency reader was determined by designing the symmetrical signal conditioning module,and the attenuation multiple was adjusted according to the voltage amplitude of the excitation signal.Then the calibration of frequency parameters of vibrating wirereadout was realized in the full range.The experimental results show that this method can accurately distinguish the excitation signal form and the upper and lower limits of the measuring range of the vibrating wire readout instrument,reduce the excitation voltage to the safe amplitude without affecting the measurement accuracy.The maximum indication error of the frequency is 0.11 Hz,and the measurement uncertainty at the 3000 Hz measuring point is U=0.22 Hz,k=2,which are less than the maximum allowable error of 0.3 Hz.