With the development of electrical and electronic technology, the increasing popularity of home appliances and electronic products, radio and television, telecommunications and computer networks become increasingly developed, increasingly complex electromagnetic environment and deterioration, making electrical and electronic products, electromagnetic compatibility (EMC electromagnetic interference EMI and electromagnetic anti-EMS) problem by governments and the growing importance of manufacturing enterprises. European government regulations, January 1, 1996, all electrical and electronic products must pass EMC certification, CE marking before the EC market. This widespread influence in the world, governments have taken measures to electrical and electronic products RMC mandatory performance management. According to the EU's Electromagnetic Compatibility (EMC) Directive 83/336/EEC, all in the EU market of electrical and electronic products to other products in its foreign interference and influence immunity in strict compliance with EU legal requirements.