VNA的噪声系数是什么

我不知道你的VNA，但看一下这个帖子：非主题，但是这里有一个很好的论坛来测量噪声系数问题吗？
Dr_joel告诉我如何计算8720D的NF。
*至于8720：易于计算NF：* *动态范围在10 Hz IF BW中约为100 dB或在1 Hz当量中为110。
kTB = 174，因此174-110 =噪声系数= 64 dB *。
令人惊讶的是，在8720D的情况下，NF有多高，但毫无疑问，你有一个非常不同的VNA，事情可能会有很大不同。
很明显，一些VNA能够进行噪声系数测量，如果VNA的噪声系数高于器件的增益，这是不可能的。
我会对一些安捷伦员工的反应感兴趣，因为我对这个主题感兴趣。
戴夫
编辑：drkirkby于2012年10月6日下午6:07



     以下为原文

  I don't know your VNA, but take a look at this thread:
Off-topic, but is there a good forum here for noise figure meter questions?
 

where Dr_joel told me how to calculate the NF of my 8720D. 

*As to 8720: easy to compute NF:*

*Dynamic range is about 100 dB in 10 Hz IF BW or 110 in 1Hz equiv. kTB=174, so 174-110=noise figure=64 dB*. 

I was amazed how high the NF was in the case of the 8720D, but no doubt you have a very different VNA, and things might be quite different. It's clear some VNAs are capable of noise figure measurements, which would not be possible if the noise figure of the VNA was higher than the gain of the device. 

I'll be interested in what response you get from some of the Agilent staff, as I have some interest in this topic. 

Dave
 
Edited by: drkirkby on Oct 6, 2012 6:07 PM

> {quote：title = Dr_joel写道：} {quote}>对噪声系数的两个主要影响是：接收器类型和耦合因子。
>>有三种或四种常见接收器类型，最差到最佳：> 1）基于采样器：非常高的噪声系数 - 8753和8720使用采样器工作在VCO的200至300次谐波> 2）高次谐波混频器（或
低谐波采样器） - 许多毫米波系统使用它;
谐波操作高达10或12或更多> 3）低谐波混频器 - PNA在26.5GHz以上的分析仪中使用三次谐波混频，PNA-L在13 GHz以上使用它，我认为。
> 4）基本混合 - 噪声系数最低。
>>耦合因子范围从50 dB（在微波耦合器的低端，接近10 MHz）到12 dB（在高端）> 8753使用16 dB，ENA类似但具有更接近的高功率版本
到20 dB。
>>将耦合系数添加到分析仪的噪声系数中，您就得到了整体噪声系数。
Fieldfox N9923A使用什么样的接收器？
由于电池耗尽和尺寸，我预计会有相当多的妥协。



     以下为原文

  > {quote:title=Dr_joel wrote:}{quote}
> Two principal impacts on noise figure are: receiver type and coupling factor.
> 
> There are three or four common receiver types, for worst to best:
> 
> 1) Sampler based: very high noise figure - 8753 and 8720 use samplers operating on 200th to 300th harmonic of the VCO
> 2) High harmonic mixer (or low harmonic samplers) - many mm-wave systems use this; operation on harmonics up to 10 or 12 or more
> 3) Low harmonic mixer - PNA uses third harmonic mixing in analyzers above 26.5GHz,  PNA-L uses it above 13 GHz, I think.
> 4) Fundamental mixing - Lowest noise figure.
> 
> The coupling factor ranges from 50 dB (at the low end of the microwave couplers, near 10 MHz) to 12 dB (at the high end)
> 8753 uses 16 dB, ENA is similar but has a high power version that is closer to 20 dB.
> 
> Add the coupling factor to the noise figure of the analyzer and you have the overall noise figure.


What sort of receiver does the Fieldfox N9923A use? I expect there has to be quite a few compromises on that due to battery drain and size.

从根本上说是混合的。



     以下为原文

  Fundamentally mixed.

E5071B使用什么接收器类型？
这种类型的噪声系数大致是什么？



     以下为原文

  What receiver type is used in the E5071B?  What would the noise figure of this type be, roughly?

我相信它是基于混音器的。
我猜它在40 dB范围内，包括耦合器效应。



     以下为原文

  I believe it is mixer based.  I would guess it is in the 40 dB range including coupler effects.

对不起，我的帖子在这里。
这是在另一个VNA论坛（关于编程）的意思。
我不知道怎么回复它导致这个消息出现在这个线程下DaveEdited：drkirkby于2012年10月11日下午2:14



     以下为原文

  Sorry for the post of mine here. It was mean to be in another VNA forum (about programming). I've no idea how replying to it there caused the messsage to appear under this thread 

Dave

Edited by: drkirkby on Oct 11, 2012 2:14 PM