两个PXIe VNA M937xA可配置进行差分测量吗？

是 - 当您将2个PXI M937xA模块配置为4端口VNA时，您可以进行所有标准4端口测量，包括平衡/差分参数。
我们将支持标准拓扑结构：SE-BAL SE-SE-BAL BAL-BAL BAL-SE但是所有这些差分测量都将在单端激励条件下进行（即一次激励1个端口，而不是真差分模式）。
对于无源差分设备（如以太网电缆），这是一种完全有效的测量方法（使用叠加原理）。



     以下为原文

  yes - when you configure 2 PXI M937xA modules as a 4-port VNA, then you are allowed to make all the standard 4-port measurements, which includes the balanced/differential parameters.  we will support the standard topologies:

SE-BAL
SE-SE-BAL
BAL-BAL
BAL-SE

however all these differential measurements will be made under single-ended stimulus conditions (i.e 1 port stimulated at a time and not True Differential mode).  for passive differential devices (like an Ethernet cable) this is a perfectly valid way of making the measurements (using the superposition principle).

BrianCam Hitachi当你说“非真正的差分模式”时，这是因为没有巴伦，（巴伦是一种将平衡阻抗转换为不平衡的设备，反之亦然。此外，巴伦也能提供阻抗变换，因此称为巴伦变形金刚
）在PXIe VNA M937xA中？
因此，“有效的测量方法（使用叠加原理）。”
SW生成的补偿与校准相结合，进行以下Diff S参数测量：BAL-BAL ??
谢谢Brian



     以下为原文

  BrianCam Hitachi

When you say "not True Differential mode", is this because there is no Balun, (Balun is a device which converts balanced impedance to unbalanced and vice versa. In addition, baluns can also provide impedance transformation, hence the name Balun Transformers) in the PXIe VNA M937xA's ??

Hence, 
"valid way of making the measurements (using the superposition principle)." is a SW generated compensation combined with Calibration to make the following Diff S- parameter measurements: BAL-BAL??

Thanks Brian

> {quote：title = briancamhitachi写道：} {quote}> BrianCam Hitachi >>当你说“非真正的差分模式”时，这是因为没有巴伦，（巴伦是一种将平衡阻抗转换为不平衡的设备，反之亦然
此外，平衡 - 不平衡变压器还可以在PXIe VNA M937xA中提供阻抗变换，因此命名为Balun变压器。
>当您没有_多端口网络分析仪时，Baluns用于进行差分测量。
例如，如果您只有2个端口VNA，并且想要测量差分滤波器的s参数，则可以在VNA的每个端口上使用平衡 - 不平衡转换器将每个单端端口转换为差分端口。
在这样的设置中，您必须从最终测量中去嵌入平衡 - 不平衡变换器的s参数，以获得滤波器的真实响应。
但是，如果你有一个4端口VNA，则不需要巴伦。
我会推荐这个_ *应用笔记* _。
它解释了进行多端口/平衡测量的单端和真差分方法，并描述了这两种技术之间的差异。



     以下为原文

  > {quote:title=briancamhitachi wrote:}{quote}
> BrianCam Hitachi
> 
> When you say "not True Differential mode", is this because there is no Balun, (Balun is a device which converts balanced impedance to unbalanced and vice versa. In addition, baluns can also provide impedance transformation, hence the name Balun Transformers) in the PXIe VNA M937xA's ??
> 

Baluns are used in making differential measurements when you _don't have_ a multiport network analyzer.  for example if you only have 2 port VNA and you want to measure the s-parameters of a differential filter, you could use a balun on each port of the VNA to convert each single-ended port to a differential port.  in such a setup, you would have to de-embed the s-parameters of the balun from your final measurement to get the true response of the filter.  However, if you have a 4-port VNA, there is no need for a balun.  

I would recommend this _*Application Note*_.  it explains both the single-ended and true differential approach to making multiport/balanced measurements and describes the differences between the two techniques.