这个FieldFox有问题吗？

我刚刚更新了固件 - 首先是版本4.01，然后是7.27，S21的基本问题仍然存在，尽管频率和幅度有所改变。
通过测试端口之间的短跳线，S21在721.76 MHz处的峰值增益为+2.892 dB，在2641.12 MHz处的峰值增益为6.6 dB。
每个端口有50欧姆负载，S21在5550 MHz时显示-50.5 dB的峰值。
这不是噪音。
我在端口2上放了一个频谱分析仪，看看是否有任何垃圾从该端口流出，这可能会导致接收器认为没有信号时会有信号，但是我无法测量任何信号。
如果我能发明一些在同轴电缆上获得3 dB增益的方法，那将是非常好的。
我想这会让我成为一个有钱人！
但不知怎的，我怀疑FieldFox正在撒谎。
如果安捷伦*的某人能够确认我正确使用此功能，我将会非常有帮助 - 即假设CalReady应确保仪器在开启时在测试端口校准 - 忽略预热时间等。我认为这使用了仪器
需要退回给卖家，但最好能获得专家意见。
戴夫



     以下为原文

  I've just updated the firmware - first to version 4.01, then to 7.27, and the basic problem on S21 still exists, although the frequencies and magnitudes have changed a bit. 

With a short jumper between the test ports, S21 shows a peak gain of +2.892 dB at 721.76 MHz, and a loss of 6.6 dB @ 2641.12 MHz. 

With 50 Ohm loads on each ports, S21 shows a peak value of -50.5 dB @ 5550 MHz. It is not noise. I put a spectrum analyzer on port 2, to see if there was any rubbish coming out of that port which might cause the receiver to think there is a signal when there is not one, but I can't measure anything. 

It would be really nice if I could invent some way of getting 3 dB gain down a bit of coax. I guess it would make me a rich person! But somehow I suspect this FieldFox is lying. 

I would be *really helpful if someone from Agilent* can confirm I am using this correctly - i.e. in assuming that the CalReady should ensure that the instrument is calibrated at the test ports from switch on - ignoring warmup period etc. 

I think this used instrument needs to be returned to the seller, but it would be nice to get an expert opinion on this. 

Dave

谢谢Afsi。
我很惊讶CalReady无法察觉两个端口之间的损失程度。
他有一个8752A，它真的很旧，我相信它是用特定的电缆校准的。
那就是说，我从未见过那种乐器。
Em，不是一个令人印象深刻的动态范围规格！
我希望一些更昂贵的组合单位做得更好。
无论如何，谢谢你确认单位没问题 - 他会对此感到高兴。
顺便说一下，固件从3.06更新到7.27之后有一个惊喜。
该装置现在配备了干扰分析仪，选项236，它以前从未有过！
我不确定当我从3.06升级到4.01，或从4.01升级到7.27时是否出现过这种情况，但在某个地方它已经获得了一个它以前从未有过的选项。
祝你2014年也好。戴夫



     以下为原文

  Thank you Afsi. 

I'm surprised a CalReady could not be aware of the magnitude of the loss between two ports. He has an 8752A, which is really old and I believe that is per calibrated with a specific cable. That said, I have never seen that instrument. 

Em,  not a very impressive dynamic range spec!  I'd hope some of the more expensive combination units do better.

Thank you anyway for confirming the unit is OK - he will be pleased about that. 

BTW, there was a pleasant surprise after the firmware was updated from 3.06 to 7.27.  The unit now has the interference analyzer, option 236, which it never had before! I'm not sure if that appeared when I upgraded from 3.06 to 4.01, or from 4.01 to 7.27, but somewhere it has gained an option it certainly never had before. 

Best wishes to you too for 2014. 

Dave

> {quote：title = drkirkby写道：} {quote}>谢谢你Afsi。
>>我很惊讶CalReady无法察觉两个端口之间的损失程度。
他有一个8752A，它真的很旧，我相信它是用特定的电缆校准的。
那就是说，我从未见过那种乐器。
我不确定为什么N9912A没有相同或类似的CalReady。
有一点需要注意的是，安捷伦销售的大多数台式VNA并不真正具有CalReady，而是一些名为Mixer Cal的内部产品。
Mixer Cal实现了内部标准化，因此您的S参数看起来相当准确。
没有匹配校正（与CalReady一样）。
然而，台式VNA的良好硬件最终会为您提供不错的测量，即使没有匹配校正的校准也是如此。
> Em，不是一个令人印象深刻的动态范围规格！
我希望一些更昂贵的组合单位做得更好。
他们好多了。
例如，我附上了三个6 GHz FieldFox的动态范围的比较。
此致，Afsi



     以下为原文

  > {quote:title=drkirkby wrote:}{quote}
> Thank you Afsi. 
> 
> I'm surprised a CalReady could not be aware of the magnitude of the loss between two ports. He has an 8752A, which is really old and I believe that is per calibrated with a specific cable. That said, I have never seen that instrument. 

I am not sure why N9912A does not have an equivalent or similar CalReady.  One thing to note is that most benchtop VNAs that Agilent sells don't really have CalReady, but something internall called Mixer Cal. Mixer Cal implmenets an internal normalization, so that your S-parameters look reasonably accurate. There is no match correction (as there is with CalReady). However, the good hardware of the benchtop VNAs ends up giving you decent measurements, even without a cal with match correction.

> Em,  not a very impressive dynamic range spec!  I'd hope some of the more expensive combination units do better.

They are much better. For example, I've attached a comparison of the dynamic range of three 6 GHz FieldFoxes.

Regards,
Afsi

附件

• DR.PNG13.8 KB
  

> {quote：title = am95405写道：} {quote}>我不确定为什么N9912A没有等效或类似的CalReady。
我有点惊讶，因为在开机时在测试端口实施校准不是火箭科学。
尽管如此，他确实至少拥有HP N cal套件，我制造的SMA套件和QuickCal选件。
>有一点需要注意的是，安捷伦销售的大多数台式VNA并不真正具有CalReady，而是内部称为Mixer Cal的东西。
Mixer Cal实现内部标准化，因此您的S参数看起来相当准确。
没有匹配校正（与CalReady一样）。
然而，台式VNA的良好硬件最终会为您提供不错的测量，即使没有匹配校正的校准也是如此。
我相信他所拥有的8752A台式VNA在预热后会进行校准。
有一种方法可以使用85032B校准套件验证性能，但是您不需要校准套件来使用VNA，这与大多数台式VNA完全不同。
>> Em，不是一个非常令人印象深刻的动态范围规格！
我希望一些更昂贵的组合单位做得更好。
>>他们好多了。
例如，我附上了三个6 GHz FieldFox的动态范围的比较。
是的，这是一个巨大的差异 - 其他型号的性能提升了51分贝。
事实上，N9912A的特定频率似乎特别糟糕，似乎表明可能缺乏过滤功能。
我猜这就是为什么这个模型很便宜。
顺便说一句，我想到为什么干扰分析获得了这个选项。
我怀疑1）为仪器购买的选项2）出于安​​全原因，仪器重置为某种出厂默认值，因此固件非常老旧。
3）旧固件不支持该选项，但在固件更新时它变得生动。
无论如何，他有一个我不知道他有的选择。
>问候，> Afsi谢谢你Afsi。



     以下为原文

  > {quote:title=am95405 wrote:}{quote} 
> I am not sure why N9912A does not have an equivalent or similar CalReady.  

I'm a bit surprised, as it can't be rocket science to implement a calibration at the test ports at switch on. Still, he does have at least an HP N cal kit, an SMA one I made, and the QuickCal option. 

> One thing to note is that most benchtop VNAs that Agilent sells don't really have CalReady, but something internall called Mixer Cal. Mixer Cal implements an internal normalization, so that your S-parameters look reasonably accurate. There is no match correction (as there is with CalReady). However, the good hardware of the benchtop VNAs ends up giving you decent measurements, even without a cal with match correction.

I believe the 8752A benchtop VNA he has is calibrated after it is warmed up. There is a way of verifying the performance using an 85032B calibration kit, but you don't need a calibration kit to use the VNA, which is quite different to most benchtop VNAs as you say. 

> > Em,  not a very impressive dynamic range spec!  I'd hope some of the more expensive combination units do better.
> 
> They are much better. For example, I've attached a comparison of the dynamic range of three 6 GHz FieldFoxes.

Yes, a  dramatic difference - up to a 51 dB improvement on the other models. The fact there are specific frequencies the N9912A seems particularly bad, seems to indicate there might be a lack of filtering. I guess that is why the model is quite cheap. 

BTW, I thought about why that option was gained for the interference analysis. I suspect 

1) Option purchased for the instrument
2) Instrument reset to some sort of factory defaults for security reasons, so firmware was very old. 
3) The old firmware did not support the option, but it came to life when the firmware was updated. 

Anyway, he has got an option I did not know he had. 

> Regards,
> Afsi

Thank you Afsi.

> {quote：title = drkirkby写道：} {quote} >>> BTW，我想到为什么干扰分析获得了这个选项。
我怀疑>> 1）为仪器购买的选件> 2）出于安​​全原因，仪器重置为某种出厂默认值，因此固件非常陈旧。
> 3）旧固件不支持该选项，但它在固件更新时生效。
>>无论如何，他有一个我不知道他有的选择。
我认为这个选项可能会在几天内演示它可能会关闭。



     以下为原文

  > {quote:title=drkirkby wrote:}{quote}

>
> 
> BTW, I thought about why that option was gained for the interference analysis. I suspect 
> 
> 1) Option purchased for the instrument
> 2) Instrument reset to some sort of factory defaults for security reasons, so firmware was very old. 
> 3) The old firmware did not support the option, but it came to life when the firmware was updated. 
> 
> Anyway, he has got an option I did not know he had. 

I think that option is probably a demo in a few days it will probably turn off.

> {quote：title = drkirkby写道：} {quote}>我相信他所拥有的8752A台式VNA在预热后会进行校准。
有一种方法可以使用85032B校准套件验证性能，但是您不需要校准套件来使用VNA，这与大多数台式VNA完全不同。
是的我有一个，我更换了原来没有的原装电缆后，用85032B对我的HP 8752A进行了内部调整和校正常数。
而且我不再需要校准它，因为常数相同，校准或没有校准我得到了相同的结果。
使用相同的85032B校准执行验证。
套件。
所以说我不知道​​如何使用相同的校准套件和验证过程进行验证，可能Joel可以告诉我们更多相关信息。



     以下为原文

  > {quote:title=drkirkby wrote:}{quote}

> I believe the 8752A benchtop VNA he has is calibrated after it is warmed up. There is a way of verifying the performance using an 85032B calibration kit, but you don't need a calibration kit to use the VNA, which is quite different to most benchtop VNAs as you say. 

Yes I have one and I did the internal adjustments and correction constants with the 85032B to my HP 8752A after changing the original cable which I never had. And I do not need to calibrate it anymore as the constants are the same, calibration or without calibration I got the same result. The verification is performed with the same 85032B cal. kit. So said that I have no idea how can you verify with the same cal kit and what the verification proccess does, probably Joel can tell us more about this.