[互助]designer 中内部变量freq如何使用

designer中为电路赋值时，其中电阻阻值要考虑高频时趋肤效应，即阻值依赖于频率，阻值的计算公式中要包含系统频率，即系统内部变量freq, 这样的要求如何实现呢？直接把freq写进公式中总提示出错

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。该如何解决呢？查找到帮助，看不明白该如何用…… pY!dG-;  
Frequency-Dependent Resistor Instance Netlist Syntax j)tCr Py  
The general form for a frequency-dependent resistor instance is: =#Cf5s6qt  
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Rxxxx n1 n2 [modelname] [R=]'freq-dependent-expr' X]pWvQ Q]  
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[[TC1=]val] [[TC2=]val] [M=val] [SCALE=val] r;on0wm&B  
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n1 is the positive node and n2 is the negative node of the resistor. The current is assumed to flow from n1 through the resistor to n2. If a model card is provided for the resistor, the modelname is its name. The modelname is identified by matching it to the .MODEL statements in the netlist. fJ&<iD)6  
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The frequency-dependent expression should be enclosed in single quotation marks. This expression calculates the resistance as a function of the token f, or as a function of any value with units Hz. The circuit frequency is available to the model each time the model equations are evaluated. The label R= is optional. The first unlabeled value after a modelname is taken to be the resistance value. B?lBO V4v4  
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The syntax above shows the labels TC1= and TC2= as optional, but this option depends on the presence or absence of the resistance value, labeled or unlabeled: J={OOj  
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•  When both modelname and the resistance value are present but the resistance value does not have the R= label, the next two unlabeled values are taken to be TC1, then TC2. To specify a value for TC2, either a value .. OT}Yr9h4  
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哪位高人给指点一下？这个问题困了我好久了