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标题: Effective Z0 与 Impedance Z0 为什么不一样？ [打印本页]

作者: Dz久久 时间: 2011-10-16 16:00
标题: Effective Z0 与 Impedance Z0 为什么不一样？
各位大虾，小弟想请教一个问题。
在我用HyperLynx仿真的之前，设置好了目标阻抗Z0，当用Terminator Wizard计算匹配电阻的时候，实际的有效电阻（Effective Z0）却比目标阻抗（Impedance Z0 ）小，不知道这是为什么？

作者: sdody 时间: 2011-10-17 11:55
The average metal Z0 is not the same as the effective impedance of a trace. The Average Zo is Average impedance of the whole trace
The "effective Z0" is a figure that attempts to show by how much the selected nets actual characteristic impedance is effectively lowered by the presence of IC capacitance along the net and associated nets. This value can be used as a guide when choosing termination resistances, since for nets that are significantly loaded by IC capacitance, the proper termination value is almost always lower than suggested by the nets actual Z0.

走线的impedance（Z0) 受到IC impedance 影响= Effective Impedance.
Effective Impedance 一般比走线Impedance 低

作者: Dz久久 时间: 2011-10-25 19:54

sdody 发表于 2011-10-17 11:55 1 `* o# P# Q4 B/ L- S/ {
The average metal Z0 is not the same as the effective impedance of a trace. The Average Zo is Avera ...

多谢啊~{:soso_e100:}

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