Modeling And Simulation Of Fifth Order Electrostatic Force System For All-digital Output Of MEMS Acceleration Sensor

With the rapid development of today's science and technology,Micro Electro Mechanical System(MEMS)acceleration sensors have become an indispensable and important achievement in the contemporary world.They play an enormous role in all fields of today's society and have irreplaceable value.MEMS accelerometers,as representatives of the world's most sophisticated technologies,can also create practical value for various fields in the country.The growing development of MEMS technology makes the accelerometers occupy smaller and smaller volumes,and the accuracy can be higher and higher.Many things that could not have been imagined have become possible.All civilian mobile phones,commercial oil exploration,and military missiles use MEMS acceleration sensors.In this dissertation,the three modules of the all-digital output fifth-order electrostatic force system of MEMS acceleration sensor for petroleum exploration are studied.1)The physical conduction analysis of the signal detection module is carried out,from the input acceleration signal to the capacitance change size,and then the change from the reading circuit to the voltage change from the capacitance change.Finally,the output of the system is fed back to the sensitive mass in the form of static electricity.The mathematical formula is deduced,and the step response of the moving equation of the sensitive mass block is analyzed.2)Describes the history of Sigma-Delta modulators and analyzes their operating principles.Using MATLAB and Simulink,completes third-to-fifth order system design,parameter adjustment,and modeling simulation of the entire signal detection module with Sigma-Delta modulators.and use MATLAB's GUI tool making software to simplify the entire system design process;3)For the 1-bit bit stream output by the above fifth-order system,in order to restore the original input waveform to visually observe the signal,a digital decimation filter bank composed of a CIC filter,a compensation filter and a half-band filter is designed.And use the Filterbuilder toolbox to generate the model in Simulink,and perform the joint modeling simulation with the first two modules.Finally,the digital decimation filter bank is implemented on the RTL level in the Verilog hardware language,and simulations are performed using two software models,Modelsim and Quarters II.In this thesis,the design of all-digital output fifth-order electrostatic force system of MEMS accelerometer is adjusted to the parameters of Sigma-Delta modulator.The signal-to-noise ratio in the output signal bandwidth reaches 152.4 dB in the case of 128 times oversampling and one quantized output.dB,after the digital decimation filter,the signal-to-noise ratio of the output signal to the input signal bandwidth is 152.0 dB.The result shows that the system successfully implements the functions of 24-bit output and digital signal processing to meet the design requirements.