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你好,我相信我使用的PNA-X可能有一些内部硬件问题,但我想在发送之前进行验证。
我正在使用带标准接收器的PNA-X测量下变频器的噪声系数。 (没有噪音接收器选项)。 以前,我能够在有问题的PNA-X上测试单位,而噪音数字没有问题。 然而,最近,它在噪声系数波形中表现出尖锐的行为。 (见附件)。 我将DUT移动到另一个PNA-X并且它没有尖峰问题。 我还交换了有问题的PNA-X上的测试电缆并重新测量了测量,但波形中仍然出现了这些尖峰。 奇怪的部分是增益波形和回波损耗波形看起来很好,根本没有尖锐的行为。 我的问题是这样的。 我的假设是内部硬件问题是否正确? 或者在将其送回修理之前我可以尝试一些东西吗? 在PNA-X内部可能发生什么导致这种行为? 谢谢,rok 以上来自于谷歌翻译 以下为原文 Hello, I believe the PNA-X I am using might have some internal hardware problems, but I wanted to verify here before I send it out for repair. I am measuring the noise figure of a downconverter using a PNA-X with standard receivers. (do not have the noise receiver option). Previously, I was able to test units on that PNA-X in question with no issues on the noise figure. However, recently, its been exhibiting spiky behavior in the noise figure waveform. (see attached). I moved the DUT to another PNA-X and it didn't have the spikes issue. I also swapped the test cables on the PNA-X in question and retried the measurement, but still have those spikes appearing in the waveform. The strange part is the gain waveforms and return loss waveforms look good and have no spiky behavior at all. My question is as such. Is my assumption that it is a internal hardware issue correct? Or is there something that I can try prior to sending it back for repair? And what could be happening internally inside the PNA-X to cause such behavior? Thanks, rok 附件 |
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几个问题:1-您的转换器是屏蔽的还是暴露的RF电路?
2-从尖峰到扫描以及从一次测量到另一次测量,尖峰是否以相同的频率和幅度出现? 在NFX通道中添加跟踪DUTRNPI和SYSTRNPI。 这些痕迹也表现出相同的刺激吗? 4-为了获得最佳结果,当使用标准PNA接收器获得噪声系数时,您的转换器的增益+噪声必须足够高,以克服接收器的噪声系数。 当您比较校正后的DUTRNPI与SYSTRNPI时,DUT相对噪声功率应至少比系统相对噪声功率高10-15 dB; 那是这样的吗? 5-是您的转换器输出滤波(即LO馈通和其他混频器图像被滤除)? 您可以尝试的实验:1-设置噪声系数通道的放大器版本以进行CW测量,并将频率设置为IF频率,从而为您提供NFX通道中的最大尖峰(就像您设置中的20 GHz附近的大尖峰一样) )。 确保使用与NFX通道中使用的相同的噪声带宽和平均值。 还可以手动将RF和LO输入设置到转换器,以便获得我们正在调整噪声系数通道的IF频率。 在NFX通道中的2-注意该频率下的DUTRNPI值。 它与您使用NFX通道测量的相同吗? 3-如果相同,则将输出端口切换到另一个端口(在NFA通道中,您可以更改输出端口,但在NFX通道中不允许)。 如果你切换端口并仍然获得与端口2相同的相对噪声功率,那么可能不是你的接收器坏了,但是如果你切换端口并且你的噪声功率低得多,那么可能会有 端口2中的B接收器有问题,我们可以设置其他实验来验证。 以上来自于谷歌翻译 以下为原文 a few questions: 1- is your converter shielded or does it have exposed RF circuitry? 2- do the spikes show up at the same frequency and magnitude from sweep to sweep and from one measurement try to another? 3- in your NFX channel add the traces DUTRNPI and SYSTRNPI. do these traces also exhibit the same spurs? 4- for best results when using the standard PNA receivers for noise figure, your converter's Gain+Noise has to be high enough to overcome the receiver's noise figure. when you compare the corrected DUTRNPI versus SYSTRNPI, the DUT relative noise power should be at least 10-15 dB higher than the system relative noise power; is that the case here? 5- is the output of your converter filtered (i.e LO feedthrough and other mixer images are filtered out)? an experiment you can try: 1- setup the amplifier version of the noise figure channel for a CW measurement and set the frequency to the IF frequency that gives you the biggest spike in your NFX channel (like that big spike near 20 GHz in your setup). make sure to use the same noise bandwidth and averaging that you are using in the NFX channel. also set the RF and LO inputs to your converter manually, so that you get the IF frequency we are tuning the noise figure channel to. 2- in the NFX channel note the DUTRNPI value at that frequency. is it the same as what you measure with the NFX channel? 3- if it is the same, switch the output port to a different port (in the NFA channel, you can change the output port, but that is not allowed in the NFX channel). if you switch the port and still get the same relative noise power as you did with port 2, then it is probably not your receiver that is bad, but if you switch the port and you get a much lower lower noise power then there may be something wrong with the B receiver in port 2 and we can setup other experiments to verify that. |
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Topcbpcba 发表于 2019-7-3 15:46 嗨,这里有一些问题的答案。 我现在没有DUT进行测试,因此我只能提供部分答案。 1)转换器被屏蔽2)否。尖峰看起来是随机的,并不总是出现在相同的频率上,也没有从测量到测量的相同幅度。 3)我召回了1个坏噪声系统状态文件并添加了额外的跟踪。 似乎DUTRNPI迹线表现出类似的尖峰。 SYSTRNPI是扁平化的,但可能是因为我需要在装置到位时触发它。 4)对于所讨论的DUT,我们的增益+ NF> 40。 当我可以让另一个DUT进行测试时,问题的下一部分正在等待。 5)是的,转换器的输出被过滤。 一旦我得到另一个单位,我将尝试实验。 但正如我之前提到的,我在另一台PNA-X机器上测试了相同的单元,并且在其噪声系数测量中没有任何这些尖峰。 使用的状态文件是相同的; 唯一不同的是校准,测试电缆的状况和LO源。 我还尝试了一个不同的LO源,它产生了一个更清晰的信号(见附件),但波形内仍然有尖峰。 rokEdited by:rok on 2013年3月12日下午7:12 以上来自于谷歌翻译 以下为原文 Hi, Here's some answers to your questions. I don't have a DUT to test with right now, so I can only provide partial answers. 1) Converter is shielded 2) No. The spikes seem random in nature and do not always occur in the same frequency nor have the same magnitude from measurement to measurement. 3) I recalled 1 of the bad noise figure state files and added the extra traces. It seems that the DUTRNPI trace is exhibiting similar spikes. The SYSTRNPI is flatline, but probably because I need to trigger it with the unit in place. 4) Our gain+NF is > 40 for the DUT in question. The next part of the question is pending when I can get another DUT to test. 5) Yes, the output of the converter is filtered. Once I get another unit, I will try the experiments. But as I mentioned before, I tested the same unit on another PNA-X machine right next to the one in question and it didn't have any of these spikes in its noise figure measurement. The state file used is the same; the only thing different would be the calibration, the condition of the test cables, and the LO source. I also tried a different LO source, which yielded a cleaner signal (see attached), but still has spikes within the waveform. rok Edited by: rok on Mar 12, 2013 7:12 PM 附件 |
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Topcbpcba 发表于 2019-7-3 15:46 > {quote:title = daras写道:} {quote}> ....(在NFA频道中,您可以更改输出端口,但在NFX频道中不允许)。 我在这里说谎:-(如果噪音接收器设置为PNA接收器,你实际上可以改变NFX中的输出端口。我的盒子有低噪声接收器选项,我忘了在查看混音器设置选项卡之前更改接收器选择 。对于低噪声接收器,您只能使用端口2进行输出,但不能使用普通接收器。无论如何,您可以设置与现有相同的NFX测量,只需将输出端口更改为端口4( 我假设您正在使用其他一条关于更改LO的注释的外部LO)如果使用相同的DUT和电缆在两个不同的接收器中获得不同的DUTRNPI值,那么问题可能在接收器端, 但是如果你在两种情况下得到相同的杂散,那么问题可能在于来源。要验证这一点,断开DUT并在连接到PNA输出端口的电缆末端放置一个好的负载,看看是否有尖峰 走开DUTRNPI追踪。如果他们这样做,那么我们就知道了 接收器和电缆都很好。 如果没有,请拔下电缆并将负载直接连接到PNA上的testport连接器,然后重复相同的测量。 如果尖峰在此时消失,则问题出在电缆或连接器中。 以上来自于谷歌翻译 以下为原文 > {quote:title=daras wrote:}{quote} > ....(in the NFA channel, you can change the output port, but that is not allowed in the NFX channel). I told a lie here :-( you can actually change output ports in NFX if the noise receiver is set to the PNA receiver. My box has the low noise receiver option and I forgot to change the receiver selection before looking at the mixer setup tab. With the low noise receiver, you are restricted to port 2 for output, but not so in with the normal receiver. In any case, you can setup the same NFX measurement as you already have and simply change the output port to port 4 (I am assuming you are using an external LO from one of the other comments you made about changing LOs) if with the same DUT and cables you get a different value for DUTRNPI in two different receivers, then the issue is probably in the receiver side, but if you get the same spurs in both cases, then the problem might be with the source. to verify that, disconnect the DUT and put a good load on the end of the cable connected to output port of the PNA and see if the spikes go away on the DUTRNPI trace. If they do, then we know the receiver and the cable are fine. If they don't, remove the cable and connect the load directly to the testport connector on the PNA and repeat the same measurement. if the spikes go away at this point, then the problem is in the cable or the connectors. |
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Topcbpcba 发表于 2019-7-3 16:16 sysrnpi会告诉我们更多,但如果你看到它的尖峰,那么可能是由于内部LO有杂散信号。 通常情况下,这不会出现在VNA测量中(它们与正在进行的测量不同),但它可能对转换器NF测量产生影响。 对于转换器,您使用VNA提供LO吗? 如果是这样,请尝试LO的外部源(锁定为10 MHz)。 PNA多大了? 大约两年前有一个主要的合成器重新设计,其中一个改进是虚假的。 您可以直接联系jvall,因为这可能会转移到正式的支持问题,他就是那个人。 以上来自于谷歌翻译 以下为原文 The sysrnpi will tell us some more, but if you see the spike in it, then it might be due to the internal LO having spurious signals. Normally, this would not show up in a VNA measurement (they being off frequency from the measurement being made) but it could have an effect on a converter NF measurement. For the converter, are you using the VNA to provide the LO? If so, try an external source (locked to 10 MHz) fo the LO. How old is the PNA? There was a major synthesiszer re-design about 2 years ago, one of the things that improved was spurious. You might contact jvall directly as this is likely to move to a formal support issue, and he's the guy. |
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脑洞大赛9 发表于 2019-7-3 16:32 嗨,我公司的PNA-X(即型号N5244A)是在2010年采购的,所以它可能超过2年。 我实际上正在使用外部PSG通过PNA-X路由到下变频器的LO。 我已经与jvall就其他PNA-X固件错误(即缩放导致比例变化,s2p保存导致跟踪波形改变)进行了联系,因此我可以将其添加到列表中。 附上你想要的实验。 正如之前提到的那样,当我将输出端口切换到端口3时,尖峰消失了。 因此,端口2中的接收器很可能存在一些问题。如果还有其他实验需要执行,请告诉我。 否则,我会把它送去修理。 谢谢,rok 03_13_2013-cw nfcs uncalibrated.pdf20.9 KB03_13_2013-cw nfcs uncalibrated.pdf20.9 KB03_13_2013-nf uncalibrated.pdf46.3 KB03_13_2013-nf with extra traces.pdf49.7 KB 以上来自于谷歌翻译 以下为原文 Hi, My company's PNA-X's (i.e. model N5244A) were procured in 2010, so it could be greater than 2 years old. I am actually using an external PSG routed thru the PNA-X for the LO for the downconverter. I am already in contact with jvall regarding other PNA-X firmware bugs (i.e. zooming causing scale change, s2p saving causing trace waveform to change), so I might add this to the list. Attached are the experiments you wanted. As daras mentioned before, when I switch the output port to Port 3, the spikes disappeared. So most likely there is some issue with the receiver in port 2. If there's some other experiment to perform, let me know. Otherwise, I'll sent it out for repair. Thanks, rok 附件
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蓝色冰汐 发表于 2019-7-3 16:42 嗨,我上个月刚购买的PNA-X遇到了类似的问题。 我想知道你要做些什么来解决这个问题。 谢谢! -担 以上来自于谷歌翻译 以下为原文 Hi, I'm having a similar problem with a PNA-X that I just purchased last month. I wanted to know what you had to do to fix the problem. Thanks! -Dan |
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类似的问题是否意味着您在端口3上获得了良好的测量结果,但在端口2上却不是很好? 您可以发布问题图,并包括S21,NF,DUTRNPI,SYSRNPI曲线。 请结合尺度,使它们都一样。 噪声系数峰值的一个非常常见的问题是来自wifi和手机进入DUT的干扰信号。 以上来自于谷歌翻译 以下为原文 Does similar issue mean that you get good measuremetns on port 3, but not good on port 2? Can you post a plot of the issue, and include S21, NF, DUTRNPI, SYSRNPI traces. Please couple the scales so they are all the same. A very common problem with spikes in noise figure is interfering signals from wifi and cell phones getting into the DUT. |
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嗨丹,我公司不得不把PNA-X送去修理,以便修好。 自从您最近购买它以来,您应该能够获得保修服务。 但正如Joel博士建议的那样,最好有证据证明这个问题,基于要求的情节。 如果你在使用同一组电缆的测试持续时间大致相同的时间内在端口2而不是端口3上得到随机尖峰问题,则很可能是PNA-X接收器端有问题,而不是一些外部干扰。 一种简单的方法是使用Noise Figure测量创建2个窗口,其中1个窗口以端口2为参考,另一个窗口以端口3为参考。首先运行端口2的NF测量。 如果观察到尖峰,请保存波形。 接下来,将电缆切换到端口3,然后在另一个窗口中重复NF测试。 注意尖峰是否消失。 如果没有尖峰,则再次将其切换回端口2并重复进行NF测试。 如果它在端口2上可重复,您仍然应该看到随机尖峰。希望有帮助,rok 以上来自于谷歌翻译 以下为原文 Hi Dan, My company had to send the PNA-X out for repair in order to get it fixed. Since you recently bought it, you should be able to get warranty service for it. But it's best to have evidence of the problem, as Dr Joel is suggesting, based on the plots being asked for. If you get the random spike problem on Port 2 and not on Port 3 within roughly the same time testing duration using the same set of cables, then most likely it is the PNA-X receiver end with the issue, rather than some external interference. A simple way to do this would be to create 2 windows with the Noise Figure measurement, with 1 window referenced to port 2 and the other referenced to port 3. Run the NF measurement for port 2 first. If you observe the spike, save the waveform. Next, switch the cable to Port 3 and repeat the NF test in the other window. Note whether the spike disappears or not. If there are no spikes, then switch it back to Port 2 again and repeat the NF test. You should still see random spikes if it is repeatable on Port 2. Hope that helps, rok |
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