通过8722ES进行测量时表现奇怪

请在8722上选择“步进扫描模式”。然后阅读我的书并查找“IF延迟”项目。
这是由与DUT延迟相关的扫描动态引起的。
由于您在测量时测试的是相同的扫描，因此扫描动态是相同的，并且它们没有显示错误。
当您测量具有不同延迟的DUT时，扫描动态效果会发挥作用。
当您使用步进扫描模式时，它们将被删除。



以下为原文

please select "step sweep mode" on the 8722. Then read my book and look for the item "IF delay".

this is caused by sweep dynamics related to the delay of the DUT. Since you test the same thru as you measure, the sweep dynamics are the same and their is no error shown. when you measure a DUT with a different delay, sweep dynamic effects come into play. when you use step sweep mode, they are removed.

我有一个类似的VNA - 20 GHz 8720D，并且在传输和反射测量方面都有一些峰值。
请参阅：测量短路时导致这些尖峰的原因是什么？
乔尔认为这可能是+“采样器弹跳”+，我没有像他说的那样用衰减器进行调查。
*我真的需要接受他的建议。*我怀疑这可能是原因，因为这些是在我添加选项012（直接接收器访问）的时候开始的，这意味着通过前面板使用前面板将信号从桥接器路由到接收器
* 4个内部2.4毫米至SMA电缆* 2个前面板SMA-SMA跳线。
我不知道8722ES是否默认启用步进扫描模式，但我的8720D确实如此，但我仍然看到这些令人讨厌的尖峰。
顺便说一句，如果你有一些NMD到N适配器，你可以完全消除电缆。
我希望你能找到2.4毫米NMD到N的适配器，虽然在8720D我使用3.5毫米NMD到N适配器。
戴夫



以下为原文

I have a similar VNA to you - the 20 GHz 8720D, and have got some spikes both on transmission and reflection measurements. See:
What causes these spikes when measuring a short?

Joel thought it might be +"sampler bounce"+, which I have not investigated with the attenuator like he said. *I really need to take his advice.* I suspect that could be the cause, as these started around the time I added option 012 (direct receiver access), which means routing the signal from the bridges to the receivers via the front panel using

* 4 internal 2.4 mm to SMA cables
* 2 front panel SMA-SMA jumpers.

I don't know if the 8722ES defaults to step sweep mode being on, but my 8720D does, yet still I see these annoying spikes.

BTW, if you get some NMD to N adapters, you could eliminate the cables entirely. I expect you can find 2.4 mm NMD to N adapters, although on the 8720D I use 3.5 mm NMD to N adapters.

Dave

你好，戴夫，非常感谢你的建议。
我今天尝试了步骤模式，但是尖峰并没有消失。
有时S21上的尖峰可以完全消失，并在同一个地方转到S12侧。
开始觉得真的“VNA伏都教科学”））。
我试图强调更多的内部衰减器，改变功率电平范围等但完全没有影响。
我的8722ES在前面板上只有一个SMA-SMA跳线，（R-channel In-out）你提到了NMD适配器，我可以完全消除电缆。
现在我不明白。
我的8722ES两个端口都有2.4mm NMD（公）。
我还有所有可能的Keysight适配器套件85130C，85130D，85130F，85130G。
即使将任何测试端口适配器连接到我的VNA测试端口，我也必须使用某种测试端口电缆。
测试端口适配器如何消除电缆的影响。
对不起，也许我不正确理解？
你可以解释吗？
如果你设法检查内部的2.4mm-SMA电缆，请给我一张照片。
所有可能的想法都不仅仅是受欢迎的。
Tuomas编辑：bar28于2016年2月23日上午7:51



以下为原文

Hello Dave,

Huge thanks your advices. I tried today step sweed mode, but spikes not disappeared. Sometimes spikes on S21 can disappear totally and goes to S12 side on the same place. Starting to feel really "voodoo science of VNA" )). I tried to stress more internal attenuator, changing power level ranges etc but no effect at all. My 8722ES have only one SMA-SMA jumpper on the front panel, (R-channel In-out)

You mentioned about NMD adapters, that I can elimenate cables completely. Now I not understood. My 8722ES has 2.4mm NMD (male) on both ports. I have also all possible Keysight adapter kits 85130C, 85130D, 85130F, 85130G. Even connecting any test port adapters to my VNA test port I must use some kind of test port cables. How test port adapters can eliminate effect of the cables. Sorry, maybe I not understood correctly? Can you explain?

If you manage to check internal 2.4mm-SMA cablings, please take them a a photo to me. All possible ideas are more than a welcome.

Tuomas

Edited by: bar28 on Feb 23, 2016 7:51 AM

谢谢戴夫，现在我理解你的观点了。
我必须检查，如果我能找到这样的适配器。
当我有空的时候，我可以毫无问题地检查电缆。
我可以尝试做的一件事是，如果它使采样器更稳定，我可以减少一点测试端口功率。
我现在使用的最大默认预设功率电平为-10dBm。
8722ES由安捷伦进行了年度校准，并且符合规格。
验证过程已经完成了相当少的频率点，并且这种0.05dB的变化仍然在不确定性窗口内。不幸的是，安捷伦在其校准证书上没有测量出有问题的频率点。
Tuomas编辑：bar28于2016年2月23日上午10:31



以下为原文

Thanks Dave, now I understood your point. I have to check, if I can find such an adapters.
When I have time again, I can check cablings without any problem. One thing I can try to do, that
I can decrease a bit test port power if it makes sampler more stable. I have used now the maximum
default preset power level which is -10dBm.

8722ES is calibrated annualy by Agilent and it's in specs. Verification process has done rather less
frequency points and such a 0.05dB variation still goes inside uncertainty window..unfortunately just
the problematic frequency point is not measured by Agilent on their calibration certificate.

Tuomas

Edited by: bar28 on Feb 23, 2016 10:31 AM

我通过所有内部2.4mm-SMA半导体电缆，仔细清洁并连接回正确的扭矩。
不幸的是，对痕迹上的尖峰没有影响:(（编辑：2016年2月24日上午9:17的bar28）



以下为原文

I went thru all internal 2.4mm-SMA semiridig cables, cleaned them carefully and connected back to correct torque.
Unfortunately no effect on spikes on trace :((

Edited by: bar28 on Feb 24, 2016 9:17 AM

你知道，这可能是由于一个叫做采样器弹跳的奇怪问题。
尝试在一个或两个端口添加3或6 dB衰减器，看看它是否消失。
另外，以最差情况下的尖峰为中心，以1 GHz，1601点为中心，以及显示航空公司和衰减器的相同结果。
它将有助于看到更高分辨率的尖峰。



以下为原文

You know, it might be due to an odd problem called sampler bounce. Try adding a 3 or 6 dB pad at one or both ports, and see if it goes away. Also, how about a new cal centered on the worst case spike, span about 1 GHz, 1601 points, and show the same results for airline and attenuator. It will help to see the spike in better resolution.

我曾想过在测试端口上添加3dB或6dB附加衰减器。
什么是安装这些衰减器的实用最佳方法 - 在VNA tesport里面有2.4mm semiridig电缆？编辑：bar28于2016年2月25日上午10:47



以下为原文

I have thought about adding 3dB or 6dB additional attenuator on the test ports. What is practicaly best way to install those attenuators -inside the VNA tesport where goes 2.4mm semiridig cable?

Edited by: bar28 on Feb 25, 2016 10:47 AM

现在，8722ES在服务公司中使用校准数据进行了校准，并且符合规格要求。
不幸的是，在同一个地方仍然存在小的尖峰。
当我用10Hz IFBW增加平均值达到10时，13.6GHz的最大尖峰从0.06降低到0.03dB。
步进扫描模式也被激活。
如果有人有新的想法如何最大限度地减少这些尖峰，请告诉我。
我忘了告诉，该分析仪配备了选件010,1DS和400.分析仪内部有步进衰减器。
它会引起这样的问题吗？



以下为原文

8722ES is now calibrated in service company with calibration data and went inside specs. Unfortunately small spikes on thru still exists on same places. When I have increased averaging up to 10 with 10Hz IFBW biggest spike on 13.6GHz has decreased from 0.06 to 0.03dB level. Step sweep mode is activated too. If someone has new ideas how to minimize those spikes on thru, please let me know. I forgot to tell, that analyzer is equipped with options 010, 1DS and 400. Analyzer has step attenuator inside. Can it cause such a problems?

8720中存在一种称为“采样器反弹”的奇怪现象，可能会导致信号出现微小尖峰。
如果为每个端口添加3-6 dB焊盘，然后在焊盘后校准并重新测量，请查看此问题是否消失。
（如果这有效，而你感兴趣的话，我可以进一步解释一下。我只想说我们不再使用采样器了）
此外，这是从记忆中导致8722被淘汰的东西就像12年前一样，有一个有趣的小刺，13.65 GHz（这实际上是一个带断点）引起了一点尖峰。
尝试将IF BW降低到10 Hz（这是指定仪器的方式），我认为尖峰会降低。
是的，我知道它很慢。
是的，我知道你宁愿没有穗。
但这是该技术在互联网发明之前所能做的最好的事情。



以下为原文

There is a strange phenomena in the 8720 called "sampler bounce" which can cause tiny spikes in the signals. If you add a 3-6 dB pad to each port, and then calibrate after the pads and re-measure, see if this issue disappears. (if this works, and you're interested, I can explain it a bit further. Suffice it to say we don't use samplers any more)..

Also, and this is from memory cause the 8722 was obsoleted something like 12 years ago, there was a funny little spur at 13.65 GHz (that's actually a band break point) that caused a little spike. Try reducing the IF BW to 10 Hz (which is how the instrument is specified) and I think the spike will reduce. Yes, I know it is very slow. Yes, I know you would rather not have the spike. But that was the best that the technology could do before the invention of the internet.

我们的实验室有另一个8720C VNA（50MHz-20GHz），我完成了从13GHz到14GHz的传输测试。
通过校准，IF100Hz，201点测试端口电缆的简单响应。
校准后，我测量了典型的7mm-7mm适配器。
在13,6GHz点出现完全相同的尖峰。
减少IF对该峰值的影响不大，但平均值更好。
我设法将该峰值降至0.02-0.03dB水平。
Joel博士是完全正确的，它是由乐队断点造成的。
听到其他用户注意到使用8720系列分析仪也会很高兴



以下为原文

Our lab has another 8720C VNA (50MHz-20GHz) and I done it transmission test from 13GHz to 14GHz. Simple response thru cal, IF100Hz, 201points testport cables together. After calibration I measured typical 7mm-7mm adapter. Totally same spike appeared on 13,6GHz point. Decreasing IF not effected on that spike so much, but averaging was better choise. I managed to drop that spike to 0.02-0.03dB level. Dr Joel was totally right that it caused by band break point. Would be still nice to hear another users notes too whose using 8720 series analyzers as well