MHD角速度传感器预处理电路的低噪声设计方法研究

Study on MHD Angular Rate Sensor's Preprocessing Circuit Low Noise Design Method

为改善磁流体动力学(MHD)角速度传感器的噪声性能,研究预处理电路的低噪声设计方法。采用3个并联的SSM-2220双极型晶体管对作为输入级,级联低噪声集成运放构成差分放大电路,作为前置放大器,后级加入低通滤波、交流耦合和单端转差分电路。建立了预处理电路的噪声模型,并进行了噪声测量实验,电路的输入噪声电压谱密度约为0.6 n V/Hz(1/2)(1 k Hz)。提出的低噪声预处理电路将MHD角速度传感器等效输入噪声水平降低至nV/Hz(1/2)量级。

In order to improve the noise performance of a Magnetohydrodynamics（MHD）angular rata sensor,low noise design method for a preprocessing circuit is researched. Using three parallel SSM-2220 bipolar transistor pairs as input stage,cascaded low noise integrated operational amplifier constitute a differential amplifier circuit as a preamplifier. Low pass filter,AC coupling and single ended to differential circuits are used as last stage. The noise model of preprocessing circuit is established and the noise measurement experiment is carried out. The result shows that the circuit ’ s input noise voltage density is about 0.6 nV/ Hz （1 kHz）.The proposed low noise preprocessing circuit reduce the equivalent input noise level of MHD angular rata sensor to nV/ Hz magnitude.