Establishment And Research Of 1/f Noise Model For MET Low Frequency Seismometer

Seismic exploration is a commonly used and very effective method in petroleum,natural gas and geologic exploration.The performance of seismometer directly determines the application prospect of seismic exploration.After years of oil and gas development,conventional seismic exploration has been unable to meet the growing energy demand,and constrain the development of seismic exploration technology bottleneck on the seismic exploration is seismometer.The current market is the mainstream of the seismometer is equipped with solid mass electromechanical seismometer,but because of its own principles,in low-frequency field,the traditional mechanical and electrical low-frequency seismometer with internal structure is very complex,expensive,anti-poor interference ability and the basic dependence on imports.Compared with conventional electromechanical seismometer,MET seismometer has the advantages of simple structure,high sensitivity and low frequency signal detection.At present,the technology is not mature.Due to its different principle,the output signal of the core components is very weak and can be easily submerged by noise.Thermal noise as a white noise its value by the external temperature changes,can be compensated by the conditioning circuit.And 1 / f noise is related to its own structure.Therefore,this paper mainly focuses on the research of 1 / f noise and provides theoretical support for the optimization design of MET seismometer.The core of this article is as follows:(1)MET seismometer testing machine design.First of all,according to the existing research,production and processing of this study required MET seismometer test prototype.Based on a large number of literatures,combined with the current domestic processing level,the LTCC process is used to sample the core sensitive chip,And then the structure design and fabrication of the detector are described in detail,and the production of the MET seismometer detector is completed.(2)1/ f noise analysis of MET seismometer testing machine.Firstly,the noise components of the MET seismometer are analyzed.And the low noise test system of the MET seismometer is designed for the noise characteristics of the detector.The self-noise of the detector is tested and the self-noise test data is obtained.According to the noise test data,the actual 1 / f noise data is extracted by wavelet transform,and the 1 / f noise parameters of the MET seismometer are estimated by the least squares method.(3)Influence of basic parameters of MET seismometer on 1/ f noise.Based on the structural characteristics of the core components and the working principle,the mathematical model of the single-channel reaction chamber principle is established by theoretical deduction.And the multi-physics simulation model is established by the finite element method.The MET multi-physics simulation model can fully display the detailed information of the physical parameters in the core cavity under the same excitation condition.The integral distribution function can directly convert the surface distribution of the charged ion electrode into the current density distribution to represent the simulation model output signal.The output signal includes two external excitation signals and noises(due to thermal noise and temperature,so in the case of constant temperature,we temporarily believe that the thermal noise for the excitation generated signal).Then,the same external excitation is applied to the MET multi-physics simulation model,and the 1 / f noise is only related to its internal charge convection,diffusion and migration phenomena.Therefore,the size of the 1 / f noise is judged by the output signal size of the multi-physics simulation model.Based on the multi-physics simulation model,the influence of the basic parameters such as the core component structure,the electrolyte concentration and the bias voltage on the 1 / f noise of the MET seismometer is analyzed.Finally,the optimal design scheme of the detector is provided.