N9912A参数转换算法详细信息

如您所述，S11的“Z Conv”或阻抗转换计算为：Zconv = Z0 *（1 + S11）/（1-S11）其中S11是复数。
用户可以使用“Refl”设置明确选择此转换例程，或者因为S11是反射测量，“Refl”等式将通过“Auto”设置选择。
（'Auto'和S21（在像N9923A这样的矢量框上）将选择'Trans'等式。）Z0是Meas Setup - > Settings中的“System Zo”设置。
你能详细说明哪些不适合你吗？
Wil而且为了完整性，'Trans'等式为：Zconv = 2 * Z0 *（1-S21）/ S21用户可以明确选择将此传输方程与S11一起使用，尽管物理解释留给用户！
当S21或S12是当前S参数选择时，“自动”设置选择该传输方程。
同样，用户可以用S11覆盖'自动'设置，并选择'Trans'来使用传输方程。
同样，这意味着留给用户。
参考：微波元件测量手册，Joel P. Dunsmore，第117-118页。编辑：wils于2014年7月25日下午3:35



     以下为原文

  As you state, "Z Conv" or impedance conversion for S11 is computed as:

Zconv = Z0 * (1+S11) / (1-S11)

where S11 is a complex number.

This conversion routine is either chosen explicitly by the user with the "Refl" setting, or because S11 is a reflection measurement, the "Refl" equation will get chosen by the 'Auto' setting.  ('Auto' and S21 (on a vector box like N9923A) will chose the 'Trans' equation.)

Z0 is the "System Zo" setting found in Meas Setup -> Settings.

Can you elaborate on what is not working for you?

Wil

And just for completeness, the 'Trans' equation is:

Zconv = 2 * Z0 * (1-S21) / S21

A user can explicitly choose to use this transmission equation with S11, though the physical interpretation is left to the user!  The 'Auto' setting chooses this transmission equation when S21 or S12 is the current S-parameter selection.  Likewise, a user may override the 'Auto' setting with S11 and choose 'Trans' to employ the the transmission equation.  Again, the meaning of this is left to the user.

Reference: Handbook of Microwave Component Measurements, Joel P. Dunsmore, pp 117-118.

Edited by: wils on Jul 25, 2014 3:35 PM

我正在测量s11的短RG58电缆。
我用51欧姆电阻校准了系统。
我得到以下开放电缆的结果（例如2 MHz）：s11（log）= -0.010144668415134;
s11（lin）= 0.999457763和Z（线性，测量）= 807.454895159684。
另一方面，如果我使用s11和你在下面提到的公式手动计算阻抗，我得到Z非常大（大约188000），因为分母非常小（1-s11（lin））。
我必须做错事......为了排除小数字的错误，在范围的另一边（21Mhz），我测量s11（lin）= 0.943895889，我计算为1718ohm而不是直接用FieldFox测量的64ohm。
顺便说一句，测量的Z是正确的，因为当与用短端电缆测量的Z相乘时，我得到大约50欧姆的Z0。
我很困惑......谢谢



     以下为原文

  I am measuring s11 for a short RG58 cable. I have calibrated the system with a 51 ohm resistor. I get the following result for the open cable (at 2 MHz for example):  s11(log) = -0.010144668415134; s11(lin) = 0.999457763 and Z(linear,measured) = 807.454895159684. On the other hand, if I manually calculate the impedance using s11 and the formula you mention below, I get Z extremely big (around 188000) because the denominator is very small (1-s11(lin)). I must be doing something wrong...
To exclude the mistake of small numbers, on the other side of the range (at 21Mhz), I measure s11(lin)=0.943895889 which I calculate as 1718ohm instead of 64ohm measured directly with FieldFox. Btw, the measured Z is correct because I get around 50 ohm for Z0 when multiplying with with the Z measured for a cable with the short-end. I am puzzled...

Thanks

你好。
我在计算中发现了错误 - 对我感到羞耻。
我只使用s11（mag），而不是在我的等式中使用s11作为复数。
一切都很好，谢谢你的帮助！
当然，FieldFox是完全正确的！



     以下为原文

  Hi. I found the mistake in my calculations - shame on me. I was using s11(mag) only, instead of using s11 as a complex number in my equation. All is fine, thanks for your help! FieldFox is perfectly right, of course!

大！
很高兴我能帮助澄清。



     以下为原文

  Great!  Glad I could help clarify.