UNCORRECTED性能怎么样

戴夫，你测量的是测量耦合器的物理特性。
是的，耦合器具有响应曲线，可将其动态范围降至840 MHz以下。
图表上50 MHz的损耗是典型的。
戴夫



     以下为原文

  Dave,

What you are measuring is the physical characteristics of the measurement couplers.   Yes, the couplers have a response curve that reduces it's dynamic range below 840 MHz.   The loss at 50 MHz on your graph is typical.

Dave

> {quote：title = dhamilton写道：} {quote}> Dave，>>你测量的是测量耦合器的物理特性。
是的，耦合器具有响应曲线，可将其动态范围降至840 MHz以下。
图表上50 MHz的损耗是典型的。
>>戴夫谢谢戴夫。
我理解为什么耦合器的电气特性随频率而变化，但我认为默认工厂校准的目的是纠正这种系统误差 - 是不是这样？
我知道建议在软盘上备份出厂校准数据。
我假设当我没有执行用户校准时会使用这些数据，因此耦合器的效果会在软件中得到纠正。
也许我误解了默认调用的目的。
我一直想知道为什么我在低频时会得到一些不好的结果，并且开始怀疑仪器有故障，但看起来并非如此 - 只是该仪器的限制。
无论如何，谢谢你的帮助。
我很高兴我不必担心一大笔维修费用！
戴夫



     以下为原文

  > {quote:title=dhamilton wrote:}{quote}
> Dave,
> 
> What you are measuring is the physical characteristics of the measurement couplers.   Yes, the couplers have a response curve that reduces it's dynamic range below 840 MHz.   The loss at 50 MHz on your graph is typical.
> 
> Dave

Thank you Dave. 

I understand why the electrical characteristics of the couplers change with frequency, but I thought the purpose of the default factory calibration was to correct for such a systematic error - is that not the case? 

I know one is advised to keep a backup of the factory calibration data on a floppy. I assumed it was this data that would have been used when I've not performed a user cal, and so the effect of the couplers would have been corrected for in software. 

Perhaps I have mis-understood the purpose of that default callbration. 

I've been wondering why I get some poor results at low frequencies, and was beggining to suspect the instrument had a fault, but it appears this is not the case - just a limitation of that instrument. 

Thank you anyway for your help. I'm glad I don't have to worry about a big repair bill !

Dave

在开发时，如果8720，工厂校准的想法是相当有争议的，所以只包括损失偏移，并没有尝试完全补偿耦合器响应。
令人担心的是，补偿会显示噪声基底在低​​频下滚动，这可能会让人感到不安。
我们克服了这一点，现在因子cal也补偿了耦合器的滚降。
也许从8720ES开始，但肯定是在所有PNA和ENAs编辑：Dr_joel于2013年1月9日晚上11:13



     以下为原文

  At the development time if the 8720, the idea of a factory calibration was quite controversial, so only loss offsets were included, and no attempt made to fully compensate for coupler response.  The fear was that the compensation would show the noise floor rolling UP at low frequency, and that might upset people.

We got over that, and now factor cal compensates for coupler roll-off too.  Maybe started in the 8720ES but for sure it is in all PNA and ENAs

Edited by: Dr_joel on Jan 9, 2013 11:13 PM

> {quote：title = Dr_joel写道：} {quote}>在开发时如果8720，工厂校准的想法很有争议，所以只包括损失补偿，并没有尝试完全补偿耦合器响应。
令人担心的是，补偿会显示噪声基底在低​​频下滚动，这可能会让人感到不安。
谢谢。
这使得现在更有意义。
戴夫



     以下为原文

  > {quote:title=Dr_joel wrote:}{quote}
> At the development time if the 8720, the idea of a factory calibration was quite controversial, so only loss offsets were included, and no attempt made to fully compensate for coupler response.  The fear was that the compensation would show the noise floor rolling UP at low frequency, and that might upset people.

Thank you. That makes more sence now. 

Dave