【摘要】 针对压电加速度计的本底噪声,以压电变换器和电荷放大器为研究对象,建立压电变换器单自由度弹簧-质量-阻尼机械谐振系统力学模型和压电元件的电学模型,以结型场效应管(JFET)为核心元件,研究电路中的主要噪声源,建立各自的噪声模型。利用En-In噪声模型构建方法将电路内部噪声源等效到输入端,同时将Y-Δ变换原理引入T型偏置网络的噪声分析中。利用噪声模型推导出压电加速度计噪声谱密度表达式,将获得的实验数据与利用表达式得到的理论计算值进行对比,验证表达式的有效性与正确性。通过此表达式分析影响加速度计噪声的关键因素,总结出加速度计低噪声设计原则,为提高加速度计的信噪比提供理论基础。更多还原

【Abstract】 This paper focuses on the noise floor of piezoelectric accelerometer,takes the piezoelectric transducer and charge amplifier as study objects,and establishes the mechanical model of piezoelectric transducer single degree of freedom spring-mass-damping mechanical resonance system and the electrical model of piezoelectric element. The Junction Field Effect Transistor( JFET) is taken as the core element to study the main noise source in the circuit,and establish the respective noise model for each source. The construction method of En- Innoise model is used to make the inner noise source of the charge amplifier equivalent to the input port; meanwhile,the Y-Δtransformation theory is introduced into the noise analysis of T type bias network. The noise model is used to deduce the noise spectrum density expression of the piezoelectric accelerometer. The experiment data and the theoretical calculation values obtained from the expression were compared,which verifies the effectiveness and correctness of the expression. Using this expression,the key factors affecting the accelerometer noise are analyzed,the low noise design principle of the accelerometer is summarized,which provides a theoretical basis for improving the noise- signal ratio of the accelerometer.更多还原