冲击加速度峰值测量中低通滤波器截止频率的影响

中国航空工业第一集团公司北京长城计量测试技术研究所,北京100095摘要为了得到冲击测量系统中低通滤波器截止频率对冲击加速度峰值测量结果的影响。本文采用Matlab编程语言,对冲击测量系统中的二阶巴特沃斯型低通滤波器进行仿真,得到对应不同低通滤波器截止频率的冲击加速度峰值测量结果。通过对比测量结果的误差和冲击输入信号的幅频响应,分析不同截止频率对冲击加速度峰值测量结果的影响,得到结论:冲击测量系统中低通滤波器截止频率的选择,应根据测量系统的动态特性和实际冲击输入信号波形的具体形状和变化趋势来合理选择,以满足冲击加速度测量不确定度的要求。

Effect of the Lowpass Filter Cut-off Frequency on the Shock Acceleration Calibration

In order to study the effect of cut-off frequency of the low-pass filter on the peak value of the shock acceleration, Matlab programming language was used to emulate the biquad Butterworth low pass filter to get different test peak value of shock acceleration corresponding to the varied cut-off frequency of the low-pass filter. By comparing the error of test point and the amplitude-frequency property of the shock input signal, the relation between the cut-off frequency and the peak value of the shock acceleration was analyzed. The results indicated that the cut-off frequency of the low-pass filter should be chosen according to the dynamic characters of the measurement system as well as the waveform shape and the changing trend of the input signal to meet the measurement uncertainty requirement of the shock acceleration.