such as Sigrity PowerSI, allows the user to place ports at the nodes of interest in the layout, and extract electrical circuits, generally in the form of S-parameters or detailed Spice subcircuits. There is usually no hard limit to the number of ports that can be defined for the extracted circuit, so it is straightforward to extract a "literal" circuit comprised of a through channel of interest coupled with a number of aggressor signals。。。这段英文你能理解就知道该怎么弄了