The Electromagnetic Shielding Design Of AV3921 TEMPEST Test Receiver

Electro Magnetic Compatibility (EMC) has become essential technical guideline and performance criterion of electric and electronic products in many fields. For the sake of information safety, aiming at electronic products of national defense and confidential departments, all countries constituted directive procedure in term of secrecy deign criterion to restrain information leakage and satisfy the transient electromagnetic pulse radiation standards. TEMPEST technique is used to control electromagnetic emission (transmitting and radiation), which is not functional and may threaten working task, to keep electromagnetic information from leaking. In china, there are some research and production of products and equipments according to TEMPEST standards, but there are still no TEMPEST measurement equipments.TEMPEST measurement receiver is highly requested in EMC because of its use. In this paper, in allusion to the structure of AV3921 TEMPEST test receiver, EMC of both unitary system and each functional module was studied, interfering sources and susceptive modules were distinguished, typical characters of hole and gap electromagnetic leakage and coadjacent electromagnetic leakage were analyzed, and EMC of digital signals module and RF module were deeply analyzed. Layout of all modules was done on the basis of above study and analysis.Effects of hole and gap structures on shield efficiency were studied considering electromagnetic shielding means, and a fastening measure was used to deal with holes and gaps in box. Multi-conductor cable model was advanced based on transmitting line theory, Coadjacent cable fastening methods were advanced.In this paper, establish models and simulate, and simulating results conformed to actual measure results.Experiences obtained in this study provided a reference to EMC design of high sensitivity broadband test receiver.