Design Of Electromagnetic Compatibility For Wireless Seismometer

Seismic exploration has always been an important means in the exploration of the earth,and seismic exploration instruments are the most indispensable part.In the actual exploration process,the harsh working environment requires the instrument to meet the electromagnetic compatibility.Under the premise of ensuring its stable operation,it is necessary to obtain pure and undistorted seismic data,and explain the underground structure truthfully.At present,the wireless seismometer,which developed independently by Jilin University,realizes real-time data recovery,frees the trouble of heavy cables,realizes the miniaturization and lightness of the instrument.However,due to the inadequate design of the internal module and the overall layout of the PCB,there is electromagnetic interference in the interior.So it is urgent to design its electromagnetic compatibility.The main contents of this paper are as follows:Firstly,the electromagnetic compatibility of the wireless seismometer is analyzed theoretically.The electromagnetic compatibility principle,the three elements of electromagnetic interference and the coupling principle of electromagnetic interference are studied in detail.Through the modeling and calculation of different coupling modes,the respective suppression measures are put forward,which provides a theoretical basis for the subsequent design.PCB is an important part of the instrument,and its electromagnetic compatibility directly affects the overall performance of the instrument.Through the analysis of the basic structure of PCB,the causes and suppression methods of electromagnetic interference on PCB are summarized in three aspects: layer number,component characteristics and transmission line.The introduction of PCB layering,layout and wiring design principles are followed electromagnetic compatibility design provides technical support.Combined with the actual requirements of the wireless seismometer and the aforementioned theory and design principles,the instrument is divided into functions.And the electromagnetic compatibility design is carried out from the power module,the GPS timing module,the wireless transmission module,the acquisition module and the RF module.At the same time,the optimization design is made from the level of PCB.After the design is completed,the designed PCB board is simulated and optimized.After testing and calculating the electromagnetic compatibility index,the shielding effect is tested.Finally,the whole instrument is tested in the actual fracturing monitoring,which proves that the instrument has good electromagnetic compatibility.