HP 8591A频谱分析仪有一个小的中心频率变化

嗨，我不认为你真的有问题，如果你没有任何错误信息，那么我认为你的分析仪正在按预期工作。
频谱分析仪不是高精度测量频率的最佳仪器（特别是频率跨度不超过200kHz）。
如果您已将频谱分析仪频率锁定到任何高稳定10MHz信号源或类似信号，则您在发布时未提及。
原来这种类型的频谱分析仪依赖于石英晶体，频率可能略有不同。
这取决于晶体的温度等。我没有8591的CLIP，但惠普常常使用100MHz晶体或晶体振荡器。
为了确保您的测量，您应该让仪器加热至少30分钟。
还有一个频率校准应该完成，你可以在CAL菜单中找到它。
（我假设您对此很熟悉，但想要确定一下。）与300MHz参考信号相比，显示器上读取的所有频率都将被测量。
如果您的参考信号不正确，那么您的测量也将是错误的。
仍然是这种类型的频谱分析仪最适合测量不是精确频率的电平。
如果您的分析仪具有10MHz参考输入并且您有稳定的信号源，作为GPS接收器或类似设备，您将获得更加一致的结果。
你提到频率计数器。
如果您没有将其锁定到稳定的参考，您可能无法确定哪种仪器显示正确的频率。
有些类型的惠普分析仪带有晶体烤箱，这些更好，但仍然存在差异。
“准确”测量频率可能很棘手......作为比较，我的HP8563E和HP5350B（计数器）都锁定在GPS上。
如果我测量参考，我当然会得到300.000000MHz。
来自我的其他分析仪（HP8594带有自由运行的烤箱控制振荡器）的参考，计数器是11Hz错误。
HP8563E在200Hz范围内，RBW = VBW = 3Hz，我得到相同的计数结果。
我不认为8591可以这么窄，然后你将无法高精度测量。
享受你的8591，它仍然是一个非常好的乐器！
问候Jens



     以下为原文

  Hi,
I don't think you really have a problem, if you don't have any error messages then I think your analyzer is working as it's supposed to. A spectrum analyzer is not the best instrument for measuring a frequency with high accuracy, (and especially not with a frequency span of 200kHz). You didn't mention in your posting if you have locked the spectrum analyzer frequency to any source of high stable 10MHz signal or similar. Original this type of spectrum analyzer depend on a quartz crystal and the frequency can differ slightly. This depends on the temperature of the crystal etc. I don't have any CLIP for the 8591 but often HP have used 100MHz crystals or crystal oscillators. To be sure about your measurement you should let the instrument to heat up at least 30 minutes. Also there is a frequency calibration that should be done, you'll find it in the CAL menu. (I assume that you are familiar about this but wanted to mention it to be sure.)
All frequencies read on the display will be measured in comparison to the 300MHz reference signal. If your reference signal is not right, then your measurements will also be wrong. Still a spectrum analyzer of this type is best for measuring levels not exact frequencies. If your analyzer has an input of 10MHz reference and you have a stable source, as a GPS receiver or similar, you will get more consistant results from day to day.
You mention a frequency counter. This instrument can have the same "problem" and you can't be sure what instrument show the right frequency if you haven't locked it to a stable reference. There are types of HP analyzers with crystal ovens and these are better, but there can still be differences. Measuring frequencies "exactly" can be tricky...
As a comparison my HP8563E and HP5350B (counter) are both locked to GPS. If I measure the reference I will of course get 300.000000MHz. The reference from my other analyzer, (a HP8594 with free running oven controled oscillator), the counter is 11Hz wrong. With the HP8563E in 200Hz span and RBW=VBW=3Hz I get the same counted result.
I don't think the 8591 can go this narrow and then you will not be able to measure with high accuracy.
Enjoy your 8591, it's still a very good instrument!
Regards
Jens

你好Jens和所有其他人，我不认为石英晶体稳定性有问题，很快我就尝试了高稳定性10 MHz 0 dBm源。
这个问题更像是一个非常小的跨度中的频率锁定问题。
频谱分析仪输入端的稳定CW信号会使频率上下跳动一点点。
我的R＆amp; S频谱分析仪非常稳定。
关心并感谢你的响应，Hifreak更新：HP 8591A上的校准信号不稳定，我在背面的连接器上尝试了高稳定性的10 MHz信号源。
编辑：Hifreak于2014年4月6日上午8:39



     以下为原文

  Hello Jens and all others,

I do not think that there is a problem with quartz crystal stability, soon i try an high stability 10 MHz 0 dBm source.

The problem is more like a frequency lock problem in very little spans.
The frequency jumps a little bit up and down with a stable CW signal on the input of the spectrum analyzer.
My R&S spectrum analyzer is perfectly stable.

Regards and thank you already for your response,

Hifreak

Update: cal signal on the HP 8591A is not stable , i tried an high stability 10 MHz source on the connector on the back.

Edited by: Hifreak on Apr 6, 2014 8:39 AM

你好Hifreak，如果我理解你，当你测量300MHz参考输出时，你的R＆amp; S分析仪会得到一个稳定的读数，（？）。
使用其他仪器 - 参考信号的电平是否合适？
如果它比前面板上规定的要低10-15dB或更高，那么PLL锁定可能无法正常工作。
好吧，我没有任何关于8591的CLIP但是看看;
http://www.ko4bb.com/manuals/index.php?dir=HP_Agilent/HP_8590_Spectrum_Analyzer/HP_8590_Clip。
有些文件被命名为8591 ...所以也许有相似之处，（？）。
如果您不熟悉高压，请不要尝试打开分析仪！
必须考虑几个预防措施！
如果您熟悉这种类型的设备，将上述CLIP中提到的部件数与分析仪中的电路板进行比较可能会有所回报。
问候Jens



     以下为原文

  Hello Hifreak,
if I understand you right you get a stable readout on your R&S analyzer when you measure the 300MHz reference output, (?).
With the other instrument - is the level of the reference signal right? If it's considerable lower, 10-15dB or more, than stated on the frontpanel then the PLL lock might not work properly.

Well, I haven't any CLIP for the 8591 but have a look at; http://www.ko4bb.com/manuals/index.php?dir=HP_Agilent/HP_8590_Spectrum_Analyzer/HP_8590_Clip . Some of the files are named 8591... so perhaps there are similarities, (?).

Please do not try to open the analyzer if you're not familiar with high voltages! There are several precautions that must be taken into consideration!

If you are familiar working with this type of equipment, it might pay off to compare the partnumbers mentioned in the CLIP above with the boards in your analyzer.

Regards
Jens

您好HP 8590系列专家，我对HP8591A频谱分析仪的进一步了解，A25计数器板上的采样器匹配直流电压（A25TP1和A26TP2）非常低。
调整采样器匹配（A25C107）无助于在测试点上获得正确的直流电压。
我可以帮助我吗？
此致，Hifreak



     以下为原文

  Hello HP 8590 series experts,

I'm a little further with the HP8591A spectrum analyzer, the sampler match dc voltage (A25TP1 and A26TP2) on the A25 counterlock board is very low.

Adjusting the sampler match (A25C107) has not helped to get the right DC voltage on the test points.

Can anyone help me on my way?

Regards,

Hifreak

嗨，因为我不熟悉8591A，我无法肯定回答，但是我在采样器上有一个低电压的8563E，这是一个被破坏的TFM-2-38混音器。
这可能是第一个也是唯一一个我已经改变的环形二极管混频器。
我没有打开它来检查，但用标准的TFM-2取代了8563E启动并运行。
检查是否有一个类似的回路供给带混合器的采样器。
如果你检查调音台的水平，你会发现它是否坏了。
请注意，我没有声称你的调音台坏了 - 但是请检查性能，也许你有同样的错误。
关注JensEdited：sm7ovk于2014年4月25日下午2:26



     以下为原文

  Hi,
Since I'm not familar with the 8591A I can not answer for sure, but I had a 8563E with a low voltage on the sampler and that was a TFM-2-38 mixer that was broken. This is probably the first and only ring diode mixer I've changed as broken. I didn't open it to check, but replaced with a standard TFM-2 got the 8563E up and running. Check if you have a similar loop feeding the sampler that got a mixer. If you check the levels to and from the mixer you'll find out if it's broken. 
Please note that I don't claim that your mixer is broken - but please check the performance and perhaps you have the same fault.
Regards
Jens

Edited by: sm7ovk on Apr 25, 2014 2:26 PM