IEC插值纠错是如何工作的?

> {quote：title = TheGris写道：} {quote}>我想了解PNA上的插值纠错，包括旧的（8720D / 8753E）和新的（N5241A / N5242A）。
>> * _Q1 - 什么是插值算法？_ * >>>或者插值更复杂？
相当复杂一点。
我们称之为圆弧插值，它实质上是矢量空间中的插值。
确切的算法是专有的。
我在本书的第3章中提供了更多的细节和几个例子（我知道，老话说，但信息确实存在）：http：//www.wiley.com/WileyCDA/WileyTitle/productCd-
1119979552.html >> * _Q2 - Interpolation Accuracy_ *>安捷伦非常谨慎地说明，当您设置INTERP（IEC）时，不能保证纠错的准确性。
但是......没有任何东西可以告诉你降级有多糟糕。
>我从手册中了解到，（a）当您插入的校准中每1 GHz有67个（实际）校准点时，IEC是“最准确的”;
并且（b）如果相移大于每5个数据点180度，则插值不起作用。
>>是否有任何（合理的）指南可用于使插值成为有用的功能？
如果每米测试端口电缆每5 MHz有1个点，则通常会满足VNA的指定性能（因此，如果您有两个1米的测试端口电缆，则每2.5 MHz需要一个点）。
>> _ * Q3 - 在HOLD模式和插值中更改“刺激”参数* _ >>当您处于HOLD状态（无触发，无新扫描）时，可以更改启动频率，停止频率和点数，并且它可以正常工作
如果IEC /插值为ON。
接受更改，但数据保留旧值。
较新的分析仪甚至不会更新刺激设置，直到获得新的扫描。
插值对测量数据没有影响，它只影响误差项。
您没有插入数据，而是在新的频率范围和点数上插入误差项，然后在更新显示之前必须获取新的原始数据（通过扫描）。
>>在我看来，插值时唯一的精度降低来源是非插值扫描线中的校准点与数据点处于完全相同的频率 - 而不是（必然）插值时......
>> _ * Q4 - 是否有解决这些问题的文件？
安捷伦或第三方？* _>为什么是，如上面的链接所示。
>提前致谢!!!
回想起来，非常欢迎你。



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  > {quote:title=TheGris wrote:}{quote}
> I would like to gain an understanding of interpolated error correction on the PNAs, both old (8720D/8753E) and new (N5241A/N5242A).
> 
> *_Q1 - What is the interpolation algorithm?_*
> > Or is the interpolation more complicated?
Quite a bit more complicated.  We call it circular interpolation which is essentially an interoplation in vector space. The exact algorithms are proprietary.  I give quite a few more details and several examples in Chapter 3 of my book (I know, getting old saying that, but the info really is all there): http://www.wiley.com/WileyCDA/WileyTitle/productCd-1119979552.html
> 
> *_Q2 - Interpolation Accuracy_*
> Agilent has been VERY careful to state only that when you set INTERP (IEC) on the accuracy of the error correction is not guaranteed. But... there is NOTHING that tells you how badly it is degraded.
> I know from the manuals that (a) IEC is 'most accurate' when there are 67 (real) calibration points per 1 GHz in the calibration you are interpolating from; and that (b)  interpolation doesn't work if the phase shift is more than 180 degrees per 5 data points.
> 
> Are there any (reasonable) guidelines that can be used to make interpolation a useful feature?
If you have 1 point every 5 MHz for each meter of test port cable, you will typically meet the specified perfomance of the VNA (so if you have two, 1 meter test port cables, you will need a point every 2.5 MHz).


> 
> _*Q3 - Changing "stimulus" parameters in HOLD mode and Interpolation*_
> 
> The start freq, stop freq, and number of points can be changed when you are in HOLD (no trigger, no new sweeps) and it works if IEC/interpolation is ON. 
The changes are accepted, but the data is held with the old values.  Newer analyzers don't even update the stimulus settings until a new sweep is acquired.  Interpolation has NO effect on measured data, it only effects the error terms.  You are not interpolating the data, you are interpolating the error terms over the new frequency range and number of points, and then new raw data must be acquired (through a sweep) before the display is updated.
> 
> It seems to me that the ONLY source of accuracy degradation when interpolating is the fact that the calibration points in a non-interpolated sweep line are at the exact same frequencies as the data points - and not (necessarily) when interpolating...
> 
> _*Q4 - Is there any documentation that addresses these issues? Agilent or 3rd party?*_
>
Why yes, as noted in the link above. 
> Thanks in advance!!!
You are most welcome, in retrospect.

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