Sources of interference , interference pathway and EMI sensitive equipment are the three elements formed in the high-speed circuit -sided circuit board design, electromagnetic compatibility design around three main elements unfold .
For a single high speed circuit board, the common electromagnetic interference include the following four kinds :
① power supply noise.
② ground noise.
③ high-frequency electromagnetic radiation interference device itself .
④ signal transmission line crosstalk. By analyzing the basic formation of the three elements of EMI can be considering the overall design of the high-speed circuit -sided line of thinking .
First, the single-sided circuit board size determines the position of components on the board , single-sided circuit board size directly affects the possibility of EMI generated . Secondly, for the position of special components should give priority and OK. Finally , to ensure the consistency condition signal circuit flows.
Distinguish circuit functional unit , the size of the rational design of various functional areas , usually , high-speed circuit -sided EMI circuit board has the following four kinds of interference patterns : ① coupled conduction disturbances . ② crosstalk interference. ③ radiation coupling interference. ④ mismatch radiation interference lines. To make the high-speed circuit -sided circuit board design to meet the EMC requirements, improve EMI performance optical transmission system , must take appropriate measures to deal with components and increasing the intensity of the line high-speed circuit -sided circuit board , thereby improving reliability and stability of the optical transmission system .
Reduce external electromagnetic radiation and improve the ability of anti-electromagnetic interference is the key to EMC , and reasonable layout and wiring design priority. In the actual design, the design should be based on the requirements and design specifications, using reasonable measures against electromagnetic interference , to make a comprehensive and integrated consideration, in order to design a high-speed circuit -sided circuit boards with good EMC performance .
