The main research objects of electromagnetic compatibility are: ① various human noise, such as transmission line corona noise, car noise, contactor self noise, noise caused by conductor discharge during opening, electrical locomotive noise, urban noise, etc The mutual influence of various public utility equipment (transmission lines, communication, railways, highways, petroleum metal pipelines, etc.) within the shared corridor Reflection problems caused by large buildings such as super high-rise buildings, transmission lines, and iron towers. ④ The effects of electromagnetic environment on humans and various organisms. This includes the influence of power frequency fields such as strong wires, medium, short wave, and microwave electromagnetic radiation. ⑤ The impact of nuclear electromagnetic pulses. The electromagnetic pulse generated by high-altitude nuclear explosions can extensively damage command, control, communication, computer, and alarm systems on the ground TEMPEST technology. The substantive content is a series of research work carried out on the electromagnetic radiation and information leakage issues of information equipment, from the perspectives of information reception and protection Misoperation of electronic devices. To prevent misoperation, measures must be taken to improve the anti-interference ability of the equipment Spectrum allocation and management. Radio spectrum is a limited resource, but it is not consumable. It needs to be scientifically managed and fully utilized Electromagnetic compatibility and measurement Natural influences, etc. Measures to improve electromagnetic compatibility: ① Using a complete shielding body can prevent external radiation from entering the system and also prevent the interference energy of the system from radiating outward. The shielding body should maintain integrity, and essential doors, seams, ventilation holes, and cable holes must be properly handled. The shielding body should have reliable grounding Design a reasonable grounding system, with small signal, large signal, and interference generating circuits grounded separately as much as possible, and grounding resistance as small as possible Using appropriate filtering techniques, the passband of the filter is reasonably selected to minimize leakage losses as much as possible When using amplitude limiting technology, the amplitude limiting level should be higher than the working level and should be bidirectional. ⑤ Correctly select connecting cables and wiring methods, and replace long cables with optical cables if necessary. ⑥ Adopting technologies such as balanced differential circuit, shaping circuit, integral circuit, and gate circuit. ⑦ The system frequency allocation should be appropriate. When multiple main frequency signals are working in a system, try to avoid the frequency of each signal, or even avoid the resonance frequency of the other party. ⑧ When conditions permit, various equipment in shared corridors should maintain a large separation distance to reduce the impact on each other