【摘要】 串扰是电气、电子系统内部多导体传输线间的相互电磁干扰,严重时可降低系统的可靠性和安全性,影响系统的正常工作。典型的多导体传输线包括电缆线束和PCB导线等,其远端串扰问题显得尤为突出。针对多导体传输线系统的远端串扰噪声,提出了一种在中低频段大幅消除远端串扰的理论及其实现方法,考虑将两段传输线通过一有源网络级联,两段传输线线长比例可调,并且该网络可通过特别设计,以达到传输线远端端口不含其他导线耦合噪声的目的。另外提出一种"部分移相网络",即对"施扰线"电压进行移相处理而对其余端口不做处理,该网络满足上述串扰消除的要求,并且对于任意传输线系统均存在最优的移相角和线束比例。为了确定最优移相角和最佳线长比例,基于数值计算提出了最优移相角和最佳线长比例的计算流程,并结合两个示例进行了仿真测试与实验测量。研究表明,中低频段最优移相角集中在π附近,且随着频率的升高而增大;最佳线长比例则集中在0.3~0.5之间,两者均与频率有关。更多还原

【Abstract】 Crosstalk is a kind of mutual electromagnetic interference(EMI) among transmission lines in electric or electronic system, which can decrease the reliability and safety of the system and influence its normal work in severe cases. As typical multiconductor transmission lines(MTL), the farend crosstalk(FEXT) problem of cable bundles and PCB wires is extremely prominent. Aiming at FEXT noise, a FEXT cancellation method and its realization in middle and low frequency range are proposed in this paper. Considering two transmission lines cascading by a special designed network, which can be specially adjusted the length ratio, the voltage of far-end port will not contain coupled noise of other ports. Furthermore, the partial phase shift network(PPSN) which carry on certain phase shift on aggressor lines but do nothing to victim lines is satisfied with the FEXT cancellation, and the optimum phase shift angle and length ratio exist. To find out the optimum angle and ratio, calculation procedures are proposed in this paper based on numerical operation, which is simulated and verified by two practical cases. It is illustrated that 1) the optimum phase shift angle is around π in middle and low frequency range and increases with frequency; 2) the optimum length ratio is between 0.3-0.5, and both of that is closely related to frequency.更多还原