静电悬浮加速度计噪声测试数据的频谱分析方法

分析了不同系数的离散傅里叶变换公式的含意,并从中筛选出符合工程分析要求的正确公式.为使用快速傅里叶变换可采用多种方式使数据符合2的整数次幂,分析了各种方法的优缺点;分析了各种频谱的应用对象,得出静电悬浮加速度计噪声适宜采用功率谱密度,且在窗函数应用上宜选择与之符合的系数;给出了使用OriginLab公司Origin 5.0/7.0软件计算功率谱密度时所必须采取的纠正措施,提出地面测试静电悬浮加速度计噪声需采用差分方法以抑制环境噪声,具体操作方法是,将两台加速度计已扣除平均值的时域噪声值相减后除以2~(1/2).

Method for Spectral Analysis of Electrostatically Suspended Accelerometer Noise Data

The signification of discrete Fourier transform formulae with different coefficient is analyzed and the formula proper for engineering analysis is screened out.There are more ways to make the sample amount fit integral power of 2 for using fast Fourier transform.The strongpoint and the shortcoming of these ways is discussed.The applied objects of various frequency spectra are analyzed,the power spectral density is suitable for the noise of the electrostatically suspended accelerometer and the corresponding coefficient of window method should be selected.The correcting which must be used when the power spectral density is calculated by commercial software"Origin 5.0/7.0"of OriginLab Corporation is presented.The difference measurement of the noise of the electrostatically suspended accelerometers is required to bate the influence of environment noise in Ground.It is demonstrated that the differential method should be as follows:the noise of twin accelerometers in time domain,from which already deducted the average value,is subtracted mutually, whereafter is divided by 2~(1/2).